Cisco Systems Nexus 5596t User Manual

Cisco Nexus 5000 Series NX-OS Interfaces Configuration Guide, Release 5.2(1)N1(1)

First Published: July 02, 2012

Last Modified: July 02, 2012

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Text Part Number: 78-26881-OL

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Preface

CHAPTER 1

CHAPTER 2

Preface ix

Audience ix

Document Conventions ix

Documentation Feedback x

Obtaining Documentation and Submitting a Service Request xi

New and Changed Information for this Release 1

Configuring Layer 2 Interfaces 3

Information About Ethernet Interfaces 3

About the Interface Command 3

Information About Unified Ports 4

Guidelines and Limitations for Unified Ports 4

About the Unidirectional Link Detection Parameter 5

Default UDLD Configuration 5

UDLD Aggressive and Nonaggressive Modes 6

Interface Speed 6

About the Cisco Discovery Protocol 6

Default CDP Configuration 7

About the Error-Disabled State 7

About Port Profiles 8

Guidelines and Limitations for Port Profiles 9

About the Debounce Timer Parameters 9

About MTU Configuration 9

Configuring Ethernet Interfaces 10

Configuring a Layer 3 Interface on a Cisco Nexus 5500 Platform Switch 10

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Contents

Configuring Unified Ports 10

Configuring the UDLD Mode 12

Configuring Interface Speed 13

Disabling Link Negotiation 14

Configuring the CDP Characteristics 14

Enabling or Disabling CDP 15

Enabling the Error-Disabled Detection 16

Enabling the Error-Disabled Recovery 17

Configuring the Error-Disabled Recovery Interval 18

Port Profiles 19

Creating a Port Profile 19

Modifying a Port Profile 20

Enabling a Specific Port Profile 21

CHAPTER 3

Inheriting a Port Profile 22

Removing an Inherited Port Profile 23

Assigning a Port Profile to a Range of Interfaces 24

Removing a Port Profile from a Range of Interfaces 25

Configuration Examples for Port Profiles 26

Configuring the Debounce Timer 27

Configuring the Description Parameter 28

Disabling and Restarting Ethernet Interfaces 28

Displaying Interface Information 29

Default Physical Ethernet Settings 31

Configuring Layer 3 Interfaces 33

Information About Layer 3 Interfaces 33

Routed Interfaces 33

Subinterfaces 34

VLAN Interfaces 35

Loopback Interfaces 35

Tunnel Interfaces 36

Licensing Requirements for Layer 3 Interfaces 36

Guidelines and Limitations for Layer 3 Interfaces 36

Default Settings for Layer 3 Interfaces 36

Configuring Layer 3 Interfaces 36

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Contents

Configuring a Routed Interface 36

Configuring a Subinterface 37

Configuring the Bandwidth on an Interface 38

Configuring a VLAN Interface 39

Configuring a Loopback Interface 40

Assigning an Interface to a VRF 40

Verifying the Layer 3 Interfaces Configuration 41

Monitoring Layer 3 Interfaces 42

Configuration Examples for Layer 3 Interfaces 43

Related Documents for Layer 3 Interfaces 44

MIBs for Layer 3 Interfaces 44

Standards for Layer 3 Interfaces 44

CHAPTER 4

Configuring Port Channels 45

Information About Port Channels 45

Understanding Port Channels 45

Guidelines and Limitations for Port Channel Configuration 46

Compatibility Requirements 47

Load Balancing Using Port Channels 48

Understanding LACP 51

LACP Overview 51

LACP ID Parameters 52

Channel Modes 52

LACP Marker Responders 53

LACP-Enabled and Static Port Channel Differences 54

Configuring Port Channels 54

Creating a Port Channel 54

Adding a Port to a Port Channel 55

Configuring Load Balancing Using Port Channels 55

Configuring Hardware Hashing for Multicast Traffic 57

Enabling LACP 57

Configuring the Channel Mode for a Port 58

Configuring the LACP Fast Timer Rate 59

Configuring the LACP System Priority and System ID 60

Configuring the LACP Port Priority 60

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Contents

Disabling LACP Graceful Convergence 61

Reenabling LACP Graceful Convergence 62

Verifying Port Channel Configuration 63

Verifying the Load-Balancing Outgoing Port ID 64

CHAPTER 5

Configuring Virtual Port Channels 65

Information About vPCs 65

vPC Overview 65

Terminology 67

vPC Terminology 67

Fabric Extender Terminology 67

Supported vPC Topologies 68

Cisco Nexus 5000 Series Switch vPC Topology 68

Single Homed Fabric Extender vPC Topology 69

Dual Homed Fabric Extender vPC Topology 70

vPC Domain 70

Peer-Keepalive Link and Messages 71

Compatibility Parameters for vPC Peer Links 71

Configuration Parameters That Must Be Identical 71

Configuration Parameters That Should Be Identical 73

Graceful Type-1 Check 73

Per-VLAN Consistency Check 74

vPC Auto-Recovery 74

vPC Peer Links 74

vPC Peer Link Overview 74

vPC Number 75

vPC Interactions with Other Features 76

Configuring vPC Peer Links and Links to the Core 76

vPC and LACP 77

vPC Peer Links and STP 77

vPC and ARP 78

CFSoE 78

vPC Peer Switch 79

Guidelines and Limitations for vPCs 79

Configuring vPCs 80

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Contents

Enabling vPCs 80

Disabling vPCs 80

Creating a vPC Domain 81

Configuring a vPC Keepalive Link and Messages 82

Creating a vPC Peer Link 84

Checking the Configuration Compatibility 85

Enabling vPC Auto-Recovery 86

Suspending Orphan Ports on a Secondary Switch in a vPC Topology 87

Creating an EtherChannel Host Interface 88

Moving Other Port Channels into a vPC 89

Manually Configuring a vPC Domain MAC Address 90

Manually Configuring the System Priority 91

Manually Configuring a vPC Peer Switch Role 92

Configuring the vPC Peer Switch 93

Configuring a Pure vPC Peer Switch Topology 93

Configuring a Hybrid vPC Peer Switch Topology 94

Verifying the vPC Configuration 95

Viewing The Graceful Type-1 Check Status 96

Viewing A Global Type-1 Inconsistency 97

Viewing An Interface-Specific Type-1 Inconsistency 98

Viewing a Per-VLAN Consistency Status 99

vPC Example Configurations 101

Dual Homed Fabric Extender vPC Configuration Example 101

Single Homed Fabric Extender vPC Configuration Example 103

vPC Default Settings 105

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Contents

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Preface

This preface contains the following sections:

• Audience, page ix

• Document Conventions, page ix

• Documentation Feedback , page x

• Obtaining Documentation and Submitting a Service Request, page xi

Audience

This publication is for experienced network administrators who configure and maintain Cisco Nexus devices and Cisco Nexus 2000 Series Fabric Extenders.

Document Conventions

Command descriptions use the following conventions:

DescriptionConvention

bold

Italic

[x | y]

{x | y}

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Bold text indicates the commands and keywords that you enter literally as shown.

Italic text indicates arguments for which the user supplies the values.

Square brackets enclose an optional element(keyword or argument).[x]

Square brackets enclosing keywords or arguments separated by a vertical bar indicate an optional choice.

Braces enclosing keywords or arguments separated by a vertical bar indicate a required choice.

Documentation Feedback

Preface

DescriptionConvention

[x {y | z}]

Nested set of square brackets or braces indicate optional or required choices within optional or required elements. Braces and a vertical bar within square brackets indicate a required choice within an optional element.

variable

Indicates a variable for which you supply values, in context where italics cannot be used.

string

A nonquoted set of characters. Do not use quotation marks around the string or the string will include the quotation marks.

Examples use the following conventions:

DescriptionConvention

Terminal sessions and information the switch displays are in screen font.screen font

Information you must enter is in boldface screen font.boldface screen font

italic screen font

Arguments for which you supply values are in italic screen font.

Nonprinting characters, such as passwords, are in angle brackets.< >

Default responses to system prompts are in square brackets.[ ]

!, #

This document uses the following conventions:

Note

Means reader take note. Notes contain helpful suggestions or references to material not covered in the manual.

Caution

Means reader be careful. In this situation, you might do something that could result in equipment damage or loss of data.

Documentation Feedback

To provide technical feedback on this document, or to report an error or omission, please send your comments to nexus5k-docfeedback@cisco.com . We appreciate your feedback.

An exclamation point (!) or a pound sign (#) at the beginning of a line of code indicates a comment line.

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Preface

Obtaining Documentation and Submitting a Service Request

For information on obtaining documentation, submitting a service request, and gathering additional information, see the monthly What's New in Cisco Product Documentation, which also lists all new and revised Cisco technical documentation, at:

http://www.cisco.com/en/US/docs/general/whatsnew/whatsnew.html

Subscribe to the What's New in Cisco Product Documentation as a Really Simple Syndication (RSS) feed and set content to be delivered directly to your desktop using a reader application. The RSS feeds are a free service and Cisco currently supports RSS version 2.0.

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Obtaining Documentation and Submitting a Service Request

Preface

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CHAPTER 1

New and Changed Information for this Release

The following table provides an overview of the significant changes to this guide for this current release. The table does not provide an exhaustive list of all changes made to the configuration guides or of the new features in this release.

• New and Changed Information for this Release, page 1

New and Changed Information for this Release

Table 1: New Features

Where DocumentedDescriptionFeature

Added support for IPv6 addressing.IPv6

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• Routed Interfaces, on page

• Configuring a Subinterface,

on page 37

• Configuring the Bandwidth

on an Interface, on page 38

• Configuring a VLAN

Interface, on page 39

• Configuring a Loopback

Interface, on page 40

• Assigning an Interface to a

VRF, on page 40

New and Changed Information for this Release

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CHAPTER 2

Configuring Layer 2 Interfaces

This chapter contains the following sections:

• Information About Ethernet Interfaces, page 3

• Configuring Ethernet Interfaces, page 10

• Displaying Interface Information, page 29

• Default Physical Ethernet Settings , page 31

Information About Ethernet Interfaces

The Ethernet ports can operate as standard Ethernet interfaces connected to servers or to a LAN.

The Ethernet interfaces also support Fibre Channel over Ethernet (FCoE). FCoE allows the physical Ethernet link to carry both Ethernet and Fibre Channel traffic.

The Ethernet interfaces are enabled by default.

About the Interface Command

You can enable the various capabilities of the Ethernet interfaces on a per-interface basis using the interface command. When you enter the interface command, you specify the following information:

• Interface type—All physical Ethernet interfaces use the ethernet keyword.

• Slot number

◦ Slot 1 includes all the fixed ports.

◦ Slot 2 includes the ports on the upper expansion module (if populated).

◦ Slot 3 includes the ports on the lower expansion module (if populated).

◦ Slot 4 includes the ports on the lower expansion module (if populated).

• Port number— Port number within the group.

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Information About Unified Ports

The interface numbering convention is extended to support use with a Cisco Nexus 2000 Series Fabric Extender as follows:

switch(config)# interface ethernet [chassis/]slot/port

• Chassis ID is an optional entry to address the ports of a connected Fabric Extender. The chassis ID is configured on a physical Ethernet or EtherChannel interface on the switch to identify the Fabric Extender discovered via the interface. The chassis ID ranges from 100 to 199.

Information About Unified Ports

Cisco Nexus unified ports allow you to configure a physical port on a Cisco Nexus 5500 Platform switch as a 1/10-Gigabit Ethernet, Fibre Channel over Ethernet (FCoE), or 1-, 2-, 4-, 8-Gigabit native Fibre Channel port.

Currently, most networks have two types of switches for different types of networks. For example, LAN switches carry Ethernet traffic up to Catalyst switches and SAN switches carry FC traffic from servers to MDS switches. With unified port technology, you can deploy a unified platform, unified device, and unified wire approach. Unified ports allow you to move from an existing segregated platform approach where you choose LAN and SAN port options to transition to a single, unified fabric that is transparent and consistent with existing practices and management software. A unified fabric includes the following:

Configuring Layer 2 Interfaces

• Unified platform—Uses the same hardware platform and the same software code level and certifies it once for your LAN and SAN environments.

• Unified device—Runs LAN and SAN services on the same platform switch. The unified device allows you to connect your Ethernet and Fibre Channel cables to the same device.

• Unified wire—Converges LAN and SAN networks on a single converged network adapter (CNA) and connects them to your server.

A unified fabric allows you to manage Ethernet and FCoE features independently with existing Cisco tools.

Guidelines and Limitations for Unified Ports

• Ethernet ports and Fibre Channel ports must be configured in the following order:

• Fibre Channel ports must be configured from the last port of the module.

• Ethernet ports must be configured from the first port of the module.

If the order is not followed, the following errors are displayed:

ERROR: Ethernet range starts from first port of the module ERROR: FC range should end on last port of the module

• On the Cisco Nexus 5548UP switch, the 32 ports of the main slot (slot1) are unified ports. The Ethernet ports start from port 1/1 to port 1/32. The Fibre Channel ports start from port 1/32 backwards to port 1/1.

• For the Cisco Nexus 5596T switch, the last 16 ports (ports 33-48) are Fiber Channel and are configurable as unified ports. The first 32 ports (1-32) are 10GBase-T Ethernet ports only and cannot be configured as unified ports.

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Configuring Layer 2 Interfaces

About the Unidirectional Link Detection Parameter

The Cisco-proprietary Unidirectional Link Detection (UDLD) protocol allows ports that are connected through fiber optics or copper (for example, Category 5 cabling) Ethernet cables to monitor the physical configuration of the cables and detect when a unidirectional link exists. When the switch detects a unidirectional link, UDLD shuts down the affected LAN port and alerts the user. Unidirectional links can cause a variety of problems, including spanning tree topology loops.

UDLD is a Layer 2 protocol that works with the Layer 1 protocols to determine the physical status of a link. At Layer 1, autonegotiation takes care of physical signaling and fault detection. UDLD performs tasks that autonegotiation cannot perform, such as detecting the identities of neighbors and shutting down misconnected LAN ports. When you enable both autonegotiation and UDLD, Layer 1 and Layer 2 detections work together to prevent physical and logical unidirectional connections and the malfunctioning of other protocols.

A unidirectional link occurs whenever traffic transmitted by the local device over a link is received by the neighbor but traffic transmitted from the neighbor is not received by the local device. If one of the fiber strands in a pair is disconnected, as long as autonegotiation is active, the link does not stay up. In this case, the logical link is undetermined, and UDLD does not take any action. If both fibers are working normally at Layer 1, then UDLD at Layer 2 determines whether those fibers are connected correctly and whether traffic is flowing bidirectionally between the correct neighbors. This check cannot be performed by autonegotiation, because autonegotiation operates at Layer 1.

A Cisco Nexus device periodically transmits UDLD frames to neighbor devices on LAN ports with UDLD enabled. If the frames are echoed back within a specific time frame and they lack a specific acknowledgment (echo), the link is flagged as unidirectional and the LAN port is shut down. Devices on both ends of the link must support UDLD in order for the protocol to successfully identify and disable unidirectional links.

Note

By default, UDLD is locally disabled on copper LAN ports to avoid sending unnecessary control traffic on this type of media.

The following figure shows an example of a unidirectional link condition. Device B successfully receives traffic from Device A on the port. However, Device A does not receive traffic from Device B on the same port. UDLD detects the problem and disables the port.

Figure 1: Unidirectional Link

Default UDLD Configuration

The following table shows the default UDLD configuration.

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Interface Speed

Configuring Layer 2 Interfaces

Table 2: UDLD Default Configuration

Default ValueFeature

Globally disabledUDLD global enable state

DisabledUDLD aggressive mode

Enabled on all Ethernet fiber-optic LAN portsUDLD per-port enable state for fiber-optic media

UDLD per-port enable state for twisted-pair (copper) media

UDLD Aggressive and Nonaggressive Modes

UDLD aggressive mode is disabled by default. You can configure UDLD aggressive mode only on point-to-point links between network devices that support UDLD aggressive mode. If UDLD aggressive mode is enabled, when a port on a bidirectional link that has a UDLD neighbor relationship established stops receiving UDLD frames, UDLD tries to reestablish the connection with the neighbor. After eight failed retries, the port is disabled.

To prevent spanning tree loops, nonaggressive UDLD with the default interval of 15 seconds is fast enough to shut down a unidirectional link before a blocking port transitions to the forwarding state (with default spanning tree parameters).

When you enable the UDLD aggressive mode, the following occurs:

• One side of a link has a port stuck (both transmission and receive)

• One side of a link remains up while the other side of the link is down

In these cases, the UDLD aggressive mode disables one of the ports on the link, which prevents traffic from being discarded.

Disabled on all Ethernet 10/100 and 1000BASE-TX LAN ports

Interface Speed

The 5596T switch has 48 base board ports and 3 GEM slots. The first 32 ports are 10GBase-T ports the last 16 ports are SFP+ ports. The 10GBase-T ports support a speed of 1-Gigabit, 10-Gigabit, or Auto. The Auto setting automatically negotiates with the link parser to select either 1-Gigabit or 10-Gigabit speed.

About the Cisco Discovery Protocol

The Cisco Discovery Protocol (CDP) is a device discovery protocol that runs over Layer 2 (the data link layer) on all Cisco-manufactured devices (routers, bridges, access servers, and switches) and allows network management applications to discover Cisco devices that are neighbors of already known devices. With CDP, network management applications can learn the device type and the Simple Network Management Protocol (SNMP) agent address of neighboring devices running lower-layer, transparent protocols. This feature enables applications to send SNMP queries to neighboring devices.

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Configuring Layer 2 Interfaces

CDP runs on all media that support Subnetwork Access Protocol (SNAP). Because CDP runs over the data-link layer only, two systems that support different network-layer protocols can learn about each other.

Each CDP-configured device sends periodic messages to a multicast address, advertising at least one address at which it can receive SNMP messages. The advertisements also contain time-to-live, or holdtime information, which is the length of time a receiving device holds CDP information before discarding it. Each device also listens to the messages sent by other devices to learn about neighboring devices.

The switch supports both CDP Version 1 and Version 2.

Default CDP Configuration

The following table shows the default CDP configuration.

Table 3: Default CDP Configuration

About the Error-Disabled State

Default SettingFeature

EnabledCDP interface state

About the Error-Disabled State

An interface is in the error-disabled (err-disabled) state when the inteface is enabled administratively (using the no shutdown command) but disabled at runtime by any process. For example, if UDLD detects a unidirectional link, the interface is shut down at runtime. However, because the interface is administratively enabled, the interface status displays as err-disabled. Once an interface goes into the err-disabled state, you must manually reenable it or you can configure an automatic timeout recovery value. The err-disabled detection is enabled by default for all causes. The automatic recovery is not configured by default.

