Dell N3024, N2048 User Manual

Using MLAG in Dell Networks

A deployment guide for Dell Networking switches

Victor Teeter
Dell Engineering
January 2014

January 2014

A Dell Deployment and Configuration Guide

Revisions

Date

Description

January, 2014

Initial Release

PAPER IS FOR INFORMATIONAL PURPOSES ONLY, AND MAY CONTAIN TYPOGRAPHICAL ERRORS AND TECHNICAL
INACCURACIES. THE CONTENT IS PROVIDED AS IS, WITHOUT EXPRESS OR IMPLIED WARRANTIES OF ANY KIND.

© 2014 Dell Inc. All rights reserved. Reproduction of this material in any manner whatsoever without the express written permission
of Dell Inc. is strictly forbidden. For more information, contact Dell.
PRODUCT WARRANTIES APPLICABLE TO THE DELL PRODUCTS DESCRIBED IN THIS DOCUMENT MAY BE FOUND AT:

http://www.dell.com/learn/us/en/19/terms-of-sale-commercial-and-public-sector Performance of network reference

architectures discussed in this document may vary with differing deployment conditions, network loads, and the like. Third party
products may be included in reference architectures for the convenience of the reader. Inclusion of such third party products does
not necessarily constitute Dell’s recommendation of those products. Please consult your Dell representative for additional
information.
Trademarks used in this text: Dell™, the Dell logo, PowerConnect™, OpenManage™, EqualLogic™, Compellent™, and Force10™
are trademarks of Dell Inc. Other Dell trademarks may be used in this document. Cisco Nexus®, Cisco MDS®, Cisco NX-0S®, and
other Cisco Catalyst® are registered trademarks of Cisco System Inc. Microsoft®, Windows®, Windows Server®, Internet Explorer®,
MS-DOS®, Windows Vista® and Active Directory® are either trademarks or registered trademarks of Microsoft Corporation in the
United States and/or other countries. Broadcom® and NetXtreme® are registered trademarks of Broadcom Corporation. Qlogic is a
registered trademark of QLogic Corporation. Other trademarks and trade names may be used in this document to refer to either
the entities claiming the marks and/or names or their products and are the property of their respective owners. Dell disclaims
proprietary interest in the marks and names of others.

2 Using MLAG in Dell Networks

.

Table of Contents

Revisions ............................................................................................................................................................................................. 2

Executive Summary .......................................................................................................................................................................... 4

1 Introduction ................................................................................................................................................................................ 5

2 Caveats for Enabling MLAG ..................................................................................................................................................... 6

3 Supported Topologies .............................................................................................................................................................. 8

4 Single-Tier Example .................................................................................................................................................................. 9

5 Two-Tier Example ................................................................................................................................................................... 13

6 Using MLAG with VLT or Cisco vPC ..................................................................................................................................... 19

A Additional Resources............................................................................................................................................................... 21

B Configuration details ............................................................................................................................................................... 22

3 Using MLAG in Dell Networks

.

Executive Summary

Multi-switch Link Aggregation or MLAG is a feature that allows two Dell Networking switches to act as a
single switch, provides multiple paths across the network with benefits like:

 Failover in cases of failed cables or switches
 Increased bandwidth of up to double the bandwidth of a single switch
 Elimination of port blocking as well as reconvergence delays of spanning tree

MLAGs are created by connecting a Dell Networking switch to another Dell Networking switch through
Peer-Link ports to create MLAG peers (the two connected switches). Other switches directly connected to
the MLAG peers are unaware that they are connecting to two switches. Two switches appear as a single
switch on the network.

All links in the MLAG can carry data traffic across many physically diverse topologies. In the case of a link
or switch failure, traffic continues to flow with minimal disruption. MLAG optimnizes availability and
bandwidth between attached devices in Dell’s Datacenter and Campus networking solutions.

The following Dell Networking N-series switches support MLAG and may be used in building the
configurations in this white paper:

N2024 N3024 N4032

N2024P N3024P N4032F

N2048 N3024F N4064

N2048P N3048 N4064F

N3048P

4 Using MLAG in Dell Networks

.

MLAG

Secondary MLAG peer

Peer-Link

MLAG

Secondary MLAG peer

Peer-Link

MLAG

Primary MLAG peer

Primary MLAG peer

Partner Switch

Partner Switch Partner Switch

MLAG peers appear

as a single logical

switch to partner

switches on the

network

Simple L2 MLAG

L3 MLAG with mulitple

partner switches

1 Introduction

MLAGs provide an active-active split aggregation deployment across two switches acting as one. MLAG
creates a more resilient network with higher bandwidth capabilities. This white paper discusses MLAGs,
how and when they are used, caveats to look out for, and instructions on how to implement MLAG into
your network.

