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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CONTENTS
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
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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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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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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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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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
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
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.
Table 1: New Features
Where DocumentedDescriptionFeature
Added support for IPv6 addressing.IPv6
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• Routed Interfaces, on page
33
• 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
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
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
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.
Note
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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
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
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
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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