When an interface is in the err-disabled state, use the errdisable detect cause command to find information about the error.

You can configure the automatic err-disabled recovery timeout for a particular err-disabled cause by changing the time variable.

The errdisable recovery cause command provides automatic recovery after 300 seconds. To change the recovery period, use the errdisable recovery interval command to specify the timeout period. You can specify 30 to 65535 seconds.

If you do not enable the err-disabled recovery for the cause, the interface stays in the err-disabled state until you enter the shutdown and no shutdown commands. If the recovery is enabled for a cause, the interface is brought out of the err-disabled state and allowed to retry operation once all the causes have timed out. Use the show interface status err-disabled command to display the reason behind the error.

60 secondsCDP timer (packet update frequency)

180 secondsCDP holdtime (before discarding)

EnabledCDP Version-2 advertisements

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About Port Profiles

You can create a port profile that contains many interface commands and apply that port profile to a range of interfaces on the Cisco Nexus device. Port profiles can be applied to the following interface types:

• Ethernet

• VLAN network interface

• Port channel

A command that is included in a port profile can be configured outside of the port profile. If the new configuration in the port profile conflicts with the configurations that exist outside the port profile, the commands configured for an interface in configuration terminal mode have higher priority than the commands in the port profile. If changes are made to the interface configuration after a port profile is attached to it, and the configuration conflicts with that in the port profile, the configurations in the interface will be given priority.

You inherit the port profile when you attach the port profile to an interface or range of interfaces, When you attach, or inherit, a port profile to an interface or range of interfaces, the switch applies all the commands in that port profile to the interfaces.

You can have one port profile inherit the settings from another port profile. Inheriting another port profile allows the initial port profile to assume all of the commands of the second, inherited, port profile that do not conflict with the initial port profile. Four levels of inheritance are supported. The same port profile can be inherited by any number of port profiles.

To apply the port profile configurations to the interfaces, you must enable the specific port profile. You can configure and inherit a port profile onto a range of interfaces prior to enabling the port profile; you then enable that port profile for the configurations to take effect on the specified interfaces.

When you remove a port profile from a range of interfaces, the switch undoes the configuration from the interfaces first and then removes the port profile link itself. When you remove a port profile, the switch checks the interface configuration and either skips the port profile commands that have been overridden by directly entered interface commands or returns the command to the default value.

If you want to delete a port profile that has been inherited by other port profiles, you must remove the inheritance before you can delete the port profile.

You can choose a subset of interfaces from which to remove a port profile from among that group of interfaces that you originally applied the profile. For example, if you configured a port profile and configured ten interfaces to inherit that port profile, you can remove the port profile from just some of the specified ten interfaces. The port profile continues to operate on the remaining interfaces to which it is applied.

If you delete a specific configuration for a specified range of interfaces using the interface configuration mode, that configuration is also deleted from the port profile for that range of interfaces only. For example, if you have a channel group inside a port profile and you are in the interface configuration mode and you delete that port channel, the specified port channel is also deleted from the port profile as well.

After you inherit a port profile on an interface or range of interfaces and you delete a specific configuration value, that port profile configuration will not operate on the specified interfaces.

If you attempt to apply a port profile to the wrong type of interface, the switch returns an error.

When you attempt to enable, inherit, or modify a port profile, the switch creates a checkpoint. If the port profile configuration fails, the switch rolls back to the prior configuration and returns an error. A port profile is never only partially applied.

Configuring Layer 2 Interfaces

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Configuring Layer 2 Interfaces

Guidelines and Limitations for Port Profiles

Port profiles have the following configuration guidelines and limitations:

• Each port profile must have a unique name across interface types and the network.

• Commands that you enter under the interface mode take precedence over the port profile’s commands if there is a conflict. However, the port profile retains that command in the port profile.

• The port profile’s commands take precedence over the default commands on the interface, unless the default command explicitly overrides the port profile command.

• After you inherit a port profile onto an interface or range of interfaces, you can override individual configuration values by entering the new value at the interface configuration level. If you remove the individual configuration values at the interface configuration level, the interface uses the values in the port profile again.

• There are no default configurations associated with a port profile.

• A subset of commands are available under the port profile configuration mode, depending on which interface type that you specify.

About the Debounce Timer Parameters

• You cannot use port profiles with Session Manager.

About the Debounce Timer Parameters

The port debounce time is the amount of time that an interface waits to notify the supervisor of a link going down. During this time, the interface waits to see if the link comes back up. The wait period is a time when traffic is stopped.

You can enable the debounce timer for each interface and specify the delay time in milliseconds.

Caution

When you enable the port debounce timer the link up and link down detections are delayed, resulting in a loss of traffic during the debounce period. This situation might affect the convergence and reconvergence of some protocols.

About MTU Configuration

The Cisco Nexus device switch does not fragment frames. As a result, the switch cannot have two ports in the same Layer 2 domain with different maximum transmission units (MTUs). A per-physical Ethernet interface MTU is not supported. Instead, the MTU is set according to the QoS classes. You modify the MTU by setting class and policy maps.

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When you show the interface settings, a default MTU of 1500 is displayed for physical Ethernet interfaces and a receive data field size of 2112 is displayed for Fibre Channel interfaces.

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Configuring Layer 2 Interfaces

Configuring Ethernet Interfaces

The section includes the following topics:

Configuring a Layer 3 Interface on a Cisco Nexus 5500 Platform Switch

On Cisco Nexus devices, you can configure a Layer 3 interface.

You can change a Layer 3 interface into a Layer 2 interface by using the switchport command. You can change a Layer 2 interface into a Layer 3 interface by using the no switchport command.

Note

Procedure

Step 1

Step 2

Step 3

Step 4

This example shows how to configure a Layer 3 interface:

switch# configure terminal switch(config)# interface ethernet 1/2 switch(config-if)# no switchport switch(config-if)# no shutdown

Configuring Unified Ports

Before You Begin

Confirm that you have a supported Cisco Nexus switch. Unified Ports are available on the following Cisco Nexus switches:

switch(config)# interface ethernet slot/port

PurposeCommand or Action

Enters configuration mode.switch# configure terminal

Enters configuration mode for the specified interface.

Selects the Layer 3 interface.switch(config-if)# no switchport

Restarts the interface.switch(config-if)# no shutdown

• Cisco Nexus 5596T

• Cisco Nexus 5548UP

• Cisco Nexus 5596UP

• Cisco Nexus 5548P switch with an installed Cisco N55-M16UP expansion module

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Configuring Layer 2 Interfaces

If you're configuring a unified port as Fibre Channel or FCoE, confirm that you have enabled the feature fcoe command.

Procedure

Configuring Unified Ports

PurposeCommand or Action

Step 1

Step 2

Step 3

Step 4

Step 5

Step 6

switch(config) # slot slot number

switch(config-slot) # port port number type {ethernet | fc}

switch(config-slot) # copy

running-config startup-config

switch(config) # no port port number type fc

Enters global configuration mode.switch# configure terminal

Identifies the slot on the switch.

Configures a unified port as a native Fibre Channel port and an Ethernet port.

• type—Specifies the type of port to configure on a slot in a chassis.

• ethernet—Specifies an Ethernet port.

• fc—Specifies a Fibre Channel (FC) port.

Note

Changing unified ports on an expansion module (GEM) requires that you power cycle the GEM card. You do not have to reboot the entire switch for changes to take effect.

Copies the running configuration to the startup configuration.

Reboots the switch.switch(config-slot) # reload

Removes the unified port.

This example shows how to configure a unified port on a Cisco Nexus 5548UP switch or Cisco Nexus 5596UP switch:

switch# configure terminal switch(config)# slot 1 switch(config-slot)# port 32 type fc switch(config-slot)# copy running-config startup-config switch(config-slot)# reload

This example shows how to configure 20 ports as Ethernet ports and 12 as FC ports:

switch# configure terminal switch(config)# slot 1 switch(config-slot)# port 21-32 type fc switch(config-slot)# copy running-config startup-config switch(config-slot)# reload

This example shows how to configure a unified port on a Cisco N55-M16UP expansion module:

switch# configure terminal switch(config)# slot 2 switch(config-slot)# port 16 type fc switch(config-slot)# copy running-config startup-config switch(config-slot)# poweroff module 2 switch(config-slot)# no poweroff module 2

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Configuring the UDLD Mode

You can configure normal or aggressive unidirectional link detection (UDLD) modes for Ethernet interfaces on devices configured to run UDLD. Before you can enable a UDLD mode for an interface, you must make sure that UDLD is already enabled on the device that includes the interface. UDLD must also be enabled on the other linked interface and its device.

To use the normal UDLD mode, you must configure one of the ports for normal mode and configure the other port for the normal or aggressive mode. To use the aggressive UDLD mode, you must configure both ports for the aggressive mode.

Before you begin, UDLD must be enabled for the other linked port and its device.Note

Procedure

Configuring Layer 2 Interfaces

PurposeCommand or Action

Step 1

Step 2

Step 3

Step 4

Step 5

switch(config)# interface type slot/port

Enters configuration mode.switch# configure terminal

Enables UDLD for the device.switch(config)# feature udld

Disables UDLD for the device.switch(config)# no feature udld

Displays the UDLD status for the device.switch(config)# show udld global

Specifies an interface to configure, and enters interface configuration mode.

Step 6

Step 7

switch(config-if)# udld {enable | disable | aggressive}

switch(config-if)# show udld interface

Enables the normal UDLD mode, disables UDLD, or enables the aggressive UDLD mode.

Displays the UDLD status for the interface.

This example shows how to enable the UDLD for the switch:

switch# configure terminal switch(config)# feature udld

This example shows how to enable the normal UDLD mode for an Ethernet port:

switch# configure terminal switch(config)# interface ethernet 1/4 switch(config-if)# udld enable

This example shows how to enable the aggressive UDLD mode for an Ethernet port:

switch# configure terminal switch(config)# interface ethernet 1/4 switch(config-if)# udld aggressive

This example shows how to disable UDLD for an Ethernet port:

switch# configure terminal

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Configuring Layer 2 Interfaces

switch(config)# interface ethernet 1/4 switch(config-if)# udld disable

This example shows how to disable UDLD for the switch:

switch# configure terminal switch(config)# no feature udld

Configuring Interface Speed

The first 32 ports of a Cisco Nexus 5596T switch are switchable 1-Gigabit and 10-Gigabit ports. You can also configure them to auto-negotiate to either 1-Gigabit or 10-Gigabit. The last ports 33-48 are SFP+ ports and do not support auto negotiation.

Configuring Interface Speed

Note

If the interface and transceiver speed is mismatched, the SFP validation failed message is displayed when you enter the show interface ethernet slot/port command. For example, if you insert a 1-Gigabit SFP transceiver into a port without configuring the speed 1000 command, you will get this error. By default, all ports are 10 Gigabits.

Procedure

PurposeCommand or Action

Step 1

Step 2

switch(config)# interface type slot/port

Enters global configuration mode.switch# configure terminal

Enters interface configuration mode for the specified interface. This interface must have a 1-Gigabit Ethernet SFP transceiver inserted into it.

Step 3

speed

Sets the speed for a physical Ethernet interface.switch(config-if)# speed

For Cisco Nexus 5500 series switches, the speed argument can be set to one of the following:

• 1000—1 Gbps

• 10000—10Gbps

• auto

Note

100 Mbps is not a supported speed for the Cisco Nexus 5596 switch or CU-96 GEM card.

For the Cisco Nexus 5596T switch, the base board ports support 1 Gbps and 10 Gbps. On the 10GBase-T ports you can also choose auto.

The following example shows how to set the speed for a 1-Gigabit Ethernet port:

switch# configure terminal switch(config)# interface ethernet 1/4 switch(config-if)# speed 1000

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Disabling Link Negotiation

You can disable link negotiation using the no negotiate auto command. By default, auto-negotiation is enabled on 1-Gigabit ports and disabled on 10-Gigabit ports.

This command is equivalent to the Cisco IOS speed non-negotiate command.

Configuring Layer 2 Interfaces

Note

We do not recommend that you enable auto negotiation on 10-Gigabit ports. Enabling auto-negotiation on 10-Gigabit ports brings the link down. By default, link negotiation is disabled on 10-Gigabit ports.

Procedure

PurposeCommand or Action

Step 1

Step 2

Enters configuration mode.switch# configure terminal

Selects the interface and enters interface mode.switch(config)# interface ethernet

slot/port

Step 3

switch(config-if)# no negotiate auto

Disables link negotiation on the selected Ethernet interface (1-Gigabit port).

Step 4

switch(config-if)# negotiate auto

(Optional) Enables link negotiation on the selected Ethernet interface. The default for 1-Gigabit ports is enabled.

Note

This command is not applicable for 10GBase-T ports. It should not be used on 10GBase-T ports.

This example shows how to disable auto negotiation on a specified Ethernet interface (1-Gigabit port):

switch# configure terminal switch(config)# interface ethernet 1/1 switch(config-if)# no negotiate auto switch(config-if)#

This example shows how to enable auto negotiation on a specified Ethernet interface (1-Gigabit port):

switch# configure terminal switch(config)# interface ethernet 1/5 switch(config-if)# negotiate auto switch(config-if)#

Configuring the CDP Characteristics

You can configure the frequency of Cisco Discovery Protocol (CDP) updates, the amount of time to hold the information before discarding it, and whether or not to send Version-2 advertisements.

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Configuring Layer 2 Interfaces

Procedure

Enabling or Disabling CDP

PurposeCommand or Action

Step 1

Step 2

Step 3

Step 4

Step 5

switch(config)# [no] cdp advertise {v1 | v2 }

switch(config)# [no] cdp format device-id {mac-address | serial-number | system-name}

switch(config)# [no] cdp holdtime seconds

switch(config)# [no] cdp timer

seconds

Enters configuration mode.switch# configure terminal

(Optional) Configures the version to use to send CDP advertisements. Version-2 is the default state.

Use the no form of the command to return to its default setting.

(Optional) Configures the format of the CDP device ID. The default is the system name, which can be expressed as a fully qualified domain name.

Use the no form of the command to return to its default setting.

(Optional) Specifies the amount of time a receiving device should hold the information sent by your device before discarding it. The range is 10 to 255 seconds; the default is 180 seconds.

Use the no form of the command to return to its default setting.

(Optional) Sets the transmission frequency of CDP updates in seconds. The range is 5 to 254; the default is 60 seconds.

Use the no form of the command to return to its default setting.

This example shows how to configure CDP characteristics:

switch# configure terminal switch(config)# cdp timer 50 switch(config)# cdp holdtime 120 switch(config)# cdp advertise v2

Enabling or Disabling CDP

You can enable or disable CDP for Ethernet interfaces. This protocol works only when you have it enabled on both interfaces on the same link.

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Enabling the Error-Disabled Detection

Procedure

Configuring Layer 2 Interfaces

PurposeCommand or Action

Step 1

Step 2

switch(config)# interface type slot/port

Step 3

Step 4

This example shows how to enable CDP for an Ethernet port:

switch# configure terminal switch(config)# interface ethernet 1/4 switch(config-if)# cdp enable

This command can only be applied to a physical Ethernet interface.

Enabling the Error-Disabled Detection

You can enable error-disable (err-disabled) detection in an application. As a result, when a cause is detected on an interface, the interface is placed in an err-disabled state, which is an operational state that is similar to the link-down state.

Enters configuration mode.switch# configure terminal

Enters interface configuration mode for the specified interface.

Enables CDP for the interface.switch(config-if)# cdp enable

To work correctly, this parameter must be enabled for both interfaces on the same link.

Disables CDP for the interface.switch(config-if)# no cdp enable

Procedure

Step 1

Step 2

Step 3

Example:

switch# config t switch(config)#

errdisable detect cause {all | link-flap | loopback}

Example:

switch(config)# errdisable detect cause

all

switch(config)#

shutdown

Example:

switch(config)# shutdown switch(config)#

PurposeCommand or Action

Enters configuration mode.config t

Specifies a condition under which to place the interface in an err-disabled state. The default is enabled.

Brings the interface down administratively. To manually recover the interface from the err-disabled state, enter this command first.

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Configuring Layer 2 Interfaces

Enabling the Error-Disabled Recovery

PurposeCommand or Action

Step 4

no shutdown

Example:

switch(config)# no shutdown switch(config)#

Step 5

show interface status err-disabled

Example:

switch(config)# show interface status err-disabled

Step 6

copy running-config startup-config

Example:

switch(config)# copy running-config startup-config

This example shows how to enable the err-disabled detection in all cases:

switch(config)#errdisable detect cause all switch(config)#

Enabling the Error-Disabled Recovery

Brings the interface up administratively and enables the interface to recover manually from the err-disabled state.

Displays information about err-disabled interfaces.

(Optional) Copies the running configuration to the startup configuration.

You can specify the application to bring the interface out of the error-disabled (err-disabled) state and retry coming up. It retries after 300 seconds, unless you configure the recovery timer (see the errdisable recovery interval command).

Procedure

PurposeCommand or Action

Step 1

Enters configuration mode.config t

Example:

switch#config t switch(config)#

Step 2

errdisable recovery cause {all | udld | bpduguard | link-flap | failed-port-state | pause-rate-limit}

Specifies a condition under which the interface automatically recovers from the err-disabled state, and the device retries bringing the interface up. The device waits 300 seconds to

Example:

switch(config)#errdisable recovery cause

all

switch(config-if)#

retry. The default is disabled.

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Configuring the Error-Disabled Recovery Interval

Configuring Layer 2 Interfaces

PurposeCommand or Action

Step 3

show interface status err-disabled

Example:

switch(config)#show interface status err-disabled

Step 4

copy running-config startup-config

Example:

switch(config)#copy running-config startup-config

This example shows how to enable err-disabled recovery under all conditions:

switch(config)#errdisable recovery cause all switch(config)#

Configuring the Error-Disabled Recovery Interval

You can use this procedure to configure the err-disabled recovery timer value. The range is from 30 to 65535 seconds. The default is 300 seconds.

Procedure

Displays information about err-disabled interfaces.

(Optional) Copies the running configuration to the startup configuration.

Step 1

Step 2

Step 3

Step 4

Example:

switch#config t switch(config)#

errdisable recovery interval interval

Example:

switch(config)#errdisable recovery interval 32

switch(config-if)#

show interface status err-disabled

Example:

switch(config)#show interface status err-disabled

copy running-config startup-config

Example:

switch(config)#copy running-config startup-config

PurposeCommand or Action

Enters configuration mode.config t

Specifies the interval for the interface to recover from the err-disabled state. The range is from 30 to 65535 seconds. The default is 300 seconds.