Figure 1 below shows two very basic examples of MLAG domains. In both examples, peer switches are
linked together with a special LAG (one or more cables as denoted by the red line in the pictures below),
called a Peer-Link. With the Peer-Link configured, the two switches appear as a single switch to partner
switches upstream and downstream. Each partner switch contains MLAGs that are simply LAGs (ling
aggregation groups) whose cables are split between the two peers. Primary and secondary peer roles are
chosen automatically by the program when MLAG is enabled.

5 Using MLAG in Dell Networks

Two examples of a single-tier MLAG topology Figure 1

.

MLAG peer

peer

link

MLAG peer

Link Aggregation

MLAG Port-channels

Interfaces

VLANs

Firmware

Spanning Tree

Link Aggregation

MLAG Port-channels

Interfaces

VLANs

Firmware

Spanning Tree

=
=
=
=
=

=

2 Caveats for Enabling MLAG

There are a few limitations in implementing MLAGs:

 Two identical switch models are required to create MLAG peers. This means an N2048 can only be

peered with another N2048, an N3024 with another N3024, and so on.

 Peer devices must use the same expansion module type if ports from the expansion module are to

be part of the MLAG interface.

 Neither of the two switches used as MLAG peers may be stacked with other switches.
 MLAG status using the show vpc brief command is only run from the primary MLAG peer

when both the primary and secondary peer information is required.

See the switch User Guide for additional information.

Note: Run the show vpc brief command only from the Primary MLAG peer. This provides
information on both peer switches.

2.1 Consistency of MLAG Peers

As mentioned in the section above, the two switches to be used as MLAG peers must be identical models,
as well as any expansion module that is used in the MLAG peer-link setup. There are also six areas in the
software configuration that must be given special attention to ensure they contain identical information

prior to enabling the MLAG. These areas are reflected in Figure 2.

Figure 2

Consistent MLAG peer configurations

6 Using MLAG in Dell Networks

.

Option category

Settings that need to match on both MLAG peers

Link Aggregation

Hashing mode
Minimum links
Static/dynamic LAG
LACP parameters

o Actor parameters
o Admin key
o Collector max-delay
o Partner parameters

Spanning Tree

Bpdufilter
Bpduflood
Auto-edge
TCN-guard
Cost
Edgeport
Root guard
Loop guard
STP Version
STP MST VLAN configuration

port priority, port cost/mode)

MLAG Port-channels

Port-channel mode
Link speed
Duplex mode
MTU
Bandwidth
VLAN configuration

Interfaces

PFC configuration
CoS queue assignments

VLANs

MLAG VLANs must be configured on both
MLAG peers, and connect to two partner LAGs.

Firmware

Both peers require the same firmware version
to operate correctly.

Misc.

FDB entry aging timers
Static MAC entries
ACL configuration

Change any settings mentioned below on both the MLAG peers when required. Enable MLAG only after
the above settings are configured on the two peer switches.

It is also recommended for MLAG to be temporarily disabled in order to make subsequent changes to the
above settings.

Note: Be sure to schedule down time if making changes that impact traffic or cause data loss.

Note: Failure to make these areas identical may cause sporadic traffic issues on the network which are

difficult to troubleshoot.

7 Using MLAG in Dell Networks

.

Table 1 Specific configuration options to be equal among MLAG peers

Topological parameter

Supported options

# of peer switches per MLAG

2

# of layers

1 or 2

# of partner switches

1 to 8 per MLAG

# of peer-links between peers

1 to 8 active per MLAG (up to 8 more inactive)

QSFP+

MASTER

SYS

FAN

PSU

RS-232

ETHERNET

LNK ACT

4644424038363432302826242220181614121086420 48 56

52 60

SFP+

Force10 S4810P

QSFP+

MASTER

SYS

FAN

PSU

RS-232

ETHERNET

LNK ACT

4644424038363432302826242220181614121086420 48 56

52 60

SFP+

Force10 S4810P

2 tier

(2 layer, full mesh)

2 layer (MLAG and VLT)

1 partner switch

3 partner switches

VLTi

2 partner switches

VLTi

3 Supported Topologies

MLAGs topologies contain several options. They can be a single layer (only one pair of MLAG peer
switches) or two layers (two pair of MLAG peer switches).

Each MLAG domain can have anywhere from 1 to 8 partner switches. The peer-link between peers can
have anywhere from 1 to 8 active interfaces to create the link. Given these variables, there are dozens of
ways to setup an MLAG. Table 2 lists all supported topology options.

Table 2 Optional parameters for an MLAG topology

Figure 3 shows just a few examples of MLAG topologies that can be built using the MLAG feature. The red
lines show the peer-lnks between the primary and secondary peer switches.

Examples of MLAG topologies Figure 3

8 Using MLAG in Dell Networks

.