Displays information about err-disabled interfaces.

(Optional) Copies the running configuration to the startup configuration.

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Configuring Layer 2 Interfaces

Port Profiles

Creating a Port Profile

Port Profiles

This example shows how to enable err-disabled recovery under all conditions:

switch(config)#errdisable recovery cause all switch(config)#

You can create a port profile on the switch. Each port profile must have a unique name across interface types and the network.

Procedure

PurposeCommand or Action

Step 1

Step 2

Step 3

Step 4

Step 5

Example:

switch# configure terminal switch(config)#

port-profile [type {ethernet | interface-vlan | port channel}] name

Example:

switch(config)# port-profile type ethernet

test

switch(config-port-prof)#

Example:

switch(config-port-prof)# exit switch(config)#

show port-profile

Example:

switch(config)# show port-profile name

copy running-config startup-config

Example:

switch(config)# copy running-config startup-config

Enters configuration mode.configure terminal

Creates and names a port profile for the specified type of interface and enters the port profile configuration mode.

Exits port profile configuration mode.exit

(Optional) Displays the port profile configuration.

(Optional) Copies the running configuration to the startup configuration.

This example shows how to create a port profile named test for Ethernet interfaces:

switch# configure terminal switch(config)# port-profile type ethernet test switch(config-port-prof)#

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Port Profiles

This example shows how to add the interface commands to a port profile named ppEth configured for Ethernet interfaces:

switch# configure terminal switch(config)# port-profile ppEth switch(config-port-prof)# switchport mode trunk switch(config-port-prof)# switchport trunk allowed vlan 300-400 switch(config-port-prof)# flowcontrol receive on switch(config-port-prof)# speed 10000 switch(config-port-prof)#

Modifying a Port Profile

You can modify a port profile in port-profile configuration mode.

You can remove commands from a port profile using the no form of the command. When you remove a command from the port profile, the corresponding command is removed from the interface that is attached to the port profile.

Procedure

Configuring Layer 2 Interfaces

Step 1

Step 2

Step 3

Step 4

Step 5

Example:

switch# configure terminal switch(config)#

port-profile [type {ethernet | interface-vlan | port channel}] name

Example:

switch(config)# port-profile type ethernet

test

switch(config-port-prof)#

Example:

switch(config-port-prof)# exit switch(config)#

show port-profile

Example:

switch(config)# show port-profile name

copy running-config startup-config

Example:

switch(config)# copy running-config startup-config

PurposeCommand or Action

Enters configuration mode.configure terminal

Enters the port profile configuration mode for the specified port profile and allows you to add or remove configurations to the profile.

Exits the port profile configuration mode.exit

(Optional) Displays the port profile configuration.

(Optional) Copies the running configuration to the startup configuration.

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Configuring Layer 2 Interfaces

This example shows how to remove commands from the port profile named ppEth configured for an Ethernet interface:

Enabling a Specific Port Profile

Procedure

Port Profiles

PurposeCommand or Action

Step 1

Step 2

Step 3

Step 4

Step 5

Step 6

Example:

switch# configure terminal switch(config)#

port-profile [type {ethernet | interface-vlan | port channel}] name

Example:

switch(config)# port-profile type ethernet test switch(config-port-prof)# no shutdown switch(config-port-prof)#

state enabled name

Example:

switch(config-port-prof)# state enabled switch(config-port-prof)#

exit

Example:

switch(config-port-prof)# exit switch(config)#

show port-profile

Example:

switch(config)# show port-profile name

copy running-config startup-config

Example:

switch(config)# copy running-config startup-config

Enters configuration mode.configure terminal

Enters the port profile configuration mode for the specified port profile.

Enables the port profile.

Exits the port profile configuration mode.

(Optional) Displays the port profile configuration.

(Optional) Copies the running configuration to the startup configuration.

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Port Profiles

This example shows how to enter port profile configuration mode and enable the port profile:

switch# configure terminal switch(config)# port-profile type ethernet test switch(config-port-prof)# state enabled switch(config-port-prof)#

Inheriting a Port Profile

You can inherit a port profile onto an existing port profile. The switch supports four levels of inheritance.

Procedure

Configuring Layer 2 Interfaces

PurposeCommand or Action

Step 1

Step 2

Step 3

Step 4

Step 5

Step 6

Example:

switch# configure terminal switch(config)#

port-profile name

Example:

switch(config)# port-profile test switch(config-port-prof)#

inherit port-profile name

Example:

switch(config-port-prof)# inherit port-profile adam switch(config-port-prof)#

Example:

switch(config-port-prof)# exit switch(config)#

show port-profile

Example:

switch(config)# show port-profile name

copy running-config startup-config

Example:

switch(config)# copy running-config startup-config

Enters configuration mode.configure terminal

Enters port profile configuration mode for the specified port profile.

Inherits another port profile onto the existing one. The original port profile assumes all the configurations of the inherited port profile.

Exits the port profile configuration mode.exit

(Optional) Displays the port profile configuration.

(Optional) Copies the running configuration to the startup configuration.

This example shows how to inherit the port profile named adam onto the port profile named test:

switch# configure terminal switch(config)# port-profile test switch(config-ppm)# inherit port-profile adam switch(config-ppm)#

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Configuring Layer 2 Interfaces

This example shows how to add the interface commands to a port profile named ppEth configured for Ethernet interfaces:

This example shows how to inherit a port profile named ppEth configured for Ethernet interfaces into an existing port profile named test:

switch# configure terminal switch(config)# port-profile test switch(config-port-prof)# inherit port-profile ppEth switch(config-port-prof)#

This example shows how to assign a port profile named ppEth configured for Ethernet interfaces to a range of Ethernet interfaces:

switch# configure terminal switch(config)# interface ethernet 1/2-5 switch(config-if)# inherit port-profile ppEth switch(config-if)#

This example shows how to remove an inherited port profile named ppEth from an existing port profile named test:

switch# configure terminal switch(config)# port-profile test switch(config-port-prof)# no inherit port-profile ppEth switch(config-port-prof)#

Port Profiles

Removing an Inherited Port Profile

You can remove an inherited port profile.

Procedure

Step 1

Example:

switch# configure terminal switch(config)#

Step 2

Step 3

port-profile name

Example:

switch(config)# port-profile test switch(config-port-prof)#

no inherit port-profile name

Example:

switch(config-port-prof)# no inherit port-profile adam switch(config-port-prof)#

PurposeCommand or Action

Enters configuration mode.configure terminal

Enters port profile configuration mode for the specified port profile.

Removes an inherited port profile from this port profile.

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Port Profiles

Configuring Layer 2 Interfaces

PurposeCommand or Action

Step 4

Example:

switch(config-port-prof)# exit switch(config)#

Step 5

show port-profile

Example:

switch(config)# show port-profile name

Step 6

copy running-config startup-config

Example:

switch(config)# copy running-config startup-config

This example shows how to remove the inherited port profile named adam from the port profile named test:

switch# configure terminal switch(config)# port-profile test switch(config-ppm)# no inherit port-profile adam switch(config-ppm)#

Assigning a Port Profile to a Range of Interfaces

Exits the port profile configuration mode.exit

(Optional) Displays the port profile configuration.

(Optional) Copies the running configuration to the startup configuration.

You can assign a port profile to an interface or to a range of interfaces. All of the interfaces must be the same type.

Procedure

PurposeCommand or Action

Step 1

Enters configuration mode.configure terminal

Example:

switch# configure terminal switch(config)#

Step 2

interface [ethernet slot/port | interface-vlan vlan-id

Selects the range of interfaces.

| port-channel number]

Example:

switch(config)# interface ethernet 7/3-5, 10/2, 11/20-25 switch(config-if)#

Step 3

inherit port-profile name

Assigns the specified port profile to the selected interfaces.

Example:

switch(config-if)# inherit port-profile adam switch(config-if)#

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Configuring Layer 2 Interfaces

Port Profiles

PurposeCommand or Action

Step 4

Example:

switch(config-port-prof)# exit switch(config)#

Step 5

show port-profile

Example:

switch(config)# show port-profile name

Step 6

copy running-config startup-config

Example:

switch(config)# copy running-config startup-config

This example shows how to assign the port profile named adam to Ethernet interfaces 2/3 to 2/5, 3/2, and 1/20 to 1/25:

switch# configure terminal switch(config)# interface ethernet 2/3 to 2/5, 3/2, and 1/20 to 1/25 switch(config-if)# inherit port-profile adam switch(config-if)#

Removing a Port Profile from a Range of Interfaces

Exits port profile configuration mode.exit

(Optional) Displays the port profile configuration.

(Optional) Copies the running configuration to the startup configuration.

You can remove a port profile from some or all of the interfaces to which you have applied the profile.

Procedure

PurposeCommand or Action

Step 1

Enters configuration mode.configure terminal

Example:

switch# configure terminal switch(config)#

Step 2

interface [ethernet slot/port | interface-vlan vlan-id

Selects the range of interfaces.

| port-channel number]

Example:

switch(config)# interface ethernet 7/3-5, 10/2, 11/20-25 switch(config-if)#

Step 3

no inherit port-profile name

Removes the specified port profile from the selected interfaces.

Example:

switch(config-if)# no inherit port-profile adam switch(config-if)#

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Port Profiles

Configuring Layer 2 Interfaces

PurposeCommand or Action

Step 4

Example:

switch(config-port-prof)# exit switch(config)#

Step 5

show port-profile

Example:

switch(config)# show port-profile name

Step 6

copy running-config startup-config

Example:

switch(config)# copy running-config startup-config

This example shows how tos remove the port profile named adam from Ethernet interfaces 1/3-5:

switch# configure terminal switch(config)# interface ethernet 1/3-5 switch(config-if)# no inherit port-profile adam switch(config-if)#

Configuration Examples for Port Profiles

Exits port profile configuration mode.exit

(Optional) Displays the port profile configuration.

(Optional) Copies the running configuration to the startup configuration.

The following example shows how to configure a port profile, inherit the port profile on an Ethernet interface, and enabling the port profile.

switch(config)# switch(config)# show running-config interface Ethernet1/14

!Command: show running-config interface Ethernet1/14 !Time: Thu Aug 26 07:01:32 2010

version 5.0(2)N1(1)

interface Ethernet1/14

switch(config)# port-profile type ethernet alpha switch(config-port-prof)# switchport mode trunk switch(config-port-prof)# switchport trunk allowed vlan 10-15 switch(config-port-prof)# switch(config-port-prof)# show running-config port-profile alpha

!Command: show running-config port-profile alpha !Time: Thu Aug 26 07:02:29 2010

version 5.0(2)N1(1) port-profile type ethernet alpha

switchport mode trunk switchport trunk allowed vlan 10-15

switch(config-port-prof)# int eth 1/14 switch(config-if)# inherit port-profile alpha switch(config-if)# switch(config-if)# port-profile type ethernet alpha switch(config-port-prof)# state enabled switch(config-port-prof)#

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Configuring Layer 2 Interfaces

switch(config-port-prof)# sh running-config interface ethernet 1/14

!Command: show running-config interface Ethernet1/14 !Time: Thu Aug 26 07:03:17 2010

version 5.0(2)N1(1)

interface Ethernet1/14

inherit port-profile alpha

switch(config-port-prof)# sh running-config interface ethernet 1/14 expand-port-profile

!Command: show running-config interface Ethernet1/14 expand-port-profile !Time: Thu Aug 26 07:03:21 2010

version 5.0(2)N1(1)

interface Ethernet1/14

switchport mode trunk switchport trunk allowed vlan 10-15

switch(config-port-prof)#

Configuring the Debounce Timer

You can enable the debounce timer for Ethernet ports by specifying a debounce time (in milliseconds) or disable the timer by specifying a debounce time of 0.

You can show the debounce times for all of the Ethernet ports by using the show interface debounce command.

To enable or disable the debounce timer, perform this task:

Procedure

PurposeCommand or Action

Step 1

Step 2

switch(config)# interface type slot/port

Enters configuration mode.switch# configure terminal

Enters interface configuration mode for the specified interface.

Step 3

switch(config-if)# link debounce time

milliseconds

Enables the debounce timer for the amount of time (1 to 5000 milliseconds) specified.

Disables the debounce timer if you specify 0 milliseconds.

This example shows how to enable the debounce timer and set the debounce time to 1000 milliseconds for an Ethernet interface:

switch# configure terminal switch(config)# interface ethernet 1/4 switch(config-if)# link debounce time 1000

This example shows how to disable the debounce timer for an Ethernet interface:

switch# configure terminal switch(config)# interface ethernet 1/4 switch(config-if)# link debounce time 0

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Configuring the Description Parameter

You can provide textual interface descriptions for the Ethernet ports.

Procedure

Configuring Layer 2 Interfaces

PurposeCommand or Action

Step 1

Step 2

Step 3

switch(config)# interface type slot/port

switch(config-if)# description test

This example shows how to set the interface description to Server 3 Interface:

switch# configure terminal switch(config)# interface ethernet 1/3 switch(config-if)# description Server 3 Interface

Disabling and Restarting Ethernet Interfaces

You can shut down and restart an Ethernet interface. This action disables all of the interface functions and marks the interface as being down on all monitoring displays. This information is communicated to other network servers through all dynamic routing protocols. When shut down, the interface is not included in any routing updates.

Procedure

Enters configuration mode.switch# configure terminal

Enters interface configuration mode for the specified interface.

Specifies the description for the interface.

PurposeCommand or Action

Step 1

Step 2

switch(config)# interface type slot/port

Enters configuration mode.switch# configure terminal

Enters interface configuration mode for the specified interface.

Step 3

Step 4

Disables the interface.switch(config-if)# shutdown

Restarts the interface.switch(config-if)# no shutdown

This example shows how to disable an Ethernet port:

switch# configure terminal switch(config)# interface ethernet 1/4 switch(config-if)# shutdown

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Configuring Layer 2 Interfaces

This example shows how to restart an Ethernet interface:

switch# configure terminal switch(config)# interface ethernet 1/4 switch(config-if)# no shutdown

Displaying Interface Information

To view configuration information about the defined interfaces, perform one of these tasks:

Displaying Interface Information

PurposeCommand

switch# show interface type slot/port

Displays the detailed configuration of the specified interface.

switch# show interface type slot/port capabilities

Displays detailed information about the capabilities of the specified interface. This option is only available for physical interfaces

switch# show interface type slot/port transceiver

Displays detailed information about the transceiver connected to the specified interface. This option is only available for physical interfaces.

Displays the status of all interfaces.switch# show interface brief

Displays the debounce status of all interfaces.switch# show interface debounce

switch# show interface flowcontrol

Displays the detailed listing of the flow control settings on all interfaces.

Displays information about the port profiles.show port--profile

The show interface command is invoked from EXEC mode and displays the interface configurations. Without any arguments, this command displays the information for all the configured interfaces in the switch.

This example shows how to display the physical Ethernet interface:

switch# show interface ethernet 1/1

Ethernet1/1 is up Hardware is 1000/10000 Ethernet, address is 000d.eca3.5f08 (bia 000d.eca3.5f08) MTU 1500 bytes, BW 10000000 Kbit, DLY 10 usec,

reliability 255/255, txload 190/255, rxload 192/255 Encapsulation ARPA Port mode is trunk full-duplex, 10 Gb/s, media type is 1/10g Input flow-control is off, output flow-control is off Auto-mdix is turned on Rate mode is dedicated Switchport monitor is off Last clearing of "show interface" counters never 5 minute input rate 942201806 bytes/sec, 14721892 packets/sec 5 minute output rate 935840313 bytes/sec, 14622492 packets/sec Rx

129141483840 input packets 0 unicast packets 129141483847 multicast packets 0 broadcast packets 0 jumbo packets 0 storm suppression packets 8265054965824 bytes 0 No buffer 0 runt 0 Overrun

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Displaying Interface Information

0 crc 0 Ignored 0 Bad etype drop 0 Bad proto drop

119038487241 output packets 119038487245 multicast packets

0 broadcast packets 0 jumbo packets

7618463256471 bytes 0 output CRC 0 ecc 0 underrun 0 if down drop 0 output error 0 collision 0 deferred 0 late collision 0 lost carrier 0 no carrier 0 babble 0 Rx pause 8031547972 Tx pause 0 reset

This example shows how to display the physical Ethernet capabilities:

switch# show interface ethernet 1/1 capabilities Ethernet1/1

Model: 734510033 Type: 10Gbase-(unknown) Speed: 1000,10000 Duplex: full Trunk encap. type: 802.1Q Channel: yes Broadcast suppression: percentage(0-100) Flowcontrol: rx-(off/on),tx-(off/on) Rate mode: none QOS scheduling: rx-(6q1t),tx-(1p6q0t) CoS rewrite: no ToS rewrite: no SPAN: yes UDLD: yes Link Debounce: yes Link Debounce Time: yes MDIX: no FEX Fabric: yes

This example shows how to display the physical Ethernet transceiver:

switch# show interface ethernet 1/1 transceiver Ethernet1/1

sfp is present name is CISCO-EXCELIGHT part number is SPP5101SR-C1 revision is A serial number is ECL120901AV nominal bitrate is 10300 MBits/sec Link length supported for 50/125mm fiber is 82 m(s) Link length supported for 62.5/125mm fiber is 26 m(s) cisco id is -cisco extended id number is 4

This example shows how to display a brief interface status (some of the output has been removed for brevity):

switch# show interface brief

Configuring Layer 2 Interfaces

-------------------------------------------------------------------------------Ethernet VLAN Type Mode Status Reason Speed Port Interface Ch #

-------------------------------------------------------------------------------Eth1/1 200 eth trunk up none 10G(D) -Eth1/2 1 eth trunk up none 10G(D) -Eth1/3 300 eth access down SFP not inserted 10G(D) -Eth1/4 300 eth access down SFP not inserted 10G(D) -Eth1/5 300 eth access down Link not connected 1000(D) -Eth1/6 20 eth access down Link not connected 10G(D) -Eth1/7 300 eth access down SFP not inserted 10G(D) -...

This example shows how to display the link debounce status (some of the output has been removed for brevity):

switch# show interface debounce

-------------------------------------------------------------------------------Port Debounce time Value(ms)

-------------------------------------------------------------------------------... Eth1/1 enable 100 Eth1/2 enable 100

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Configuring Layer 2 Interfaces

Eth1/3 enable 100 ...

This example shows how to display the CDP neighbors:

Default Physical Ethernet Settings

Note

The default device ID field for CDP advertisement is the hostname and serial number, as in the example above.

switch# show cdp neighbors Capability Codes: R - Router, T - Trans-Bridge, B - Source-Route-Bridge

Device ID Local Intrfce Hldtme Capability Platform Port ID d13-dist-1 mgmt0 148 S I WS-C2960-24TC Fas0/9 n5k(FLC12080012) Eth1/5 8 S I s N5K-C5020P-BA Eth1/5

S - Switch, H - Host, I - IGMP, r - Repeater, V - VoIP-Phone, D - Remotely-Managed-Device, s - Supports-STP-Dispute

Default Physical Ethernet Settings

The following table lists the default settings for all physical Ethernet interfaces:

Default SettingParameter

Enable, 100 millisecondsDebounce

Auto (full-duplex)Duplex

ARPAEncapsulation

1500 bytesMTU

AccessPort Mode

Auto (10000)Speed

MTU cannot be changed per-physical Ethernet interface. You modify MTU by selecting maps of QoS classes.

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Default Physical Ethernet Settings

Configuring Layer 2 Interfaces

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CHAPTER 3

Configuring Layer 3 Interfaces

This chapter contains the following sections:

• Information About Layer 3 Interfaces, page 33

• Licensing Requirements for Layer 3 Interfaces, page 36

• Guidelines and Limitations for Layer 3 Interfaces, page 36

• Default Settings for Layer 3 Interfaces, page 36

• Configuring Layer 3 Interfaces, page 36

• Verifying the Layer 3 Interfaces Configuration, page 41

• Monitoring Layer 3 Interfaces, page 42

• Configuration Examples for Layer 3 Interfaces, page 43

• Related Documents for Layer 3 Interfaces, page 44

• MIBs for Layer 3 Interfaces, page 44

• Standards for Layer 3 Interfaces, page 44

Information About Layer 3 Interfaces

Layer 3 interfaces forward packets to another device using static or dynamic routing protocols. You can use Layer 3 interfaces for IP routing and inter-VLAN routing of Layer 2 traffic.

Routed Interfaces

You can configure a port as a Layer 2 interface or a Layer 3 interface. A routed interface is a physical port that can route IP traffic to another device. A routed interface is a Layer 3 interface only and does not support Layer 2 protocols, such as the Spanning Tree Protocol (STP).

All Ethernet ports are switched interfaces by default. You can change this default behavior with the CLI setup script or through the system default switchport command.

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Subinterfaces

Configuring Layer 3 Interfaces

You can assign an IP address to the port, enable routing, and assign routing protocol characteristics to this routed interface.

You can assign a static MAC address to a Layer 3 interface. For information on configuring MAC addresses, see the Layer 2 Switching Configuration Guide for your device.

You can also create a Layer 3 port channel from routed interfaces.

Routed interfaces and subinterfaces support exponentially decayed rate counters. Cisco NX-OS tracks the following statistics with these averaging counters:

• Input packets/sec

• Output packets/sec

• Input bytes/sec

• Output bytes/sec

You can create virtual subinterfaces on a parent interface configured as a Layer 3 interface. A parent interface can be a physical port or a port channel.

Subinterfaces divide the parent interface into two or more virtual interfaces on which you can assign unique Layer 3 parameters such as IP addresses and dynamic routing protocols. The IP address for each subinterface should be in a different subnet from any other subinterface on the parent interface.

You create a subinterface with a name that consists of the parent interface name (for example, Ethernet 2/1) followed by a period and then by a number that is unique for that subinterface. For example, you could create a subinterface for Ethernet interface 2/1 named Ethernet 2/1.1 where .1 indicates the subinterface.

Cisco NX-OS enables subinterfaces when the parent interface is enabled. You can shut down a subinterface independent of shutting down the parent interface. If you shut down the parent interface, Cisco NX-OS shuts down all associated subinterfaces as well.

One use of subinterfaces is to provide unique Layer 3 interfaces to each VLAN that is supported by the parent interface. In this scenario, the parent interface connects to a Layer 2 trunking port on another device. You configure a subinterface and associate the subinterface to a VLAN ID using 802.1Q trunking.

The following figure shows a trunking port from a switch that connects to router B on interface E 2/1. This interface contains three subinterfaces that are associated with each of the three VLANs that are carried by the trunking port.

Figure 2: Subinterfaces for VLANs

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Configuring Layer 3 Interfaces

VLAN Interfaces

A VLAN interface or a switch virtual interface (SVI) is a virtual routed interface that connects a VLAN on the device to the Layer 3 router engine on the same device. Only one VLAN interface can be associated with a VLAN, but you need to configure a VLAN interface for a VLAN only when you want to route between VLANs or to provide IP host connectivity to the device through a virtual routing and forwarding (VRF) instance that is not the management VRF. When you enable VLAN interface creation, Cisco NX-OS creates a VLAN interface for the default VLAN (VLAN 1) to permit remote switch administration.

You must enable the VLAN network interface feature before you can configure it. The system automatically takes a checkpoint prior to disabling the feature, and you can roll back to this checkpoint. For information about rollbacks and checkpoints, see the System Management Configuration Guide for your device.

You cannot delete the VLAN interface for VLAN 1.Note

You can route across VLAN interfaces to provide Layer 3 inter-VLAN routing by configuring a VLAN interface for each VLAN that you want to route traffic to and assigning an IP address on the VLAN interface. For more information on IP addresses and IP routing, see the Unicast Routing Configuration Guide for your device.

The following figure shows two hosts connected to two VLANs on a device. You can configure VLAN interfaces for each VLAN that allows Host 1 to communicate with Host 2 using IP routing between the VLANs. VLAN 1 communicates at Layer 3 over VLAN interface 1and VLAN 10 communicates at Layer 3 over VLAN interface 10.

VLAN Interfaces

Figure 3: Connecting Two VLANs with VLAN Interfaces

Loopback Interfaces

A loopback interface is a virtual interface with a single endpoint that is always up. Any packet that is transmitted over a loopback interface is immediately received by this interface. Loopback interfaces emulate a physical interface.

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Tunnel Interfaces

You can use loopback interfaces for performance analysis, testing, and local communications. Loopback interfaces can act as a termination address for routing protocol sessions. This loopback configuration allows routing protocol sessions to stay up even if some of the outbound interfaces are down.

Tunnel Interfaces

Cisco NX-OS supports tunnel interfaces as IP tunnels. IP tunnels can encapsulate a same- ayer or higher layer protocol and transport the result over IP through a tunnel that is created between two routers.

Licensing Requirements for Layer 3 Interfaces

This feature does not require a license. Any feature not included in a license package is bundled with the Cisco NX-OS system images and is provided at no extra charge to you. For a complete explanation of the Cisco NX-OS licensing scheme, see the Cisco NX-OS Licensing Guide.

Configuring Layer 3 Interfaces

Guidelines and Limitations for Layer 3 Interfaces

Layer 3 interfaces have the following configuration guidelines and limitations:

• If you change a Layer 3 interface to a Layer 2 interface, Cisco NX-OS shuts down the interface, reenables the interface, and removes all configuration specific to Layer 3.

• If you change a Layer 2 interface to a Layer 3 interface, Cisco NX-OS shuts down the interface, reenables the interface, and deletes all configuration specific to Layer 2.

Default Settings for Layer 3 Interfaces

The default setting for the Layer 3 Admin state is Shut.

Configuring Layer 3 Interfaces

Configuring a Routed Interface

Procedure

PurposeCommand or Action

Step 1

Step 2

slot/port

Step 3

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switch(conifg-if)# no switchport

Enters global configuration mode.switch# configure terminal

Enters interface configuration mode.switch(config)# interface ethernet

Configures the interface as a Layer 3 interface and deletes any configuration specific to Layer 2 on this interface.

Configuring Layer 3 Interfaces

PurposeCommand or Action

Note

Configuring a Subinterface

To convert a Layer 3 interface back into a Layer 2 interface, use the switchport command.

Step 4

Configures an IP address for this interface.switch(config-if)# [ip | ipv6

]ip-address/length

Step 5

switch(config-if)# medium {broadcast | p2p}

(Optional) Configures the interface medium as either point to point or broadcast.

Note

The default setting is broadcast, and this setting does not appear in any of the show commands. However, if you do change the setting to p2p, you will see this setting when you enter the show running-config command.

Step 6

switch(config-if)# show interfaces

(Optional) Displays the Layer 3 interface statistics.

Step 7

switch(config-if)# copy running-config startup-config

(Optional) Saves the change persistently through reboots and restarts by copying the running configuration to the startup configuration.

This example shows how to configure an IPv4 routed Layer 3 interface:

switch# configure terminal switch(config)# interface ethernet 2/1 switch(config-if)# no switchport switch(config-if)# ip address 192.0.2.1/8 switch(config-if)# copy running-config startup-config

Configuring a Subinterface

Before You Begin

• Configure the parent interface as a routed interface.

• Create the port-channel interface if you want to create a subinterface on that port channel.

Procedure

PurposeCommand or Action

Step 1

switch(config-if)# copy running-config startup-config

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(Optional) Saves the change persistently through reboots and restarts by copying the running configuration to the startup configuration.

Configuring the Bandwidth on an Interface

Configuring Layer 3 Interfaces

PurposeCommand or Action

Step 2

switch(config)# interface ethernet

slot/port.number

Enters interface configuration mode. The range for the slot is from 1 to 255. The range for the port is from 1 to 128.

Step 3

Configures IP address for this interface.switch(config-if)# [ip | ipv6] address

ip-address/length

Step 4

switch(config-if)# encapsulation dot1Q vlan-id

Configures IEEE 802.1Q VLAN encapsulation on the subinterface. The range for the vlan-id is from 2 to

4093.

Step 5

switch(config-if)# show interfaces

(Optional) Displays the Layer 3 interface statistics.

Step 6

switch(config-if)# copy running-config startup-config

(Optional) Saves the change persistently through reboots and restarts by copying the running configuration to the startup configuration.

This example shows how to create a subinterface:

switch# configure terminal switch(config)# interface ethernet 2/1 switch(config-if)# ip address 192.0.2.1/8 switch(config-if)# encapsulation dot1Q 33 switch(config-if)# copy running-config startup-config

Configuring the Bandwidth on an Interface

You can configure the bandwidth for a routed interface, port channel, or subinterface.

Procedure

PurposeCommand or Action

Step 1

Step 2

Step 3

switch(config)# interface ethernet slot/port

switch(conifg-if)# bandwidth [value | inherit [value]]

Enters global configuration mode.switch# configure terminal

Enters interface configuration mode. The range for the slot is from 1 to 255. The range for the port is from 1 to 128.

Configures the bandwidth parameter for a routed interface, port channel, or subinterface, as follows:

•

value—Size of the bandwidth in kilobytes. The range is from 1 to 10000000.

• inherit—Indicates that all subinterfaces of this interface inherit either the bandwidth value (if a value is specified) or the bandwidth of the parent interface (if a value is not specified).

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Configuring Layer 3 Interfaces

Configuring a VLAN Interface

PurposeCommand or Action

Step 4

switch(config-if)# copy running-config startup-config

This example shows how to configure Ethernet interface 2/1 with a bandwidth value of 80000:

switch# configure terminal switch(config)# interface ethernet 2/1 switch(config-if)# bandwidth 80000 switch(config-if)# copy running-config startup-config

Configuring a VLAN Interface

Procedure

Step 1

Step 2

Step 3

switch(config)# interface vlan number

(Optional) Saves the change persistently through reboots and restarts by copying the running configuration to the startup configuration.

PurposeCommand or Action

Enters global configuration mode.switch# configure terminal

Enables VLAN interface mode.switch(config)# feature interface-vlan

Creates a VLAN interface. The number range is from 1 to 4094.

Step 4

Configures an IP address for this interface.switch(config-if)# [ip | ipv6 ] address

ip-address/length

Step 5

switch(config-if)# show interface vlan

number

(Optional) Displays the VLAN interface statistics. The number range is from 1 to 4094.

Step 6

switch(config-if)# copy running-config startup-config

(Optional) Saves the change persistently through reboots and restarts by copying the running configuration to the startup configuration.

This example shows how to create a VLAN interface:

switch# configure terminal switch(config)# feature interface-vlan switch(config)# interface vlan 10 switch(config-if)# ip address 192.0.2.1/8 switch(config-if)# copy running-config startup-config

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Configuring a Loopback Interface

Before You Begin

Ensure that the IP address of the loopback interface is unique across all routers on the network.

Procedure

Configuring Layer 3 Interfaces

PurposeCommand or Action

Step 1

Step 2

Step 3

Step 4

Step 5

This example shows how to create a loopback interface:

switch# configure terminal switch(config)# interface loopback 0 switch(config-if)# ip address 192.0.2.100/8 switch(config-if)# copy running-config startup-config

switch(config)# interface loopback

instance

ip-address/length

switch(config-if)# show interface loopback instance

switch(config-if)# copy running-config startup-config

Enters global configuration mode.switch# configure terminal

Creates a loopback interface. The instance range is from 0 to 1023.

Configures an IP address for this interface.switch(config-if)# [ip | ipv6 ] address

(Optional) Displays the loopback interface statistics. The instance range is from 0 to 1023.

(Optional) Saves the change persistently through reboots and restarts by copying the running configuration to the startup configuration.

Assigning an Interface to a VRF

Before You Begin

Assign the IP address for a tunnel interface after you have configured the interface for a VRF.

Procedure

PurposeCommand or Action

Step 1

Step 2

interface-typenumber

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Enters global configuration mode.switch# configure terminal

Enters interface configuration mode.switch(config)# interface

Configuring Layer 3 Interfaces

Verifying the Layer 3 Interfaces Configuration

PurposeCommand or Action

Step 3

Step 4

switch(conifg-if)#vrf member vrf-name

switch(config-if)# [ip | ipv6]ip-address/length

Adds this interface to a VRF.

Configures an IP address for this interface. You must do this step after you assign this interface to a VRF.

Step 5

Step 6

switch(config-if)# show vrf [vrf-name] interface interface-type number

switch(config-if)# show interfaces

(Optional) Displays VRF information.

(Optional) Displays the Layer 3 interface statistics.

Step 7

switch(config-if)# copy running-config startup-config

(Optional) Saves the change persistently through reboots and restarts by copying the running configuration to the startup configuration.

This example shows how to add a Layer 3 interface to the VRF:

switch# configure terminal switch(config)# interface loopback 0 switch(config-if)# vrf member RemoteOfficeVRF switch(config-if)# ip address 209.0.2.1/16 switch(config-if)# copy running-config startup-config

Verifying the Layer 3 Interfaces Configuration

Use one of the following commands to verify the configuration:

PurposeCommand

show interface ethernet slot/port

show interface ethernet slot/port brief

show interface ethernet slot/port capabilities

show interface ethernet slot/port description

show interface ethernet slot/port status

Displays the Layer 3 interface configuration, status, and counters (including the 5-minute exponentially decayed moving average of inbound and outbound packet and byte rates).

Displays the Layer 3 interface operational status.

Displays the Layer 3 interface capabilities, including port type, speed, and duplex.

Displays the Layer 3 interface description.

Displays the Layer 3 interface administrative status, port mode, speed, and duplex.

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Monitoring Layer 3 Interfaces

Configuring Layer 3 Interfaces

PurposeCommand

show interface ethernet slot/port.number

show interface port-channel channel-id.number

show interface loopback number

show interface loopback number brief

show interface loopback number description

show interface loopback number status

show interface vlan number

show interface vlan number brief

Displays the subinterface configuration, status, and counters (including the f-minute exponentially decayed moving average of inbound and outbound packet and byte rates).

Displays the port-channel subinterface configuration, status, and counters (including the 5-minute exponentially decayed moving average of inbound and outbound packet and byte rates).

Displays the loopback interface configuration, status, and counters.

Displays the loopback interface operational status.

Displays the loopback interface description.

Displays the loopback interface administrative status and protocol status.

Displays the VLAN interface configuration, status, and counters.

Displays the VLAN interface operational status.

show interface vlan number description

show interface vlan number private-vlan mapping

show interface vlan number status

Monitoring Layer 3 Interfaces

Use one of the following commands to display statistics about the feature:

show interface ethernet slot/port counters

show interface ethernet slot/port counters brief

Displays the VLAN interface description.

Displays the VLAN interface private VLAN information.

Displays the VLAN interface administrative status and protocol status.

PurposeCommand

Displays the Layer 3 interface statistics (unicast, multicast, and broadcast).

Displays the Layer 3 interface input and output counters.

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Configuring Layer 3 Interfaces

Configuration Examples for Layer 3 Interfaces

PurposeCommand

show interface ethernet slot/port counters detailed [all]

show interface ethernet slot/port counters error

show interface ethernet slot/port counters snmp

show interface ethernet slot/port.number counters

show interface port-channel channel-id.number counters

show interface loopback number counters

show interface loopback number counters detailed [all]

show interface loopback number counters errors

Displays the Layer 3 interface statistics. You can optionally include all 32-bit and 64-bit packet and byte counters (including errors).

Displays the Layer 3 interface input and output errors.

Displays the Layer 3 interface counters reported by SNMP MIBs. You cannot clear these counters.

Displays the subinterface statistics (unicast, multicast, and broadcast).

Displays the port-channel subinterface statistics (unicast, multicast, and broadcast).

Displays the loopback interface input and output counters (unicast, multicast, and broadcast).

Displays the loopback interface statistics. You can optionally include all 32-bit and 64-bit packet and byte counters (including errors).

Displays the loopback interface input and output errors.

show interface vlan number counters

Displays the VLAN interface input and output counters (unicast, multicast, and broadcast).

show interface vlan number counters detailed [all]

Displays the VLAN interface statistics. You can optionally include all Layer 3 packet and byte counters (unicast and multicast).

show interface vlan counters snmp

Displays the VLAN interface counters reported by SNMP MIBs. You cannot clear these counters.

Configuration Examples for Layer 3 Interfaces

This example shows how to configure Ethernet subinterfaces:

switch# configuration terminal switch(config)# interface ethernet 2/1.10 switch(config-if)# no switchport switch(config-if)# description Layer 3 for VLAN 10 switch(config-if)# encapsulation dot1q 10 switch(config-if)# ip address 192.0.2.1/8 switch(config-if)# copy running-config startup-config

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MIBs for Layer 3 Interfaces

IF-MIB

CISCO-IF-EXTENSION-MIB

ETHERLIKE-MIB

For details about command syntax, see the command reference for your device.

“Configuring IP” chapter in the Unicast Routing Configuration Guide for your device.

“Configuring VLANs” chapter in the Layer 2 Switching Configuration Guide for your device.

MIB LinkMIB

To locate and download MIBs, go to the following URL:

http://www.cisco.com/public/sw-center/netmgmt/ cmtk/mibs.shtml

Standards for Layer 3 Interfaces

No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.