MLAG

MLAG

Secondary MLAG peer

Peer-Link

Primary MLAG peer

Partner Switch B

Partner Switch A

N3048

N3048

(47)

(48)

(11)

(12)

(1/0/1)

(1/0/1)

(30)

(29)

(28)

(27)

Primary MLAG Peer (N3048)

Secondary MLAG Peer N3048)

Description of commands

configure
vlan 30
exit

interface port-channel 1
description "MLAG-Peer-Link"
spanning-tree disable
switchport mode trunk
vpc peer-link
exit

interface tengigabitethernet 1/0/1
channel-group 1 mode active
description "MLAG-Peer-Link"
exit

interface port-channel 30
switchport mode trunk

configure
vlan 30
exit

interface port-channel 1
description "MLAG-Peer-Link"
spanning-tree disable
switchport mode trunk
vpc peer-link
exit

interface tengigabitethernet 1/0/1
channel-group 1 mode active
description "MLAG-Peer-Link"
exit

interface port-channel 30
switchport mode trunk

 Create a VLAN for MLAG and all
partner traffic

 Configure the port channel for
the peer link

- must be trunk mode

 Identify and configure the peer
link interface

 Create a LAG for partner switch
A to pass traffic

4 Single-Tier Example

This example shows the configuration of the two MLAG peers with two MLAG partners. The default
spanning tree configuration is used and spanning tree is disabled on the peer link.

To configure the two MLAG peers in the basic configuration, follow the steps below:

9 Using MLAG in Dell Networks

.

Single tier MLAG topology Figure 4

1. Enter the following commands on both peer switches before enabling MLAG (using

the feature vpc command) on each one. Each column below contains commands
that can be cut and pasted into a CLI session.

Primary MLAG Peer (N3048)

Secondary MLAG Peer N3048)

Description of commands

switchport trunk native vlan 30
vpc 30
exit

interface port-channel 40
switchport mode trunk
switchport trunk native vlan 30
vpc 40
exit

interface gigabitethernet 1/0/47
channel-group 30 mode active
description "MLAG-Partner-link"
exit

interface gigabitethernet 1/0/48
channel-group 40 mode active
description "MLAG-Partner-Link"
exit

interface range gi1/0/xx-yy
switchport mode access
switchport access vlan 30
exit

feature vpc
vpc domain 1
peer-keepalive enable
exit

switchport trunk native vlan 30
vpc 30
exit

interface port-channel 40
switchport mode trunk
switchport trunk native vlan 30
vpc 40
exit

interface gigabitethernet 1/0/11
channel-group 30 mode active
description "MLAG-Partner-Link"
exit

interface gigabitethernet 1/0/12
channel-group 40 mode active
description "MLAG-Partner-Link"
exit

interface range gi1/0/xx-yy
switchport mode access
switchport access vlan 30
exit

feature vpc
vpc domain 1
peer-keepalive enable
exit

 Must use a native VLAN
 Assign a unique id for partner

switch A

 Create a LAG (port-channel) for
partner switch B to pass traffic

 Assign a unique id for partner
switch B

 Assign interfaces to connect to
partner A LAG (channel-group)

 Assign interfaces to connect to
partner B LAG (channel-group)

 Assign additional ports to the
VLAN only for hosts that will be
using the MLAG

 Enable the MLAG

Partner Switch A

Partner Switch B

Description of commands

configure
vlan 30
exit

interface port-channel 1
switchport mode trunk
switchport trunk native vlan 30
exit

interface gi1/0/27
channel-group 1 mode active
exit

interface gi1/0/28
channel-group 1 mode active
exit

interface range gi1/0/xx-yy
switchport mode access
switchport access vlan 30
exit

configure
vlan 30
exit

interface port-channel 1
switchport mode trunk
switchport trunk native vlan 30
exit

interface gi1/0/29
channel-group 1 mode active
exit

interface gi1/0/30
channel-group 1 mode active
exit

interface range gi1/0/xx-yy
switchport mode access
switchport access vlan 30
exit

 create same VLAN on partners

 configure the port channel

trunk for the partner link

 Assign interfaces to MLAG
(channel-group)

 Assign interfaces to MLAG
(channel-group)

 Assign additional ports to the
VLAN only for hosts that will be
using the MLAG

10 Using MLAG in Dell Networks

.