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Configuring Port Channels

This chapter contains the following sections:

• Information About Port Channels, page 45

• Configuring Port Channels, page 54

• Verifying Port Channel Configuration, page 63

• Verifying the Load-Balancing Outgoing Port ID , page 64

Information About Port Channels

A port channel bundles individual interfaces into a group to provide increased bandwidth and redundancy. Port channeling also load balances traffic across these physical interfaces. The port channel stays operational as long as at least one physical interface within the port channel is operational.

You create an port channel by bundling compatible interfaces. You can configure and run either static port channels or port channels running the Link Aggregation Control Protocol (LACP).

Any configuration changes that you apply to the port channel are applied to each member interface of that port channel. For example, if you configure Spanning Tree Protocol (STP) parameters on the port channel, Cisco NX-OS applies those parameters to each interface in the port channel.

You can use static port channels, with no associated protocol, for a simplified configuration. For more efficient use of the port channel, you can use the Link Aggregation Control Protocol (LACP), which is defined in IEEE

802.3ad. When you use LACP, the link passes protocol packets.

CHAPTER 4

Understanding Port Channels

Using port channels, Cisco NX-OS provides wider bandwidth, redundancy, and load balancing across the channels.

You can collect ports into a static port channel or you can enable the Link Aggregation Control Protocol (LACP). Configuring port channels with LACP requires slightly different steps than configuring static port

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Guidelines and Limitations for Port Channel Configuration

channels. For information on port channel configuration limits, see the Verified Scalability document for your platform. For more information about load balancing, see Load Balancing Using Port Channels, on page 48.

Cisco NX-OS does not support Port Aggregation Protocol (PAgP) for port channels.Note

A port channel bundles individual links into a channel group to create a single logical link that provides the aggregate bandwidth of several physical links. If a member port within a port channel fails, traffic previously carried over the failed link switches to the remaining member ports within the port channel.

Each port can be in only one port channel. All the ports in an port channel must be compatible; they must use the same speed and operate in full-duplex mode. When you are running static port channels, without LACP, the individual links are all in the on channel mode; you cannot change this mode without enabling LACP.

You cannot change the mode from ON to Active or from ON to Passive.Note

You can create a port channel directly by creating the port-channel interface, or you can create a channel group that acts to aggregate individual ports into a bundle. When you associate an interface with a channel group, Cisco NX-OS creates a matching port channel automatically if the port channel does not already exist. You can also create the port channel first. In this instance, Cisco NX-OS creates an empty channel group with the same channel number as the port channel and takes the default configuration.

Configuring Port Channels

Note

A port channel is operationally up when at least one of the member ports is up and that port’s status is channeling. The port channel is operationally down when all member ports are operationally down.

Guidelines and Limitations for Port Channel Configuration

Port channels can be configured in one of two ways: either in global configuration mode or in switch profile mode. Consider the following guidelines and limitations when configuring port channels via the configuration synchronization feature in Cisco NX-OS:

• Once a port channel is configured using switch profile mode, it cannot be configured using global configuration (config terminal) mode.

Note

• Shutdown and no shutdown can be configured in either global configuration mode or switch profile mode.

Several port channel sub-commands are not configurable in switch profile mode. These commands can be configured from global configuration mode even if the port channel is created and configured in switch profile mode.

For example, the following command can only be configured in global configuration mode:

switchport private-vlan association trunk primary-vlan secondary-vlan

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Configuring Port Channels

• If a port channel is created in global configuration mode, channel groups including member interfaces must also be created using global configuration mode.

• Port channels that are configured within switch profile mode may have members both inside and outside of a switch profile.

• If you want to import a member interface to a switch profile, the port channel that corresponds with the member interface must also be present within the switch profile.

For more information on switch profiles, see the .

Compatibility Requirements

When you add an interface to a port channel group, Cisco NX-OS checks certain interface attributes to ensure that the interface is compatible with the channel group. Cisco NX-OS also checks a number of operational attributes for an interface before allowing that interface to participate in the port-channel aggregation.

The compatibility check includes the following operational attributes:

• Port mode

Compatibility Requirements

• Access VLAN

• Trunk native VLAN

• Allowed VLAN list

• Speed

• 802.3x flow control setting

• MTU

The Cisco Nexus device only supports system level MTU. This attribute cannot be changed on an individual port basis.

• Broadcast/Unicast/Multicast Storm Control setting

• Priority-Flow-Control

• Untagged CoS

Use the show port-channel compatibility-parameters command to see the full list of compatibility checks that Cisco NX-OS uses.

You can only add interfaces configured with the channel mode set to on to static port channels. You can also only add interfaces configured with the channel mode as active or passive to port channels that are running LACP. You can configure these attributes on an individual member port.

When the interface joins a port channel, the following individual parameters are replaced with the values on the port channel:

• Bandwidth

• MAC address

• Spanning Tree Protocol

The following interface parameters remain unaffected when the interface joins a port channel:

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Load Balancing Using Port Channels

• Description

• CDP

• LACP port priority

• Debounce

After you enable forcing a port to be added to a channel group by entering the channel-group force command, the following two conditions occur:

• When an interface joins a port channel the following parameters are removed and they are operationally replaced with the values on the port channel; however, this change will not be reflected in the running-configuration for the interface:

• QoS

• Bandwidth

• Delay

• STP

Configuring Port Channels

• Service policy

• ACLs

• When an interface joins or leaves a port channel, the following parameters remain unaffected:

• Beacon

• Description

• CDP

• LACP port priority

• Debounce

• UDLD

• Shutdown

• SNMP traps

Load Balancing Using Port Channels

Cisco NX-OS load balances traffic across all operational interfaces in a port channel by reducing part of the binary pattern formed from the addresses in the frame to a numerical value that selects one of the links in the channel. Port channels provide load balancing by default.

The basic configuration uses the following criteria to select the link:

• For a Layer 2 frame, it uses the source and destination MAC addresses.

• For a Layer 3 frame, it uses the source and destination MAC addresses and the source and destination IP addresses.

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Load Balancing Using Port Channels

• For a Layer 4 frame, it uses the source and destination MAC addresses and the source and destination IP addresses.

Note

You have the option to include the source and destination port number for the Layer 4 frame.

You can configure the switch to use one of the following methods (see the following table for more details) to load balance across the port channel:

• Destination MAC address

• Source MAC address

• Source and destination MAC address

• Destination IP address

• Source IP address

• Source and destination IP address

• Destination TCP/UDP port number

• Source TCP/UDP port number

• Source and destination TCP/UDP port number

Table 4: Port Channel Load-Balancing Criteria

Layer 4 CriteriaLayer 3 CriteriaLayer 2 CriteriaConfiguration

Source and destination MAC

Source and destination IP

port

Source and destination MAC

Destination MACDestination IP

Source and destination MAC

Destination MACDestination TCP/UDP

Source and destination MAC

Destination MAC, destination IP

Source and destination MAC, source and destination IP

Destination MAC, destination IP

Source MAC, source IPSource MACSource TCP/UDP port

Destination MACDestination MACDestination MACDestination MAC

Source MACSource MACSource MACSource MAC

Source and destination MAC

Destination MAC, destination IP

Source MAC, source IPSource MAC, source IPSource MACSource IP

Source and destination MAC, source and destination IP

Destination MAC, destination IP, destination port

Source MAC, source IP, source port

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Configuring Port Channels

Layer 4 CriteriaLayer 3 CriteriaLayer 2 CriteriaConfiguration

Source and destination TCP/UDP port

Source and destination MAC

Source and destination MAC, source and destination IP

Source and destination MAC, source and destination IP, source and destination port

Fabric Extenders are not configurable individually. Fabric extender configurations are defined on the Cisco Nexus device. In the case of the port-channel load balancing protocol, the table below illustrates which port-channel load balancing option is automatically configured on the fabric extender modules as a result of the configuration performed on the Cisco Nexus device.

The following table shows the criteria used for each configuration:

Table 5: Port channel Load-Balancing Criteria for the Cisco Nexus 2232 and Cisco Nexus 2248 Fabric Extenders

Layer 4 CriteriaLayer 3 CriteriaLayer 2 CriteriaConfiguration

Destination MAC

Source MAC

Source and destination MAC

Destination IP

Source IP

Source and destination IP

Destination TCP/UDP port

Source TCP/UDP port

Source and destination MAC

Source and destination MAC, and source and destination IP

Source and destination MAC, source and destination IP , and source and destination port

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Understanding LACP

Layer 4 CriteriaLayer 3 CriteriaLayer 2 CriteriaConfiguration

Source and destination TCP/UDP port

Use the option that provides the balance criteria with the greatest variety in your configuration. For example, if the traffic on a port channel is going only to a single MAC address and you use the destination MAC address as the basis of port-channel load balancing, the port channel always chooses the same link in that port channel; using source addresses or IP addresses might result in better load balancing.

Understanding LACP

LACP Overview

You must enable the LACP feature before you can configure and use LACP functions.Note

The following figure shows how individual links can be combined into LACP port channels and channel groups as well as function as individual links.

Source and destination MAC

Source and destination MAC, source and destination IP

Source and destination MAC, source and destination IP , and source and destination port

Note

Figure 4: Individual Links Combined into a Port channel

With LACP, just like with static port-channels, you can bundle up to 16 interfaces in a channel group.

When you delete the port channel, Cisco NX-OS automatically deletes the associated channel group. All member interfaces revert to their previous configuration.

You cannot disable LACP while any LACP configurations are present.

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Understanding LACP

LACP ID Parameters

LACP uses the following parameters:

• LACP system priority—Each system that runs LACP has an LACP system priority value. You can accept the default value of 32768 for this parameter, or you can configure a value between 1 and 65535. LACP uses the system priority with the MAC address to form the system ID and also uses the system priority during negotiation with other devices. A higher system priority value means a lower priority.

The LACP system ID is the combination of the LACP system priority value and the MAC address.Note

• LACP port priority—Each port configured to use LACP has an LACP port priority. You can accept the default value of 32768 for the LACP port priority, or you can configure a value between 1 and 65535. LACP uses the port priority with the port number to form the port identifier. LACP uses the port priority to decide which ports should be put in standby mode when there is a limitation that prevents all compatible ports from aggregating and which ports should be put into active mode. A higher port priority value means a lower priority for LACP. You can configure the port priority so that specified ports have a lower priority for LACP and are most likely to be chosen as active links, rather than hot-standby links.

Configuring Port Channels

Channel Modes

Individual interfaces in port channels are configured with channel modes. When you run static port channels, with no protocol, the channel mode is always set to on. After you enable LACP globally on the device, you enable LACP for each channel by setting the channel mode for each interface to active or passive. You can configure either channel mode for individual links in the LACP channel group.

Note

You must enable LACP globally before you can configure an interface in either the active or passive channel mode.

The following table describes the channel modes.

• LACP administrative key—LACP automatically configures an administrative key value equal to the channel-group number on each port configured to use LACP. The administrative key defines the ability of a port to aggregate with other ports. A port’s ability to aggregate with other ports is determined by these factors:

◦ Port physical characteristics, such as the data rate, the duplex capability, and the point-to-point or

shared medium state

◦ Configuration restrictions that you establish

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Understanding LACP

Table 6: Channel Modes for Individual Links in a Port channel

DescriptionChannel Mode

passive

LACP mode that places a port into a passive negotiating state, in which the port responds to LACP packets that it receives but does not initiate LACP negotiation.

active

LACP mode that places a port into an active negotiating state, in which the port initiates negotiations with other ports by sending LACP packets.

All static port channels, that is, that are not running LACP, remain in this mode. If you attempt to change the channel mode to active or passive before enabling LACP, the device returns an error message.

You enable LACP on each channel by configuring the interface in that channel for the channel mode as either active or passive. When an LACP attempts to negotiate with an interface in the on state, it does not receive any LACP packets and becomes an individual link with that interface; it does not join the LACP channel group.

Both the passive and active modes allow LACP to negotiate between ports to determine if they can form a port channel, based on criteria such as the port speed and the trunking state. The passive mode is useful when you do not know whether the remote system, or partner, supports LACP.

Ports can form an LACP port channel when they are in different LACP modes as long as the modes are compatible as in the following examples:

• A port in active mode can form a port channel successfully with another port that is in active mode.

• A port in active mode can form a port channel with another port in passive mode.

• A port in passive mode cannot form a port channel with another port that is also in passive mode because neither port will initiate negotiation.

• A port in on mode is not running LACP.

LACP Marker Responders

Using port channels, data traffic may be dynamically redistributed due to either a link failure or load balancing. LACP uses the Marker Protocol to ensure that frames are not duplicated or reordered because of this redistribution. Cisco NX-OS supports only Marker Responders.

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Configuring Port Channels

LACP-Enabled and Static Port Channel Differences

The following table provides a brief summary of major differences between port channels with LACP enabled and static port channels. For information about the maximum configuration limits, see the Verified Scalability document for your device.

Table 7: Port channels with LACP Enabled and Static Port channels

Configuring Port Channels

Static Port ChannelsPort Channels with LACP EnabledConfigurations

Not applicable.Enable globally.Protocol applied

Channel mode of links

Configuring Port Channels

Creating a Port Channel

You can create a port channel before creating a channel group. Cisco NX-OS automatically creates the associated channel group.

If you want LACP-based port channels, you need to enable LACP.Note

Procedure

Can only be On.Can be either:

• Active

• Passive

PurposeCommand or Action

Step 1

Step 2

Step 3

This example shows how to create a port channel:

switch# configure terminal switch (config)# interface port-channel 1

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switch(config)# interface port-channel

channel-number

switch(config)# no interface port-channel channel-number

Enters configuration mode.switch# configure terminal

Specifies the port-channel interface to configure, and enters the interface configuration mode. The range is from 1 to 4096. Cisco NX-OS automatically creates the channel group if it does not already exist.

Removes the port channel and deletes the associated channel group.

Configuring Port Channels

Adding a Port to a Port Channel

You can add a port to a new channel group or to a channel group that already contains ports. Cisco NX-OS creates the port channel associated with this channel group if the port channel does not already exist.

If you want LACP-based port channels, you need to enable LACP.Note

Procedure

Adding a Port to a Port Channel

PurposeCommand or Action

Step 1

Step 2

Step 3

Step 4

switch(config)# interface type slot/port

switch(config-if)# switchport mode trunk

switch(config-if)# switchport trunk {allowed vlan vlan-id | native vlan

Enters configuration mode.switch# configure terminal

Specifies the interface that you want to add to a channel group and enters the interface configuration mode.

(Optional) Configures the interface as a trunk port.

(Optional) Configures necessary parameters for a trunk port.

vlan-id}

Step 5

switch(config-if)# channel-group

channel-number

Configures the port in a channel group and sets the mode. The channel-number range is from 1 to 4096. Cisco NX-OS creates the port channel associated with this channel group if the port channel does not already exist. This is called implicit port channel creation.

Step 6

switch(config-if)# no channel-group

(Optional) Removes the port from the channel group. The port reverts to its original configuration.

This example shows how to add an Ethernet interface 1/4 to channel group 1:

switch# configure terminal switch (config)# interface ethernet 1/4 switch(config-if)# switchport mode trunk switch(config-if)# channel-group 1

Configuring Load Balancing Using Port Channels

You can configure the load-balancing algorithm for port channels that applies to the entire device.

If you want LACP-based port channels, you need to enable LACP.Note

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Configuring Load Balancing Using Port Channels

Procedure

Configuring Port Channels

PurposeCommand or Action

Step 1

Step 2

switch(config)# port-channel load-balance ethernet {[destination-ip | destination-mac | destination-port | source-dest-ip | source-dest-mac | source-dest-port | source-ip | source-mac | source-port]

crc-poly}

Enters configuration mode.switch# configure terminal

Specifies the load-balancing algorithm for the device. The range depends on the device. The default is source-dest-mac.

Beginning with Cisco NX-OS Release 5.0(3)N2(1), the Cisco Nexus 5500 Platform switches support 8 hash polynomials that can be used for compression on the hash-parameters. Depending on variations in the hash parameters for egress traffic flows from a port channel, different polynomials could provide different load distribution results. The default hash polynomial is CRC8a. The variable can be configured as follows:

• CRC8a

• CRC8b

• CRC8c

• CRC8d

• CRC8e

• CRC8f

• CRC8g

Note

Step 3

switch(config)# no port-channel load-balance ethernet

(Optional) Restores the default load-balancing algorithm of source-dest-mac.

Step 4

switch# show port-channel load-balance

(Optional) Displays the port-channel load-balancing algorithm.

This example shows how to configure source IP load balancing for port channels:

switch# configure terminal switch (config)# port-channel load-balance ethernet source-ip

Before Release 4.0(1a)N1 of Cisco NX-OS, the source-dest-ip, source-dest-mac, and source-dest-port keywords were source-destination-ip, source-destination-mac, and source-destination-port, respectively.

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Configuring Port Channels

Configuring Hardware Hashing for Multicast Traffic

By default, ingress multicast traffic on any port in the switch selects a particular port channel member to egress the traffic. You can configure hardware hashing for multicast traffic to reduce potential bandwidth issues and to provide effective load balancing of the ingress multicast traffic. Use the hardware multicast

hw-hash command to enable hardware hashing. To restore the default, use the no hardware multicast hw-hash command.

Procedure

PurposeCommand or Action

Enabling LACP

Step 1

Step 2

Step 3

switch(config)# interface port-channel

channel-number

switch(config-if)# hardware multicast hw-hash

Enters configuration mode.switch# configure terminal

Selects the port channel and enters the interface configuration mode.

Configures hardware hashing for the specified port channel.

This example shows how to configure hardware hashing on a port channel:

switch# configure terminal switch (config)# interface port-channel 21 switch(config-if)# hardware multicast hw-hash

This example shows how to remove hardware hashing from a port channel:

switch# configure terminal switch (config)# interface port-channel 21 switch(config-if)# no hardware multicast hw-hash

LACP is disabled by default; you must enable LACP before you begin LACP configuration. You cannot disable LACP while any LACP configuration is present.

LACP learns the capabilities of LAN port groups dynamically and informs the other LAN ports. Once LACP identifies correctly matched Ethernet links, it facilitates grouping the links into an port channel. The port channel is then added to the spanning tree as a single bridge port.

Procedure

PurposeCommand or Action

Step 1

Step 2

Step 3

switch(config)# show feature

Enters configuration mode.switch# configure terminal

Enables LACP on the switch.switch(config)# feature lacp

(Optional) Displays enabled features.

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Configuring the Channel Mode for a Port

This example shows how to enable LACP:

switch# configure terminal switch(config)# feature lacp

Configuring the Channel Mode for a Port

You can configure the channel mode for each individual link in the LACP port channel as active or passive. This channel configuration mode allows the link to operate with LACP.

When you configure port channels with no associated protocol, all interfaces on both sides of the link remain in the on channel mode.

Before You Begin

Ensure that you have enabled the LACP feature.

Configuring Port Channels

Procedure

Step 1

Step 2

Step 3

switch(config)# interface type slot/port

switch(config-if)#

channel-group

channel-number [force] [mode {on | active | passive}]

PurposeCommand or Action

Enters configuration mode.switch# configure terminal

Specifies the interface to configure, and enters the interface configuration mode.

Specifies the port mode for the link in a port channel. After LACP is enabled, you configure each link or the entire channel as active or passive.

force—Specifies that the LAN port be forcefully added to the channel group. This option is available in Cisco NX-OS Release

5.0(2)N2(1).

mode—Specifies the port channel mode of the interface.

active—Specifies that when you enable LACP, this command enables LACP on the specified interface. The interface is in an active negotiating state in which the port initiates negotiations with other ports by sending LACP packets.

on—(Default mode) Specifies that all port channels that are not running LACP remain in this mode.

passive—Enables LACP only if an LACP device is detected. The interface is in a passive negotiation state in which the port responds to LACP packets that it receives but does not initiate LACP negotiation.

When you run port channels with no associated protocol, the channel mode is always on.

Step 4

Returns the port mode to on for the specified interface.switch(config-if)# no

channel-group number mode

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Configuring Port Channels

This example shows how to set the LACP-enabled interface to active port-channel mode for Ethernet interface 1/4 in channel group 5:

switch# configure terminal switch (config)# interface ethernet 1/4 switch(config-if)# channel-group 5 mode active

This example shows how to forcefully add an interface to the channel group 5:

switch(config)# interface ethernet 1/1 switch(config-if)# channel-group 5 force switch(config-if)#

Configuring the LACP Fast Timer Rate

You can change the LACP timer rate to modify the duration of the LACP timeout. Use the lacp rate command to set the rate at which LACP control packets are sent to an LACP-supported interface. You can change the timeout rate from the default rate (30 seconds) to the fast rate (1 second). This command is supported only on LACP-enabled interfaces.

Configuring the LACP Fast Timer Rate

Before You Begin

Ensure that you have enabled the LACP feature.

Procedure

PurposeCommand or Action

Step 1

Step 2

switch(config)# interface type slot/port

Enters configuration mode.switch# configure terminal

Specifies the interface to configure and enters the interface configuration mode.

Step 3

switch(config-if)# lacp rate fast

Configures the fast rate (one second) at which LACP control packets are sent to an LACP-supported interface.

This example shows how to configure the LACP fast rate on Ethernet interface 1/4:

switch# configure terminal switch (config)# interface ethernet 1/4

switch(config-if)# lacp rate fast

This example shows how to restore the LACP default rate (30 seconds) on Ethernet interface 1/4.

switch# configure terminal switch (config)# interface ethernet 1/4 switch(config-if)# no lacp rate fast

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Configuring the LACP System Priority and System ID

The LACP system ID is the combination of the LACP system priority value and the MAC address.

Before You Begin

Ensure that you have enabled the LACP feature.

Procedure

PurposeCommand or Action

Configuring Port Channels

Step 1

Step 2

Step 3

This example shows how to set the LACP system priority to 2500:

switch# configure terminal switch(config)# lacp system-priority 2500

switch(config)# lacp system-priority

priority

switch# show lacp system-identifier

Configuring the LACP Port Priority

You can configure each link in the LACP port channel for the port priority.

Before You Begin

Ensure that you have enabled the LACP feature.

Procedure

Enters configuration mode.switch# configure terminal

Configures the system priority for use with LACP. Valid values are 1 through 65535, and higher numbers have lower priority. The default value is 32768.

(Optional) Displays the LACP system identifier.

PurposeCommand or Action

Step 1

Step 2

Step 3

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switch(config)# interface type slot/port

switch(config-if)# lacp port-priority

priority

Enters configuration mode.switch# configure terminal

Specifies the interface to configure, and enters the interface configuration mode.

Configures the port priority for use with LACP. Valid values are 1 through 65535, and higher numbers have lower priority. The default value is 32768.

Configuring Port Channels

This example shows how to set the LACP port priority for Ethernet interface 1/4 to 40000:

switch# configure terminal switch (config)# interface ethernet 1/4 switch(config-if)# lacp port priority 40000

Disabling LACP Graceful Convergence

Before You Begin

• Enable the LACP feature.

• Confirm that the port channel is in the administratively down state.

• Ensure that you are in the correct VDC. To switch to the correct VDC, enter the switchto vdc command.

Procedure

Disabling LACP Graceful Convergence

Step 1

Step 2

Step 3

Step 4

Step 5

Example:

switch# configure terminal switch(config)#

interface port-channel number

Example:

switch(config)# interface port-channel 1 switch(config) #

Example:

switch(config-if)# shutdown switch(config-if) #

no lacp graceful-convergence

Example:

switch(config-if)# no lacp graceful-convergence switch(config-if) #

PurposeCommand or Action

Enters global configuration mode.configure terminal

Specifies the port channel interface to configure, and enters interface configuration mode.

Administratively shuts down the port channel.shutdown

Disables LACP graceful convergence on the specified port channel.

Administratively brings the port channel up.no shutdown

Example:

switch(config-if)# no shutdown switch(config-if) #

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Reenabling LACP Graceful Convergence

Configuring Port Channels

PurposeCommand or Action

Step 6

copy running-config startup-config

Example:

switch(config-if)# copy running-config startup-config

The following example disables LACP graceful convergence on a port channel:

switch# configure terminal switch(config) # interface port-channel 1 switch(config-if) # shutdown switch(config-if) # no lacp graceful-convergence switch(config-if) # no shutdown switch(config-if) #

Reenabling LACP Graceful Convergence

Before You Begin

• Enable the LACP feature.

• Confirm that the port channel is in the administratively down state.

• Ensure that you are in the correct VDC. To switch to the correct VDC, enter the switchto vdc command.

(Optional) Saves the change persistently through reboots and restarts by copying the running configuration to the startup configuration.

Procedure

Step 1

Step 2

Step 3

Example:

switch# configure terminal switch(config)#

interface port-channel number

Example:

switch(config)# interface port-channel 1 switch(config) #

Example:

switch(config-if)# shutdown switch(config-if) #

PurposeCommand or Action

Enters global configuration mode.configure terminal

Specifies the port channel interface to configure, and enters interface configuration mode.

Administratively shuts down the port channel.shutdown

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Verifying Port Channel Configuration

PurposeCommand or Action

Step 4

lacp graceful-convergence

Enables LACP graceful convergence on the specified port channel.

Example:

switch(config-if)# lacp graceful-convergence switch(config-if) #

Step 5

Step 6

Example:

switch(config-if)# no shutdown switch(config-if) #

copy running-config startup-config

Administratively brings the port channel up.no shutdown

(Optional) Saves the change persistently through reboots

Example:

switch(config-if)# copy running-config startup-config

and restarts by copying the running configuration to the startup configuration.

The following example disables LACP graceful convergence on a port channel:

switch# configure terminal switch(config) # interface port-channel 1 switch(config-if) # shutdown switch(config-if) # lacp graceful-convergence switch(config-if) # no shutdown switch(config-if) #

Verifying Port Channel Configuration

To display port channel configuration information, perform one of the following tasks:

channel-number

switch# show resource

switch# show lacp {counters | interface type

slot/port | neighbor | port-channel | system-identifier}

switch# show port-channel compatibility-parameters

switch# show port-channel database [interface port-channel channel-number]

PurposeCommand

Displays the status of a port channel interface.switch# show interface port-channel

Displays enabled features.switch# show feature

Displays the number of resources currently available in the system.

Displays LACP information.

Displays the parameters that must be the same among the member ports in order to join a port channel.

Displays the aggregation state for one or more port-channel interfaces.

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Verifying the Load-Balancing Outgoing Port ID

Configuring Port Channels

PurposeCommand

Displays a summary for the port channel interfaces.switch# show port-channel summary

Displays the traffic statistics for port channels.switch# show port-channel traffic

switch# show port-channel usage

Displays the range of used and unused channel numbers.

switch# show port-channel database

Displays information on current running of the port channel feature.

switch# show port-channel load-balance

Displays information about load-balancing using port channels.

Verifying the Load-Balancing Outgoing Port ID

Command Guidelines

The show port-channel load-balance command allows you to verify which ports a given frame is hashed to on a port channel. You need to specify the VLAN and the destination MAC in order to get accurate results.

Certain traffic flows are not subject to hashing, for example when there is a single port in a port-channel.Note

To display the load-balancing outgoing port ID, perform one of the tasks listed in the table below.

PurposeCommand

Displays the outgoing port ID.switch# show port-channel load-balance

forwarding-path interface port-channel port-channel-id vlan vlan-id dst-ip src-ip dst-mac src-mac l4-src-port port-id l4-dst-port port-id

Example

This example shows the output of the short port-channel load-balance command.

switch# show port-channel load-balance forwarding-path interface port-channel 10 vlan 1 dst-ip 1.225.225.225 src-ip 1.1.10.10 src-mac aa:bb:cc:dd:ee:ff l4-src-port 0 l4-dst-port 1

Missing params will be substituted by 0's. Load-balance Algorithm on switch: source-dest-port

crc8_hash:204 Outgoing port id: Ethernet 1/1 Param(s) used to calculate load balance: dst-port: 0 src-port: 0 dst-ip: 1.225.225.225 src-ip: 1.1.10.10 dst-mac: 0000.0000.0000 src-mac: aabb.ccdd.eeff

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Configuring Virtual Port Channels

This chapter contains the following sections:

• Information About vPCs, page 65

• Guidelines and Limitations for vPCs, page 79

• Configuring vPCs, page 80

• Configuring the vPC Peer Switch, page 93

• Verifying the vPC Configuration, page 95

• vPC Example Configurations, page 101

• vPC Default Settings, page 105

Information About vPCs

CHAPTER 5

vPC Overview

A virtual port channel (vPC) allows links that are physically connected to two different Cisco Nexus devices or Cisco Nexus Fabric Extenders to appear as a single port channel by a third device (see the following figure). The third device can be a switch, server, or any other networking device. You can configure vPCs in topologies that include Cisco Nexus devices connected to Cisco Nexus Fabric Extenders. A vPC can provide multipathing,

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which allows you to create redundancy by enabling multiple parallel paths between nodes and load balancing traffic where alternative paths exist.

Figure 5: vPC Architecture

You configure the EtherChannels by using one of the following:

• No protocol

• Link Aggregation Control Protocol (LACP)

When you configure the EtherChannels in a vPC—including the vPC peer link channel—each switch can have up to 16 active links in a single EtherChannel. When you configure a vPC on a Fabric Extender, only one port is allowed in an EtherChannel.

You must enable the vPC feature before you can configure or run the vPC functionality.Note

To enable the vPC functionality, you must create a peer-keepalive link and a peer-link under the vPC domain for the two vPC peer switches to provide the vPC functionality.

To create a vPC peer link you configure an EtherChannel on one Cisco Nexus device by using two or more Ethernet ports. On the other switch, you configure another EtherChannel again using two or more Ethernet ports. Connecting these two EtherChannels together creates a vPC peer link.

We recommend that you configure the vPC peer-link EtherChannels as trunks.Note

The vPC domain includes both vPC peer devices, the vPC peer-keepalive link, the vPC peer link, and all of the EtherChannels in the vPC domain connected to the downstream device. You can have only one vPC domain ID on each vPC peer device.

Always attach all vPC devices using EtherChannels to both vPC peer devices.Note

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Terminology

vPC Terminology

Terminology

A vPC provides the following benefits:

• Allows a single device to use an EtherChannel across two upstream devices

• Eliminates Spanning Tree Protocol (STP) blocked ports

• Provides a loop-free topology

• Uses all available uplink bandwidth

• Provides fast convergence if either the link or a switch fails

• Provides link-level resiliency

• Assures high availability

The terminology used in vPCs is as follows:

• vPC—The combined EtherChannel between the vPC peer devices and the downstream device.

• vPC peer device—One of a pair of devices that are connected with the special EtherChannel known as the vPC peer link.

• vPC peer link—The link used to synchronize states between the vPC peer devices.

• vPC member port—Interfaces that belong to the vPCs.

• Host vPC port—Fabric Extender host interfaces that belong to a vPC.

• vPC domain—This domain includes both vPC peer devices, the vPC peer-keepalive link, and all of the port channels in the vPC connected to the downstream devices. It is also associated to the configuration mode that you must use to assign vPC global parameters. The vPC domain ID must be the same on both switches.

• vPC peer-keepalive link—The peer-keepalive link monitors the vitality of a vPC peer Cisco Nexus device. The peer-keepalive link sends configurable, periodic keepalive messages between vPC peer devices.

No data or synchronization traffic moves over the vPC peer-keepalive link; the only traffic on this link is a message that indicates that the originating switch is operating and running vPCs.

Fabric Extender Terminology

The terminology used for the Cisco Nexus Fabric Extender is as follows:

• Fabric interface—A 10-Gigabit Ethernet uplink port designated for connection from the Fabric Extender to its parent switch. A fabric interface cannot be used for any other purpose. It must be directly connected to the parent switch.

• EtherChannel fabric interface—An EtherChannel uplink connection from the Fabric Extender to its parent switch. This connection consists of fabric interfaces bundled into a single logical channel.

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• Host interface—An Ethernet interface for server or host connectivity. These ports are 1-Gigabit Ethernet interfaces or 10-Gigabit Ethernet interfaces, depending on the fabric extender model.

• EtherChannel host interface—An EtherChannel downlink connection from the Fabric Extender host interface to a server port.

Note

An EtherChannel host interface consists of only one host interface and can be configured either as a Link Aggregation Control Protocol (LACP) or non-LACP EtherChannel.

Supported vPC Topologies

Cisco Nexus 5000 Series Switch vPC Topology

You can connect a pair of Cisco Nexus 5000 Series switches or a pair of Cisco Nexus 5500 Series switches in a vPC directly to another switch or to a server. vPC peer switches must be of the same type, for example, you can connect a pair of Nexus 5000 series switches or a pair of Nexus 5500 Series switches but you cannot connect a Nexus 5000 Series switch to a Nexus 5500 Series switch in a vPC topology. Up to 8 interfaces could be connected to each Cisco Nexus 5000 Series switch providing 16 interfaces bundled for the vPC pair. The topology that is shown in the following figure provides the vPC functionality to dual connected switches or servers with 10-Gigabit or 1-Gigabit Ethernet uplink interfaces.

Figure 6: Switch-to-Switch vPC Topology

Note

The first 8 ports on the Cisco Nexus 5010 switch and the first 16 ports on the Cisco Nexus 5020 switch are switchable 1-Gigabit and 10-Gigabit ports. You can enable vPC functionality on these ports in 1-Gigabit mode.

The switch connected to the pair of Cisco Nexus 5000 Series switches can be any standards-based Ethernet switch. Common environments to use this configuration include Blade Chassis with dual switches connected to the pair of Cisco Nexus 5000 Series switches through vPC or Unified Computing Systems connected to the pair of Cisco Nexus 5000 Series switches.

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Single Homed Fabric Extender vPC Topology

You can connect a server with dual or quad or more network adapters that are configured in a vPC to a pair of Cisco Nexus Fabric Extenders which are connected to the Cisco Nexus devices as depicted. Depending on the FEX model, you may be able to connect one or more network adapter interfaces to each fabric extender. As an example, the following figure refers to a topology built with the Cisco Nexus 2148T fabric extender, where a server has one link only to each fabric extender. A topology with Cisco Nexus 2248TP or with Cisco Nexus 2232PP fabric extender could consist of more links from the server to a single fabric extender.

. The topology that is shown in the following figure provides the vPC functionality to dual homed servers with 1-Gigabit Ethernet uplink interfaces.

Figure 7: Single Homed Fabric Extender vPC Topology

Supported vPC Topologies

Note

The Cisco Nexus device can support up to 12 configured single homed Fabric Extenders (576 ports) with this topology however only 480 576 dual homed host servers can be configured in a vPCs with this configuration.

The Cisco Nexus 2148T fabric extender does not support EtherChannels on its host interfaces. Therefore a maximum of two links can be configured in an EtherChannel from the server where each link is connected to a separate Fabric Extender.

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Dual Homed Fabric Extender vPC Topology

You can connect the Cisco Nexus Fabric Extender to two upstream Cisco Nexus devices and downstream to a number of single homed servers. The topology shown in the following figure provides the vPC functionality to singly connected servers with 1-Gigabit Ethernet uplink interfaces.

Figure 8: Dual Homed Fabric Extender vPC Topology

Configuring Virtual Port Channels

vPC Domain

The Cisco Nexus device can support up to 12 configured dual homed Fabric Extenders with this topology. A maximum of 576 single homed servers can be connected to this configuration.

To create a vPC domain, you must first create a vPC domain ID on each vPC peer switch using a number from 1 to 1000. This ID must be the same on a set of vPC peer devices.

You can configure the EtherChannels and vPC peer links by using LACP or no protocol. When possible, we recommend that you use LACP on the peer-link, because LACP provides configuration checks against a configuration mismatch on the EtherChannel.

The vPC peer switches use the vPC domain ID that you configure to automatically assign a unique vPC system MAC address. Each vPC domain has a unique MAC address that is used as a unique identifier for the specific vPC-related operations, although the switches use the vPC system MAC addresses only for link-scope operations, such as LACP. We recommend that you create each vPC domain within the contiguous network with a unique domain ID. You can also configure a specific MAC address for the vPC domain, rather than having the Cisco NX-OS software assign the address.

The vPC peer switches use the vPC domain ID that you configure to automatically assign a unique vPC system MAC address. The switches use the vPC system MAC addresses only for link-scope operations, such as LACP or BPDUs. You can also configure a specific MAC address for the vPC domain.

Cisco recommends that you configure the same VPC domain ID on both peers and, the domain ID should be unique in the network. For example, if there are two different VPCs (one in access and one in aggregation) then each vPC should have a unique domain ID.

After you create a vPC domain, the Cisco NX-OS software automatically creates a system priority for the vPC domain. You can also manually configure a specific system priority for the vPC domain.

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Peer-Keepalive Link and Messages

Note

If you manually configure the system priority, you must ensure that you assign the same priority value on both vPC peer switches. If the vPC peer switches have different system priority values, the vPC will not come up.