Primary MLAG Peer

Secondary MLAG Peer

show vpc brief

VPC admin status............................... Enabled

Keep-alive admin status................... Enabled

VPC operational status..................... Enabled

Self role................................................ Primary

Peer role.............................................. Secondary

Peer detection admin status........... Disabled

Peer-Link details

-----------------

Interface.................................................. Po1

Peer-link admin status......................... Enabled

Peer-link STP admin status................. Disabled

Configured VLANs................................. 1,30

Egress tagged VLANs............................ 30

VPC Details

-----------

Number of VPCs configured...................... 2

Number of VPCs operational..................... 2

VPC id# 30

-----------

Interface.................................................... Po30

Configured VLANs.................................. 1,30

VPC interface state................................. Active

Local Members Status

----------------- -----­Gi1/0/47 Up

Peer Members Status

---------------- -----­Gi1/0/11 Up

VPC id# 40

show vpc brief

VPC admin status................................... Enabled

Keep-alive admin status....................... Enabled

VPC operational status......................... Enabled

Self role.................................................. Secondary

Peer role................................................ Primary

Peer detection admin status............... Disabled

Peer-Link details

-----------------

Interface.................................................. Po1

Peer-link admin status......................... Enabled

Peer-link STP admin status................. Disabled

Configured VLANs................................. 1,30

Egress tagged VLANs............................ 30

VPC Details

-----------

Number of VPCs configured...................... 2

Number of VPCs operational..................... 2

VPC id# 30

-----------

Interface.................................................... Po30

Configured VLANs.................................. 1,30

VPC interface state................................. Active

Local Members Status

----------------- -----­Gi1/0/11 Up

Peer Members Status

---------------- -----­< * run command from Primary for this information >

VPC id# 40

Note: Interfaces used to connect each peer to the partner switch LAG do not need to match on each
peer. For instance, in the example above, one partner LAG interface connects to 1/0/47 on the primary
peer while the other interface connects to 1/0/11 on the secondary peer.

2. Connect all cables as shown in Figure 4.

3. Run the show vpc brief command on either of the two MLAG peers to see which

peer is the primary MLAG peer.

4. Run the show vpc brief command again from the primary switch to display all

information for both peers.

Note: The partner switches must be configured with MLAGs and connected to the MLAG peers, or the
“Number of VPCs operational” in the show vpc brief command shows 0.

11 Using MLAG in Dell Networks

.

Primary MLAG Peer

Secondary MLAG Peer

-----------

Interface.............................................. Po40

Configured VLANs............................ 1,30

VPC interface state........................... Active

Local Members Status

----------------- -----­Gi1/0/48 Up

Peer Members Status

---------------- -----­Gi1/0/12 Up

-----------

Interface............................................ Po40

Configured VLANs.......................... 1,30

VPC interface state......................... Active

Local Members Status

----------------- -----­Gi1/0/12 Up

Peer Members Status

---------------- -----­< * run command from Primary for this information >

Single-tier MLAG Peer

show interface port-channel 40

Channel Ports Ch-Type Hash Type Min-links Local Prf

------- ----------------------------- -------- --------- --------- ---­Po40 Active: Gi1/0/48 Dynamic 7 1 Disabled

Hash Algorithm Type
1 - Source MAC, VLAN, EtherType, source module and port Id
2 - Destination MAC, VLAN, EtherType, source module and port Id
3 - Source IP and source TCP/UDP port
4 - Destination IP and destination TCP/UDP port
5 - Source/Destination MAC, VLAN, EtherType, source MODID/port
6 - Source/Destination IP and source/destination TCP/UDP port
7 - Enhanced hashing mode

Note: Running the show vpc brief command on the primary shows the complete status of both peer
switches. Running the show vpc brief command on the secondary only shows the status of the
secondary.

Results of the command should be the same as shown above. All member ports must show “UP”, and the
“VPC interface state” must show “Active”. The show interface port-channel is another helpful tool to
let you know if the configured LAG ports are up and running. This command can be run on both the
primary and secondary peers on a single layer MLAG topology. If correctly configured, the port(s) in the
LAG are listed with an Active status. If there are any inactive ports, check for cabling or configuration
issues.

12 Using MLAG in Dell Networks

.

2 tier

(2 layer, full mesh)

Peer-Link

= MLAG

Stack No.

1

2

1 2SFP+

3 5 7 9 11

4 6 8 10 12

13 15 17 19 21

14 16 18 20 22 24

LNK ACT

1

2

COMBO P

23

LNK ACT

Stack No.

1

2

1 2SFP+

3 5 7 9 11

4 6 8 10 12

13 15 17 19 21

14 16 18 20 22 24

LNK ACT

1

2

COMBO P

23

LNK ACT

Stack No.

1

2

1 2SFP+

3 5 7 9 11

4 6 8 10 12

13 15 17 19 21

14 16 18 20 22 24

LNK ACT

1

2

COMBO P

23

LNK ACT

Stack No.

1

2

1 2SFP+

3 5 7 9 11

4 6 8 10 12

13 15 17 19 21

14 16 18 20 22 24

LNK ACT

1

2

COMBO P

23

LNK ACT

Stack No.

1

2

1 2SFP+

3 5 7 9 11

4 6 8 10 12

13 15 17 19 21

14 16 18 20 22 24

LNK ACT

1

2

COMBO P

23

LNK ACT

Stack No.

1

2

1 2SFP+

3 5 7 9 11

4 6 8 10 12

13 15 17 19 21

14 16 18 20 22 24

LNK ACT

1

2

COMBO P

23

LNK ACT

A.

B.

E.

D.

C.

F.

Peer-Link

Stack No.

1

2

1 2SFP+

3 5 7 9 11

4 6 8 10 12

13 15 17 19 21

14 16 18 20 22 24

LNK ACT

1

2

COMBO P

23

LNK ACT

Stack No.

1

2

1 2SFP+

3 5 7 9 11

4 6 8 10 12

13 15 17 19 21

14 16 18 20 22 24

LNK ACT

1

2

COMBO P

23

LNK ACT

Stack No.

1

2

1 2SFP+

3 5 7 9 11

4 6 8 10 12

13 15 17 19 21

14 16 18 20 22 24

LNK ACT

1

2

COMBO P

23

LNK ACT

Stack No.

1

2

1 2SFP+

3 5 7 9 11

4 6 8 10 12

13 15 17 19 21

14 16 18 20 22 24

LNK ACT

1

2

COMBO P

23

LNK ACT

Stack No.

1

2

1 2SFP+

3 5 7 9 11

4 6 8 10 12

13 15 17 19 21

14 16 18 20 22 24

LNK ACT

1

2

COMBO P

23

LNK ACT

Stack No.

1

2

1 2SFP+

3 5 7 9 11

4 6 8 10 12

13 15 17 19 21

14 16 18 20 22 24

LNK ACT

1

2

COMBO P

23

LNK ACT

Server

PC

A.

B.

C.

D.

E.

F.

(13-14)

(23)

(14)

(13)

(13-14)

(13)

(14)

(1-2)

(1-2)

(1-2)

(1-2)

(24)

(Te 1)

(Te 1)

(Te 1)

(Te 1)

Ports are denoted by the

port # in parenthesis.

Example:

gigabitethernet 1/0/23

is shown as (23)

5 Two-Tier Example

Figure 5 shows a logical topology for a 2-tier fully meshed MLAG, offering full redundancy across all four
MLAG peers. Six Dell N3024s are used for the example, however the same principals apply and the same
commands can be used on the N2000 and N4000 series switches.

Figure 6 shows the physical layout of the same topology as it might appear in a rack, including cabling and
attached hosts that need to communicate across the MLAG. The same color scheme is used for the cables
in Figure 6 that was used to show logical connections in Figure 5.

13 Using MLAG in Dell Networks

.

Logical topology of a 2-tier full mesh configuration Figure 5

Physical cabling of a 2-tier full mesh configuration Figure 6

MLAG Peer B

MLAG Peer C

Description of commands

configure
vlan 30
exit

interface port-channel 1
description "MLAG-Peer-Link"
spanning-tree disable
switchport mode trunk
vpc peer-link
exit

interface tengigabitethernet 1/0/1
channel-group 1 mode active
description "MLAG-Peer-Link"
exit

interface port-channel 40
switchport mode trunk
switchport trunk native vlan 30
vpc 40
exit

interface port-channel 50
switchport mode trunk
switchport trunk native vlan 30
vpc 50
exit

configure
vlan 30
exit

interface port-channel 1
description "MLAG-Peer-Link"
spanning-tree disable
switchport mode trunk
vpc peer-link
exit

interface tengigabitethernet 1/0/1
channel-group 1 mode active
description "MLAG-Peer-Link"
exit

interface port-channel 40
switchport mode trunk
switchport trunk native vlan 30
vpc 40
exit

interface port-channel 50
switchport mode trunk
switchport trunk native vlan 30
vpc 50
exit

 Create a VLAN for MLAG and
all partner traffic

 Configure the port channel for
the BC peer link

- must be trunk mode

 Identify and configure the BC
peer link interfaces

 Create a LAG (port-channel)
for partner switch DE to pass
traffic
 Assign a unique id for partner
switch DE

 Create a LAG (port-channel)
for partner switch A to pass
traffic
 Assign a unique id for partner
switch A

In a full mesh, all eight ports joined together in the MLAG (four blue cables) are in the same port channel
to achieve maximum redundancy.

To configure the 2-tier in a full mesh configuration, follow the steps below:

1. Enter the commands below for each corresponding switch in the topology.

2. Cable the configuration as shown.

3. Enable MLAG (using the feature vpc command) on each switch.

Similar commands are performed on all four MLAG peer switches. MLAG peers B and C are required to be
consistent in their configurations following the guidelines set in

Consistency of MLAG peers

. MLAG peers
D and E also follow the same requirements for consistency. Though MLAG partner switches A and F may
have similar configurations in this particular scenario, they have no such consistency requirements to each
other or to the peer switches.