Peer-Keepalive Link and Messages

The Cisco NX-OS software uses a peer-keepalive link between the vPC peers to transmit periodic, configurable keepalive messages. You must have Layer 3 connectivity between the peer switches to transmit these messages; the system cannot bring up the vPC peer link unless a peer-keepalive link is already up and running.

If one of the vPC peer switches fails, the vPC peer switch on the other side of the vPC peer link senses the failure when it does not receive any peer-keepalive messages. The default interval time for the vPC peer-keepalive message is 1 second. You can configure the interval between 400 milliseconds and 10 seconds. You can also configure a timeout value with a range of 3 to 20 seconds; the default timeout value is 5 seconds. The peer-keepalive status is checked only when the peer-link goes down.

The vPC peer-keepalive can be carried either in the management or default VRF on the Cisco Nexus device. When you configure the switches to use the management VRF, the source and destination for the keepalive messages are the mgmt 0 interface IP addresses. When you configure the switches to use the default VRF, an SVI must be created to act as the source and destination addresses for the vPC peer-keepalive messages. Ensure that both the source and destination IP addresses used for the peer-keepalive messages are unique in your network and these IP addresses are reachable from the VRF associated with the vPC peer-keepalive link.

Note

We recommend that you configure the vPC peer-keepalive link on the Cisco Nexus device to run in the management VRF using the mgmt 0 interfaces. If you configure the default VRF, ensure that the vPC peer link is not used to carry the vPC peer-keepalive messages.

Compatibility Parameters for vPC Peer Links

Many configuration and operational parameters must be identical on all interfaces in the vPC. After you enable the vPC feature and configure the peer link on both vPC peer switches, Cisco Fabric Services (CFS) messages provide a copy of the configuration on the local vPC peer switch configuration to the remote vPC peer switch. The system then determines whether any of the crucial configuration parameters differ on the two switches.

Enter the show vpc consistency-parameters command to display the configured values on all interfaces in the vPC. The displayed configurations are only those configurations that would limit the vPC peer link and vPC from coming up.

The compatibility check process for vPCs differs from the compatibility check for regular EtherChannels.

Configuration Parameters That Must Be Identical

The configuration parameters in this section must be configured identically on both switches at either end of the vPC peer link.

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Note

You must ensure that all interfaces in the vPC have the identical operational and configuration parameters listed in this section.

The switch automatically check for compatibility of these parameters on the vPC interfaces. The per-interface parameters must be consistent per interface, and the global parameters must be consistent globally.

• Port-channel mode: on, off, or active

• Link speed per channel

• Duplex mode per channel

• Trunk mode per channel:

◦ Native VLAN

◦ VLANs allowed on trunk

◦ Tagging of native VLAN traffic

• Spanning Tree Protocol (STP) mode

• STP region configuration for Multiple Spanning Tree (MST)

• Enable or disable state per VLAN

• STP global settings:

◦ Bridge Assurance setting

◦ Port type setting—We recommend that you set all vPC interfaces as normal ports

◦ Loop Guard settings

• STP interface settings:

◦ Port type setting

◦ Loop Guard

◦ Root Guard

• For the Fabric Extender vPC topology, all the interface level parameters mentioned above should be identically configured for host interface from both the switches.

• Fabric Extender FEX number configured on an EtherChannel fabric interface; for the Fabric Extender vPC toplogy.

If any of these parameters are not enabled or defined on either switch, the vPC consistency check ignores those parameters.

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Graceful Type-1 Check

Note

To ensure that none of the vPC interfaces are in the suspend mode, enter the show vpc brief and show vpc consistency-parameters commands and check the syslog messages.

Configuration Parameters That Should Be Identical

When any of the following parameters are not configured identically on both vPC peer switches, a misconfiguration may cause undesirable behavior in the traffic flow:

• MAC aging timers

• Static MAC entries

• VLAN interface—Each switch on the end of the vPC peer link must have a VLAN interface configured for the same VLAN on both ends and they must be in the same administrative and operational mode. Those VLANs configured on only one switch of the peer link do not pass traffic using the vPC or peer link. You must create all VLANs on both the primary and secondary vPC switches, or the VLAN will be suspended.

• Private VLAN configuration

• All ACL configurations and parameters

• Quality of service (QoS) configuration and parameters—Local parameters; global parameters must be identical

• STP interface settings:

◦ BPDU Filter

◦ BPDU Guard

◦ Cost

◦ Link type

◦ Priority

◦ VLANs (Rapid PVST+)

To ensure that all the configuration parameters are compatible, we recommend that you display the configurations for each vPC peer switch once you configure the vPC.

Graceful Type-1 Check

Beginning with Cisco NX--OS Release 5.0(2)N2(1), when a consistency check fails, vPCs are brought down only on the secondary vPC switch. The VLANs remain up on the primary switch and Type-1 configurations can be performed without traffic disruption. This feature is used both in the case of global as well as interface-specific Type-1 inconsistencies.

This feature is not enabled for dual-active FEX ports. When a Type-1 mismatch occurs, VLANs are suspended on these ports on both switches.

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Per-VLAN Consistency Check

Beginning with Cisco NX-OS Release 5.0(2)N2(1), some Type-1 consistency checks are performed on a per-VLAN basis when spanning tree is enabled or disabled on a VLAN. VLANs that do not pass the consistency check are brought down on both the primary and secondary switches while other VLANs are not affected.

vPC Auto-Recovery

Beginning with Cisco NX-OS Release 5.0(2)N2(1), the vPC auto-recovery feature re-enables vPC links in the following scenarios:

When both vPC peer switches reload and only one switch reboots, auto-recovery allows that switch to assume the role of the primary switch and the vPC links will be allowed to come up after a predetermined period of time. The reload delay period in this scenario can range from 240-3600 seconds.

When vPCs are disabled on a secondary vPC switch due to a peer-link failure and then the primary vPC switch fails or is unable to forward traffic, the secondary switch re-enables the vPCs. In this scenario, the vPC waits for three consecutive keep-alive failures to recover the vPC links.

The vPC auto-recovery feature is disabled by default.

Configuring Virtual Port Channels

vPC Peer Links

A vPC peer link is the link that is used to synchronize the states between the vPC peer devices.

Note

vPC Peer Link Overview

You must configure the peer-keepalive link before you configure the vPC peer link or the peer link will not come up.

You can have only two switches as vPC peers; each switch can serve as a vPC peer to only one other vPC peer. The vPC peer switches can also have non-vPC links to other switches.

To make a valid configuration, you configure an EtherChannel on each switch and then configure the vPC domain. You assign the EtherChannel on each switch as a peer link. For redundancy, we recommend that you should configure at least two dedicated ports into the EtherChannel; if one of the interfaces in the vPC peer link fails, the switch automatically falls back to use another interface in the peer link.

We recommend that you configure the EtherChannels in trunk mode.Note

Many operational parameters and configuration parameters must be the same in each switch connected by a vPC peer link. Because each switch is completely independent on the management plane, you must ensure that the switches are compatible on the critical parameters. vPC peer switches have separate control planes. After configuring the vPC peer link, you should display the configuration on each vPC peer switch to ensure that the configurations are compatible.

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vPC Number

Note

You must ensure that the two switches connected by the vPC peer link have certain identical operational and configuration parameters.

When you configure the vPC peer link, the vPC peer switches negotiate that one of the connected switches is the primary switch and the other connected switch is the secondary switch. By default, the Cisco NX-OS software uses the lowest MAC address to elect the primary switch. The software takes different actions on each switch—that is, the primary and secondary—only in certain failover conditions. If the primary switch fails, the secondary switch becomes the operational primary switch when the system recovers, and the previously primary switch is now the secondary switch.

You can also configure which of the vPC switches is the primary switch. If you want to configure the role priority again to make one vPC switch the primary switch, configure the role priority on both the primary and secondary vPC switches with the appropriate values, shut down the EtherChannel that is the vPC peer link on both switches by entering the shutdown command, and reenable the EtherChannel on both switches by entering the no shutdown command.

MAC addresses that are learned over vPC links are also synchronized between the peers.

Configuration information flows across the vPC peer links using the Cisco Fabric Services over Ethernet (CFSoE) protocol. All MAC addresses for those VLANs configured on both switches are synchronized between vPC peer switches. The software uses CFSoE for this synchronization.

If the vPC peer link fails, the software checks the status of the remote vPC peer switch using the peer-keepalive link, which is a link between vPC peer switches, to ensure that both switches are up. If the vPC peer switch is up, the secondary vPC switch disables all vPC ports on its switch. The data then forwards down the remaining active links of the EtherChannel.

The software learns of a vPC peer switch failure when the keepalive messages are not returned over the peer-keepalive link.

Use a separate link (vPC peer-keepalive link) to send configurable keepalive messages between the vPC peer switches. The keepalive messages on the vPC peer-keepalive link determines whether a failure is on the vPC peer link only or on the vPC peer switch. The keepalive messages are used only when all the links in the peer link fail.

vPC Number

Once you have created the vPC domain ID and the vPC peer link, you can create EtherChannels to attach the downstream switch to each vPC peer switch. That is, you create one single EtherChannel on the downstream switch with half of the ports to the primary vPC peer switch and the other half of the ports to the secondary peer switch.

On each vPC peer switch, you assign the same vPC number to the EtherChannel that connects to the downstream switch. You will experience minimal traffic disruption when you are creating vPCs. To simplify the configuration, you can assign the vPC ID number for each EtherChannel to be the same as the EtherChannel itself (that is, vPC ID 10 for EtherChannel 10).

Note

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The vPC number that you assign to the EtherChannel connecting to the downstream switch from the vPC peer switch must be identical on both vPC peer switches.

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Configuring vPC Peer Links and Links to the Core

Configure the command line interface by using a track object and a track list that is associated with the Layer 3 link to the core and on all vPC peer links on both vPC peer devices. You use this configuration to avoid dropping traffic if that particular module goes down because when all the tracked objects on the track list go down, the system does the following:

• Stops the vPC primary peer device sending peer-keepalive messages which forces the vPC secondary peer device to take over.

• Brings down all the downstream vPCs on that vPC peer device, which forces all the traffic to be rerouted in the access switch toward the other vPC peer device.

Once you configure this feature and if the module fails, the system automatically suspends all the vPC links on the primary vPC peer device and stops the peer-keepalive messages. This action forces the vPC secondary device to take over the primary role and all the vPC traffic to go to this new vPC primary device until the system stabilizes.

Create a track list that contains all the links to the core and all the vPC peer links as its object. Enable tracking for the specified vPC domain for this track list. Apply this same configuration to the other vPC peer device.

Configuring Virtual Port Channels

Before You Begin

To configure a track list to switch over vPC to the remote peer when all related interfaces fail:

Procedure

PurposeCommand or Action

Step 1

Step 2

Step 3

Step 4

Step 5

Step 6

switch(config)# interface type slot/port

switch(config-if)# track track-id interface type slot/port line-protocol

switch(config-track)# track track-id interface type slot/port line-protocol

switch(config)# track track-id interface

port-channel port line-protocol

switch(config)# track track-id list boolean [OR | AND]

Enters global configuration mode.switch# configure terminal

Enters interface configuration mode.

Configures the track objects on an interface (Layer 3 to core).

Tracks the objects on an interface (Layer 3 to core).

Configures the track objects on a port channel (vPC peer link).

Creates a track list that contains all the interfaces in the track list using the Boolean OR to trigger when all the objects fail. or trigger a switchover when any core interface or peer-link goes down using Boolean AND.

Step 7

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switch(config-track)# object number

Specifiecs the object number.

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PurposeCommand or Action

Step 8

Step 9

Step 10

Step 11

switch(config)# vpc domain domain-id

switch(config-vpc-domain)# track number

switch(config)# show vpc brief

Exits track configuration mode.switch(config-track)# end

Enters vPC domain configuration.

Adds the track object to the vPC domain.

(Optional) Displays the track object.

Step 12

switch(config)# copy running-config startup-config

(Optional) Saves the change persistently through reboots and restarts by copying the running configuration to the startup configuration.

This example shows how to configure a track list to trigger when all the objects fail using Boolean OR:

switch# configure terminal switch(config)# interface ethernet 8/35 switch(config-if)# track 35 interface ethernet 8/35 line-protocol switch(config-track)# track 23 interface ethernet 8/33 line-protocol switch(config)# track 55 interface port-channel 100 line-protocol switch(config)# track 44 list boolean OR switch(config-track)# object 23 switch(config-track)# object 35 switch(config-track)# object 55 switch(config-track)# end switch(config)# vpc domain 1 switch(config-vpc-domain)# track 44 switch(config)# copy running-config startup-config

vPC and LACP

The Link Aggregation Control Protocol (LACP) uses the system MAC address of the vPC domain to form the LACP Aggregation Group (LAG) ID for the vPC.

You can use LACP on all the vPC EtherChannels, including those channels from the downstream switch. We recommend that you configure LACP with active mode on the interfaces on each EtherChannel on the vPC peer switches. This configuration allows you to more easily detect compatibility between switches, unidirectional links, and multihop connections, and provides dynamic reaction to run-time changes and link failures.

The vPC peer link supports 16 EtherChannel interfaces.

Note

When manually configuring the system priority, you must ensure that you assign the same priority value on both vPC peer switches. If the vPC peer switches have different system priority values, vPC will not come up.

vPC Peer Links and STP

When you first bring up the vPC functionality, STP reconverges. STP treats the vPC peer link as a special link and always includes the vPC peer link in the STP active topology.

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We recommend that you set all the vPC peer link interfaces to the STP network port type so that Bridge Assurance is automatically enabled on all vPC peer links. We also recommend that you do not enable any of the STP enhancement features on VPC peer links.

You must configure a list of parameters to be identical on the vPC peer switches on both sides of the vPC peer link.

STP is distributed; that is, the protocol continues running on both vPC peer switches. However, the configuration on the vPC peer switch elected as the primary switch controls the STP process for the vPC interfaces on the secondary vPC peer switch.

The primary vPC switch synchronizes the STP state on the vPC secondary peer switch using Cisco Fabric Services over Ethernet (CFSoE).

The vPC manager performs a proposal/handshake agreement between the vPC peer switches that sets the primary and secondary switches and coordinates the two switches for STP. The primary vPC peer switch then controls the STP protocol for vPC interfaces on both the primary and secondary switches.

The Bridge Protocol Data Units (BPDUs) use the MAC address set for the vPC for the STP bridge ID in the designated bridge ID field. The vPC primary switch sends these BPDUs on the vPC interfaces.

Configuring Virtual Port Channels

Note

vPC and ARP

CFSoE

Display the configuration on both sides of the vPC peer link to ensure that the settings are identical. Use the show spanning-tree command to display information about the vPC.

Table synchronization across vPC peers is managed in Cisco NX-OS using the reliable transport mechanism of the Cisco Fabric Services over Ethernet (CFSoE) protocol. To support faster convergence of address tables between the vPC peers, the ip arp synchronize command must be enabled. This convergence is designed to overcome the delay involved in ARP table restoration when the peer-link port channel flaps or when a vPC peer comes back online.

To improve performance, we recommend that you turn on the ARP sync feature. By default, it is not enabled.

To check whether or not ARP sync is enabled, enter the following command:

switch# show running

To enable ARP sync, enter the following command:

switch(config-vpc-domain) # ip arp synchronize

The Cisco Fabric Services over Ethernet (CFSoE) is a reliable state transport mechanism that you can use to synchronize the actions of the vPC peer devices. CFSoE carries messages and packets for many features linked with vPC, such as STP and IGMP. Information is carried in CFS/CFSoE protocol data units (PDUs).

When you enable the vPC feature, the device automatically enables CFSoE, and you do not have to configure anything. CFSoE distributions for vPCs do not need the capabilities to distribute over IP or the CFS regions. You do not need to configure anything for the CFSoE feature to work correctly on vPCs.

You can use the show mac address-table command to display the MAC addresses that CFSoE synchronizes for the vPC peer link.

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vPC Peer Switch

Note

Do not enter the no cfs eth distribute or the no cfs distribute command. CFSoE must be enabled for vPC functionality. If you do enter either of these commands when vPC is enabled, the system displays an error message.

When you enter the show cfs application command, the output displays "Physical-eth," which shows the applications that are using CFSoE.

vPC Peer Switch

The vPC peer switch feature addresses performance concerns around STP convergence. This feature allows a pair of Cisco Nexus devices to appear as a single STP root in the Layer 2 topology. This feature eliminates the need to pin the STP root to the vPC primary switch and improves vPC convergence if the vPC primary switch fails.

To avoid loops, the vPC peer link is excluded from the STP computation. In vPC peer switch mode, STP BPDUs are sent from both vPC peer devices to avoid issues related to STP BPDU timeout on the downstream switches, which can cause traffic disruption.

This feature can be used with the pure peer switch topology in which the devices all belong to the vPC.

Note

Peer-switch feature is supported on networks that use vPC and STP-based redundancy is not supported. If the vPC peer-link fail in a hybrid peer-switch configuration, you can lose traffic. In this scenario, the vPC peers use the same STP root ID as well same bridge ID. The access switch traffic is split in two with half going to the first vPC peer and the other half to the second vPC peer. With the peer link failed, there is no impact on north/south traffic but east-west traffic will be lost (black-holed).

For information on STP enhancement features and Rapid PVST+, see the Layer 2 Switching Configuration Guide for your device.

Guidelines and Limitations for vPCs

vPC has the following configuration guidelines and limitations:

• You must enable the vPC feature before you can configure vPC peer-link and vPC interfaces.

• You must configure the peer-keepalive link before the system can form the vPC peer link.

• The vPC peer-link needs to be formed using a minimum of two 10-Gigabit Ethernet interfaces.

• You can connect a pair of Cisco Nexus 5000 Series switches or a pair of Cisco Nexus 5500 Series switches in a vPC directly to another switch or to a server. vPC peer switches must be of the same type, for example, you can connect a pair of Nexus 5000 series switches or a pair of Nexus 5500 Series switches but you cannot connect a Nexus 5000 Series switch to a Nexus 5500 Series switch in a vPC topology.

• Only port channels can be in vPCs. A vPC can be configured on a normal port channel (switch-to-switch vPC topology), on a port channel fabric interface (fabric extender vPC topology), and on a port channel host interface (host interface vPC topology).

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Configuring vPCs

Configuring Virtual Port Channels

• A Fabric Extender can be a member of a Host Interface vPC topology or a Fabric Extender vPC topology but not both simultaneously.

• You must configure both vPC peer switches; the configuration is not automatically synchronized between the vPC peer devices.

• Check that the necessary configuration parameters are compatible on both sides of the vPC peer link.

• You may experience minimal traffic disruption while configuring vPCs.

• You should configure all the port channels in the vPC using LACP with the interfaces in active mode.