Each column below contains commands that can be cut and pasted into a CLI session if using the same
topology as described in this example. Command sections are color-coded to allow easier comparisons
between the BC MLAG peers and the

DE

MLAG peers.

14 Using MLAG in Dell Networks

.

MLAG Peer B

MLAG Peer C

Description of commands

interface gigabitethernet 1/0/1
channel-group 40 mode active
description "MLAG-Partner-Link"
exit

interface gigabitethernet 1/0/2
channel-group 40 mode active
description "MLAG-Partner-Link"
exit

interface gigabitethernet 1/0/14
channel-group 50 mode active
switchport mode trunk
switchport trunk allowed vlan 30
exit

feature vpc
vpc domain 1
peer-keepalive enable
exit

interface gigabitethernet 1/0/1
channel-group 40 mode active
description "MLAG-Partner-Link"
exit

interface gigabitethernet 1/0/2
channel-group 40 mode active
description "MLAG-Partner-Link"
exit

interface gigabitethernet 1/0/13
channel-group 50 mode active
switchport mode trunk
switchport trunk allowed vlan 30
exit

feature vpc
vpc domain 1
peer-keepalive enable
exit

 Assign interfaces to connect
to partner E’s half of full mesh
LAG

 Assign interfaces to connect
to partner D’s half of full mesh
LAG

 Assign interfaces to VLAN that
will connect to partner A’s LAG

-put both 13 and 14 into same
LAG 50

 Enable the MLAG

MLAG Peer D

MLAG Peer E

Description of commands

configure
vlan 30
exit

interface port-channel 1
description "MLAG-Peer-Link"
spanning-tree disable
switchport mode trunk
vpc peer-link
exit

interface tengigabitethernet 1/0/1
channel-group 1 mode active
description "MLAG-Peer-Link"
exit

interface port-channel 40
switchport mode trunk
switchport trunk native vlan 30
vpc 40
exit

interface port-channel 60
switchport mode trunk
switchport trunk native vlan 30
vpc 60
exit

interface gigabitethernet 1/0/1
channel-group 40 mode active

configure
vlan 30
exit

interface port-channel 1
description "MLAG-Peer-Link"
spanning-tree disable
switchport mode trunk
vpc peer-link
exit

interface tengigabitethernet 1/0/1
channel-group 1 mode active
description "MLAG-Peer-Link"
exit

interface port-channel 40
switchport mode trunk
switchport trunk native vlan 30
vpc 40
exit

interface port-channel 60
switchport mode trunk
switchport trunk native vlan 30
vpc 60
exit

interface gigabitethernet 1/0/1
channel-group 40 mode active

 Create a VLAN for MLAG and
all partner traffic

 Configure the port channel for
the DE peer link

- must be trunk mode

 Identify and configure the DE
peer link interfaces

 Create a LAG (port-channel)
for partner switch BC to pass
traffic
 Assign a unique id for partner
switch BC

 Create a LAG (port-channel)
for partner switch F to pass traffic

 Assign a unique id for partner
switch F

 Assign interfaces to connect
to partner B ‘s half of full mesh

15 Using MLAG in Dell Networks

.

MLAG Peer D

MLAG Peer E

Description of commands

description "MLAG-Partner-Link"
exit

interface gigabitethernet 1/0/2
channel-group 40 mode active
description "MLAG-Partner-Link"
exit

interface gigabitethernet 1/0/14
channel-group 60 mode active
switchport mode trunk
switchport trunk allowed vlan 30
description "MLAG-Partner-Link"
exit

feature vpc
vpc domain 1
peer-keepalive enable
exit

description "MLAG-Partner-Link"
exit

interface gigabitethernet 1/0/2
channel-group 40 mode active
description "MLAG-Partner-Link"
exit

interface gigabitethernet 1/0/13
channel-group 60 mode active
switchport mode trunk
switchport trunk allowed vlan 30
description "MLAG-Partner-Link"
exit

feature vpc
vpc domain 1
peer-keepalive enable
exit

MLAG

 Assign interfaces to connect
to partner C ‘s half of full mesh
LAG

 Assign interfaces to VLAN that
will connect to partner F’s LAG

-put both 13 and 14 into same
LAG 60

 Enable the MLAG

Partner Switch A

Partner Switch F

Description of commands

configure
vlan 30
exit

interface port-channel 1
switchport mode trunk
exit

interface gi1/0/13
channel-group 1 mode active
exit

interface gi1/0/14
channel-group 1 mode active
exit

interface gi1/0/23
switchport mode access
switchport access vlan 30
exit

configure
vlan 30
exit

interface port-channel 1
switchport mode trunk
exit

interface gi1/0/13
channel-group 1 mode active
exit

interface gi1/0/14
channel-group 1 mode active
exit

interface gi1/0/24
switchport mode access
switchport access vlan 30
exit

 create same VLAN on partners

 configure the port channel

trunks for the partner links

 Assign first interface to LAG
(channel-group)

 Assign second interface to
LAG (channel-group)

 Assign additional ports to the
VLAN only for hosts that will be
using the MLAG

16 Using MLAG in Dell Networks

.