• When the peer-switch command is configured and vPC keepalive messages exchanged through an SVI instead of a management interface, additional Spanning Tree Protocol (STP) configuration is required. STP needs to be disabled on the dedicated link that carries the keepalive traffic between the vPC peers. You can disable STP on the dedicated link by configuring STP BPDUfilter on the both ends of the dedicated link. We recommend that the VLAN of the vPC keepalive SVI be allowed on only the interconnecting dedicated link and disallowed on all other links, including the peer link.

Configuring vPCs

Enabling vPCs

You must enable the vPC feature before you can configure and use vPCs.

Procedure

Step 1

Step 2

Step 3

Step 4

This example shows how to enable the vPC feature:

switch# configure terminal switch(config)# feature vpc

switch# show feature

switch# copy running-config

startup-config

PurposeCommand or Action

Enters configuration mode.switch# configure terminal

Enables vPCs on the switch.switch(config)# feature vpc

(Optional) Displays which features are enabled on the switch.

(Optional) Copies the running configuration to the startup configuration.

Disabling vPCs

You can disable the vPC feature.

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Configuring Virtual Port Channels

When you disable the vPC feature, the Cisco Nexus device clears all the vPC configurations.Note

Procedure

Creating a vPC Domain

PurposeCommand or Action

Step 1

Step 2

Step 3

Step 4

This example shows how to disable the vPC feature:

switch# configure terminal switch(config)# no feature vpc

Creating a vPC Domain

You must create identical vPC domain IDs on both the vPC peer devices. This domain ID is used to automatically form the vPC system MAC address.

Before You Begin

Ensure that you have enabled the vPC feature.

You must configure both switches on either side of the vPC peer link with the following procedure.

switch# show feature

switch# copy running-config

startup-config

Enters configuration mode.switch# configure terminal

Disables vPCs on the switch.switch(config)# no feature vpc

(Optional) Displays which features are enabled on the switch.

(Optional) Copies the running configuration to the startup configuration.

Procedure

PurposeCommand or Action

Step 1

Step 2

switch(config)# vpc domain

domain-id

Enters configuration mode.switch# configure terminal

Creates a vPC domain on the switch, and enters the vpc-domain configuration mode. There is no default domain-id ; the range is from 1 to 1000.

Note

You can also use the vpc domain command to enter the vpc-domain configuration mode for an existing vPC domain.

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Configuring a vPC Keepalive Link and Messages

Configuring Virtual Port Channels

PurposeCommand or Action

Step 3

switch# show vpc brief

(Optional) Displays brief information about each vPC domain.

Step 4

switch# copy running-config startup-config

(Optional) Copies the running configuration to the startup configuration.

This example shows how to create a vPC domain:

switch# configure terminal switch(config)# vpc domain 5

Configuring a vPC Keepalive Link and Messages

You can configure the destination IP for the peer-keepalive link that carries the keepalive messages. Optionally, you can configure other parameters for the keepalive messages.

The Cisco Nexus 5500 Platform switches support VRF lite with Layer 3 modules and with the Base or LAN-Enterprise license installed. This capability allows you to create a VRF and assign a specific interface to the VRF. Prior to this release, two VRFs are created by default: VRF management and VRF default. The mgmt0 interface and all SVI interfaces reside in VRF management and default.

The Cisco NX-OS software uses the peer-keepalive link between the vPC peers to transmit periodic, configurable keepalive messages. You must have Layer 3 connectivity between the peer devices to transmit these messages. The system cannot bring up the vPC peer link unless the peer-keepalive link is already up and running.

Ensure that both the source and destination IP addresses used for the peer-keepalive message are unique in your network and these IP addresses are reachable from the Virtual Routing and Forwarding (VRF) associated with the vPC peer-keepalive link.

Note

We recommend that you configure a separate VRF instance and put a Layer 3 port from each vPC peer switch into that VRF for the vPC peer-keepalive link. Do not use the peer link itself to send vPC peer-keepalive messages. For information on creating and configuring VRFs, see the Unicast Routing Configuration Guide for your device.

Before You Begin

Ensure that you have enabled the vPC feature.

You must configure the vPC peer-keepalive link before the system can form the vPC peer link.

You must configure both switches on either side of the vPC peer link with the following procedure.

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Procedure

Configuring a vPC Keepalive Link and Messages

PurposeCommand or Action

Step 1

Step 2

Step 3

Step 4

Step 5

switch(config)# vpc domain domain-id

switch(config-vpc-domain)# peer-keepalive

destination ipaddress [hold-timeout secs | interval msecs {timeout secs} | precedence {prec-value | network | internet | critical | flash-override | flash | immediate priority | routine} | tos {tos-value | max-reliability | max-throughput | min-delay | min-monetary-cost | normal} | tos-byte

tos-byte-value} | source ipaddress | vrf {name | management vpc-keepalive}]

switch(config-vpc-domain)# vpc

peer-keepalive destination ipaddress source ipaddress

switch# show vpc peer-keepalive

Enters configuration mode.switch# configure terminal

Creates a vPC domain on the switch if it does not already exist, and enters the vpc-domain configuration mode.

Configures the IPv4 address for the remote end of the vPC peer-keepalive link.

Note

The system does not form the vPC peer link until you configure a vPC peer-keepalive link.

The management ports and VRF are the defaults

(Optional) Configures a separate VRF instance and puts a Layer 3 port from each vPC peer device into that VRF for the vPC peer-keepalive link.

(Optional) Displays information about the configuration for the keepalive messages.

Step 6

switch# copy running-config startup-config

(Optional) Copies the running configuration to the startup configuration.

This example shows how to configure the destination IP address for the vPC-peer-keepalive link:

switch# configure terminal switch(config)# vpc domain 5 switch(config-vpc-domain)# peer-keepalive destination 10.10.10.42

This example shows how to set up the peer keepalive link connection between the primary and secondary vPC device:

switch(config)# vpc domain 100 switch(config-vpc-domain)# peer-keepalive destination 192.168.2.2 source 192.168.2.1 Note:--------:: Management VRF will be used as the default VRF ::-------switch(config-vpc-domain)#

This example shows how to create a separate VRF named vpc_keepalive for the vPC keepalive link and how to verify the new VRF:

vrf context vpc_keepalive

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Creating a vPC Peer Link

interface Ethernet1/31

interface Vlan123

vpc domain 1

vpc_keepalive

L3-NEXUS-2# sh vpc peer-keepalive

vPC keep-alive status : peer is alive

--Peer is alive for : (154477) seconds, (908) msec

--Send status : Success

--Last send at : 2011.01.14 19:02:50 100 ms

--Sent on interface : Vlan123

--Receive status : Success

--Last receive at : 2011.01.14 19:02:50 103 ms

--Received on interface : Vlan123

--Last update from peer : (0) seconds, (524) msec

vPC Keep-alive parameters

--Destination : 123.1.1.1

--Keepalive interval : 1000 msec

--Keepalive timeout : 5 seconds

--Keepalive hold timeout : 3 seconds

--Keepalive vrf : vpc_keepalive

--Keepalive udp port : 3200

--Keepalive tos : 192

The services provided by the switch , such as ping, ssh, telnet, radius, are VRF aware. The VRF name need to be configured or specified in order for the correct routing table to be used. L3-NEXUS-2# ping 123.1.1.1 vrf vpc_keepalive PING 123.1.1.1 (123.1.1.1): 56 data bytes 64 bytes from 123.1.1.1: icmp_seq=0 ttl=254 time=3.234 ms 64 bytes from 123.1.1.1: icmp_seq=1 ttl=254 time=4.931 ms 64 bytes from 123.1.1.1: icmp_seq=2 ttl=254 time=4.965 ms 64 bytes from 123.1.1.1: icmp_seq=3 ttl=254 time=4.971 ms 64 bytes from 123.1.1.1: icmp_seq=4 ttl=254 time=4.915 ms

--- 123.1.1.1 ping statistics --5 packets transmitted, 5 packets received, 0.00% packet loss round-trip min/avg/max = 3.234/4.603/4.971 ms

Configuring Virtual Port Channels

switchport access vlan 123

vrf member vpc_keepalive ip address 123.1.1.2/30 no shutdown

peer-keepalive destination 123.1.1.1 source 123.1.1.2 vrf

Creating a vPC Peer Link

You can create a vPC peer link by designating the EtherChannel that you want on each switch as the peer link for the specified vPC domain. We recommend that you configure the EtherChannels that you are designating as the vPC peer link in trunk mode and that you use two ports on separate modules on each vPC peer switch for redundancy.

Before You Begin

Ensure that you have enabled the vPC feature.

You must configure both switches on either side of the vPC peer link with the following procedures

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Procedure

Creating a vPC Peer Link

PurposeCommand or Action

Step 1

Step 2

switch(config)# interface port-channel channel-number

Step 3

Step 4

Step 5

switch(config-if)# vpc peer-link

switch# show vpc brief

switch# copy running-config

startup-config

This example shows how to configure a vPC peer link:

switch# configure terminal switch(config)# interface port-channel 20 switch(config-if)# vpc peer-link

Checking the Configuration Compatibility

Enters configuration mode.switch# configure terminal

Selects the EtherChannel that you want to use as the vPC peer link for this switch, and enters the interface configuration mode.

Configures the selected EtherChannel as the vPC peer link, and enters the vpc-domain configuration mode.

(Optional) Displays information about each vPC, including information about the vPC peer link.

(Optional) Copies the running configuration to the startup configuration.

Note

After you have configured the vPC peer link on both vPC peer switches, check that the configurations are consistent on all vPC interfaces.

Beginning with Cisco NX-OS Release 5.0(2)N1(1), the following QoS parameters support Type 2 consistency checks:

• Network QoS—MTU and Pause

• Input Queuing —Bandwidth and Absolute Priority

• Output Queuing—Bandwidth and Absolute Priority

In the case of a Type 2 mismatch, the vPC is not suspended. Type 1 mismatches suspend the vPC.

Default SettingParameter

switch# show vpc consistency-parameters {global | interface port-channel channel-number}

Displays the status of those parameters that must be consistent across all vPC interfaces.

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Enabling vPC Auto-Recovery

This example shows how to check that the required configurations are compatible across all the vPC interfaces:

switch# show vpc consistency-parameters global

Name Type Local Value Peer Value

------------- ---- ---------------------- ----------------------QoS 2 ([], [], [], [], [], ([], [], [], [], [],

Network QoS (MTU) 2 (1538, 0, 0, 0, 0, 0) (1538, 0, 0, 0, 0, 0) Network Qos (Pause) 2 (F, F, F, F, F, F) (1538, 0, 0, 0, 0, 0) Input Queuing (Bandwidth) 2 (100, 0, 0, 0, 0, 0) (100, 0, 0, 0, 0, 0) Input Queuing (Absolute 2 (F, F, F, F, F, F) (100, 0, 0, 0, 0, 0) Priority) Output Queuing (Bandwidth) 2 (100, 0, 0, 0, 0, 0) (100, 0, 0, 0, 0, 0) Output Queuing (Absolute 2 (F, F, F, F, F, F) (100, 0, 0, 0, 0, 0) Priority) STP Mode 1 Rapid-PVST Rapid-PVST STP Disabled 1 None None STP MST Region Name 1 "" "" STP MST Region Revision 1 0 0 STP MST Region Instance to 1

VLAN Mapping

STP Loopguard 1 Disabled Disabled STP Bridge Assurance 1 Enabled Enabled STP Port Type, Edge 1 Normal, Disabled, Normal, Disabled, BPDUFilter, Edge BPDUGuard Disabled Disabled STP MST Simulate PVST 1 Enabled Enabled Allowed VLANs - 1,624 1 Local suspended VLANs - 624 switch#

This example shows how to check that the required configurations are compatible for an EtherChannel interface:

switch# show vpc consistency-parameters interface port-channel 20

Configuring Virtual Port Channels

Legend:

Type 1 : vPC will be suspended in case of mismatch

[]) [])

Legend:

Name Type Local Value Peer Value

------------- ---- ---------------------- ----------------------Fex id 1 20 20 STP Port Type 1 Default Default STP Port Guard 1 None None STP MST Simulate PVST 1 Default Default mode 1 on on Speed 1 10 Gb/s 10 Gb/s Duplex 1 full full Port Mode 1 fex-fabric fex-fabric Shut Lan 1 No No Allowed VLANs - 1,3-3967,4048-4093 1-3967,4048-4093

Type 1 : vPC will be suspended in case of mismatch

Enabling vPC Auto-Recovery

Procedure

Step 1

Step 2

switch(config)# vpc domain domain-id

PurposeCommand or Action

Enters configuration mode.switch# configure terminal

Enters vpc-domain configuration mode for an existing vPC domain.

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Configuring Virtual Port Channels

Suspending Orphan Ports on a Secondary Switch in a vPC Topology

PurposeCommand or Action

Step 3

switch(config-vpc-domain)# auto-recovery reload-delay delay

Enables the auto-recovery feature and sets the reload delay period. The default is disabled.

This example shows how to enable the auto-recovery feature in vPC domain 10 and set the delay period for 240 seconds.

switch(config)# vpc domain 10 switch(config-vpc-domain)# auto-recovery reload-delay 240 Warning:

Enables restoring of vPCs in a peer-detached state after reload, will wait for 240 seconds (by default) to determine if peer is un-reachable

This example shows how to view the status of the auto-recovery feature in vPC domain 10:

switch(config-vpc-domain)# show running-config vpc !Command: show running-config vpc !Time: Tue Dec 7 02:38:44 2010

version 5.0(2)N2(1)

feature vpc vpc domain 10

peer-keepalive destination 10.193.51.170

auto-recovery

Suspending Orphan Ports on a Secondary Switch in a vPC Topology

Note

You can suspend a non-virtual port channel (vPC) port when a vPC secondary peer link goes down. A non-vPC port, also known as an orphaned port, is a port that is not part of a vPC.

When a port is configured as an orphan port, the port will flap. This occurs because the system reevaluates whether the port can be brought up, given the constraints of the orphan port. For example, MCT needs to be up and election needs to be complete.

Before You Begin

Enable the vPC feature.

Procedure

PurposeCommand or Action

Step 1

Step 2

Step 3

switch(config)# interface ethernet slot/port

switch(config-if)# vpc orphan-port

suspend

Enters configuration mode.switch# configure terminal

Specifies the port that you want to configure and enters interface configuration mode.

Suspends the specified port if the secondary switch goes down.

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Creating an EtherChannel Host Interface

PurposeCommand or Action

Note

Configuring Virtual Port Channels

The vpc-orphan-port suspend command is supported only on physical ports.

Step 4

Step 5

switch# show vpc orphan-port

Exits interface configuration mode.switch(config-if)# exit

(Optional) Displays the orphan port configuration.

Step 6

switch# copy running-config startup-config

(Optional) Copies the running configuration to the startup configuration.

This example shows how to suspend an orphan port:

switch# configure terminal switch(config)# interface ethernet ½0 switch(config-if)# vpc orphan-port suspend

This example shows how to display ports that are not part of the vPC but that share common VLANs with ports that are part of the vPC:

switch# configure terminal switch(config)# show vpc orphan-ports Note:

--------::Going through port database. Please be patient.::-------VLAN Orphan Ports

------- ------------------------1 Po600 2 Po600 3 Po600 4 Po600 5 Po600 6 Po600 7 Po600 8 Po600 9 Po600 10 Po600 11 Po600 12 Po600 13 Po600 14 Po600 ...

Creating an EtherChannel Host Interface

To connect to a downstream server from a Cisco Nexus 2000 Series Fabric Extender you can create a EtherChannel host interface. An EtherChannel host interface can have only one host interface as a member depending on the fabric extender model. The Cisco Nexus 2148T allows only one interface member per fabric extender, newer fabric extenders allow up to 8 members of the same port-channel on a single fabric extender. You need to create an EtherChannel host interface to configure a vPC on it that uses the Fabric Extender topology.

Before You Begin

Ensure that you have enabled the vPC feature.

Ensure that the connected Fabric Extender is online.

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Cisco Systems Nexus 5596t User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

Cisco Nexus 5000 Series NX-OS Interfaces Configuration Guide, Release 5.2(1)N1(1)

CONTENTS

Preface

Audience

Document Conventions

Documentation Feedback

Obtaining Documentation and Submitting a Service Request

New and Changed Information for this Release

New and Changed Information for this Release

Configuring Layer 2 Interfaces

Information About Ethernet Interfaces

About the Interface Command

Information About Unified Ports

Guidelines and Limitations for Unified Ports

About the Unidirectional Link Detection Parameter

Default UDLD Configuration

Interface Speed

UDLD Aggressive and Nonaggressive Modes

About the Cisco Discovery Protocol

Default CDP Configuration

About the Error-Disabled State

About Port Profiles

Guidelines and Limitations for Port Profiles

About the Debounce Timer Parameters

About MTU Configuration

Configuring Ethernet Interfaces

Configuring a Layer 3 Interface on a Cisco Nexus 5500 Platform Switch

Configuring Unified Ports

Configuring the UDLD Mode

Configuring Interface Speed

Disabling Link Negotiation

Configuring the CDP Characteristics

Enabling or Disabling CDP

Enabling the Error-Disabled Detection

Enabling the Error-Disabled Recovery

Configuring the Error-Disabled Recovery Interval

Port Profiles

Creating a Port Profile

Modifying a Port Profile

Enabling a Specific Port Profile

Inheriting a Port Profile

Removing an Inherited Port Profile

Assigning a Port Profile to a Range of Interfaces

Removing a Port Profile from a Range of Interfaces

Configuration Examples for Port Profiles

Configuring the Debounce Timer

Configuring the Description Parameter

Disabling and Restarting Ethernet Interfaces

Displaying Interface Information

Default Physical Ethernet Settings

Configuring Layer 3 Interfaces

Information About Layer 3 Interfaces

Routed Interfaces

Subinterfaces

VLAN Interfaces

Loopback Interfaces

Tunnel Interfaces

Licensing Requirements for Layer 3 Interfaces

Configuring Layer 3 Interfaces

Guidelines and Limitations for Layer 3 Interfaces

Default Settings for Layer 3 Interfaces

Configuring a Routed Interface

Configuring a Subinterface

Configuring the Bandwidth on an Interface

Configuring a VLAN Interface

Configuring a Loopback Interface

Assigning an Interface to a VRF

Verifying the Layer 3 Interfaces Configuration

Monitoring Layer 3 Interfaces

Configuration Examples for Layer 3 Interfaces

Related Documents for Layer 3 Interfaces

MIBs for Layer 3 Interfaces

Standards for Layer 3 Interfaces

Configuring Port Channels

Information About Port Channels

Understanding Port Channels