Port 23 in switch A connects to the Server, and port 24 in switch F connects to the PC client.

Connect all cables as shown in Figure 6.

Run the show vpc brief command on either of the two MLAG peers to see which peer is the primary
MLAG peer. Run the show vpc brief command again from the primary switch to display all information
for both peers.

MLAG Peer B (Primary Peer)

MLAG Peer C (Secondary Peer)

show vpc brief

VPC admin status................................... Enabled

Keep-alive admin status....................... Enabled

VPC operational status......................... Enabled

Self role.................................................... Primary

Peer role.................................................. Secondary

Peer detection admin status............... Disabled

Peer-Link details

-----------------

Interface.................................................. Po1

Peer-link admin status......................... Enabled

Peer-link STP admin status................. Disabled

Configured VLANs................................ 1,30

Egress tagged VLANs............................ 30

VPC Details

-----------

Number of VPCs configured...................... 2

Number of VPCs operational..................... 2

VPC id# 40

-----------

Interface................................................ Po40

Configured VLANs............................... 1,30

VPC interface state............................. Active

Local Members Status

----------------- -----­Gi1/0/1 Up
Gi1/0/2 Up

Peer Members Status

---------------- -----­Gi1/0/1 Up
Gi1/0/2 Up

VPC id# 50

-----------

Interface................................................ Po50

Configured VLANs............................... 1,30

VPC interface state............................. Active

show vpc brief

VPC admin status................................... Enabled

Keep-alive admin status........................ Enabled

VPC operational status.......................... Enabled

Self role..................................................... Secondary

Peer role................................................... Primary

Peer detection admin status................ Disabled

Peer-Link details

-----------------

Interface.................................................. Po1

Peer-link admin status......................... Enabled

Peer-link STP admin status................. Disabled

Configured VLANs................................. 1,30

Egress tagged VLANs............................ 30

VPC Details

-----------

Number of VPCs configured...................... 2

Number of VPCs operational..................... 2

VPC id# 40

-----------

Interface................................................ Po40

Configured VLANs............................... 1,30

VPC interface state............................. Active

Local Members Status

----------------- -----­Gi1/0/1 Up
Gi1/0/2 Up

Peer Members Status

---------------- -----­< * run command from Primary for this information >

VPC id# 50

-----------

Interface................................................ Po50

Configured VLANs............................... 1,30

VPC interface state............................. Active

Note: Interfaces used to connect each peer to the partner switch LAG do not need to match on each
peer. For instance, in the example above, one partner LAG interface connects to 1/0/47 on the primary
peer while the other interface connects to 1/0/11 on the secondary peer.

Note: The partner switches must be configured with LAGs and connected to the MLAG peers, or the
“Number of VPCs operational” in the show vpc brief command will show 0.

17 Using MLAG in Dell Networks

.

Local Members Status

----------------- -----­Gi1/0/14 Up

Peer Members Status

---------------- -----­Gi1/0/13 Up

Local Members Status

----------------- -----­Gi1/0/13 Up

Peer Members Status

---------------- ------
< * run command from Primary for this information >

MLAG Primary Peers only:

B and D

show interface port-channel 40

Channel Ports Ch-Type Hash Type Min-links Local Prf

------- ----------------------------- -------- --------- --------- ---­Po40 Active: Gi1/0/1, Gi1/0/2 Dynamic 7 1 Disabled

Hash Algorithm Type
1 - Source MAC, VLAN, EtherType, source module and port Id
2 - Destination MAC, VLAN, EtherType, source module and port Id
3 - Source IP and source TCP/UDP port
4 - Destination IP and destination TCP/UDP port
5 - Source/Destination MAC, VLAN, EtherType, source MODID/port
6 - Source/Destination IP and source/destination TCP/UDP port
7 - Enhanced hashing mode

Note: Running the show vpc brief command on the primary shows the complete status of both peer
switches. Running the show vpc brief command on the secondary shows status of the secondary
only.

Results of the command should be the same as shown above. All member ports must show “UP”, and the
“VPC interface state” must show “Active”. The show interface port-channel is another helpful tool to
let you know if the configured LAGs are up and running. This command must also only be run on the
primary peer when used in a two-tier topology. If correctly configured, ports in the primary LAG are listed
with an “Active” status. Inactive ports are usually a sign of a cabling or configuration issue.

Like the show vpc brief command, the show interfaces port-channel command must be run
from the primary peer to receive information from both of the peer switches.

18 Using MLAG in Dell Networks

.

LAG

N3048

N3048

Peer-

Link

MLAG

VLTi

S4810

S4810

QSFP+

MASTER

SYS

FAN

PSU

RS-232

ETHERNET

LNK ACT

4644424038363432302826242220181614121086420 48 56

52 60

SFP+

Force10 S4810P

QSFP+

MASTER

SYS

FAN

PSU

RS-232

ETHERNET

LNK ACT

4644424038363432302826242220181614121086420 48 56

52 60

SFP+

Force10 S4810P

LAG

LAG

N3048

N3048

vPC

Cisco

Cisco

LAG

LAG

LAG

CISCO NEXUS 2232TP 10GE FABRIC EXTENDER

STAT

2526 2728 2930 31 321718 1920 2122 23 249 10 1112 13 14 151612 3 4 5 6 78

ID

1 2 34 5 6 78

CISCO NEXUS 2232TP 10GE FABRIC EXTENDER

STAT

2526 2728 2930 31 321718 1920 2122 23 249 10 1112 13 14 151612 3 4 5 6 78

ID

1 2 34 5 6 78

All 4 orange ports

are in the same

port-channel

All 4 green ports

are in the same

port-channel

All 4 orange ports

are in the same

port-channel

All 4 green ports

are in the same

port-channel

Note: Orange and green are
in different port-channels in

both examples

Peer-

Link

MLAG

N3048

Peer-Link

LAG

VLTi

S4810

QSFP+

MASTER

SYS

FAN

PSU

RS-232

ETHERNET

LNK ACT

4644424038363432302826242220181614121086420 48 56

52 60

SFP+

Force10 S4810P

X

Peer-Link

LAG

Cisco

X

vPC

N3048

CISCO NEXUS 2232TP 10GE FABRIC EXTENDER

STAT

2526 2728 2930 31321718 1920 2122 2324910 1112 1314 15161 2 3 4 5 6 78

ID

12 3 4 5 6 7 8

6 Using MLAG with VLT or Cisco vPC

MLAG can also be used in conjuction with similar technologies such as Dell Networking VLT or Cisco vPC
(virtual port-channel), but only in a multi-layer topology. VLT provides the equivalent results as MLAG, but
is available on the FTOS-based Dell Networking switches like the S4810. Each peer pair must use the same
multi-chassis lag feature. This provides the network with the same resiliency and improved bandwidth as
when using MLAG in a multi-tier MLAG-only environment. Figure 7 shows examples of using MLAG peers
on one layer and VLT or Cisco vPC on the other.

6.1 Unsupported Configurations

.

Multi-layer MLAG with VLT and with Cisco vPC Figure 7

Figure 8 and Figure 9 show examples of configurations that are
topology shows an MLAG peer attempting to connect with a Dell VLTi peer. The second topology shows
an MLAG peer attempting to connect with a Cisco vPC (or Cisco VSS) peer. Neither peer configurations
shown in these scenarios are supported.

Unsupported peer configurations Figure 8

19 Using MLAG in Dell Networks

not supported

. In Figure 8, the first

LAG

N3048

N3048

Peer-

Link

MLAG

VLTi

S4810

S4810

QSFP+

MASTER

SYS

FAN

PSU

RS-232

ETHERNET

LNK ACT

4644424038363432302826242220181614121086420 48 56

52 60

SFP+

Force10 S4810P

QSFP+

MASTER

SYS

FAN

PSU

RS-232

ETHERNET

LNK ACT

4644424038363432302826242220181614121086420 48 56

52 60

SFP+

Force10 S4810P

LAG

N3048

N3048

Peer-

Link

MLAG

vPC

Cisco

Cisco

LAG

CISCO NEXUS 2232TP 10GE FABRIC EXTENDER

STAT

2526 27 28 29 30 31 321718 19 20 21 22 23 249 10 11 12 13 14 15 161 2 3 4 5 6 7 8

ID

1 2 3 4 5 6 7 8

CISCO NEXUS 2232TP 10GE FABRIC EXTENDER

STAT

2526 27 28 29 30 31 321718 19 20 21 22 23 249 10 11 12 13 14 15 161 2 3 4 5 6 7 8

ID

1 2 3 4 5 6 7 8

LAG

X

X

In Figure 9 below, the first topology shows MLAG peers on one layer and Dell VLT peers on the second
layer, with a full-mesh LAG. The second topology shows MLAG peers on one layer and Cisco vPC (or
Cisco VSS) on the second layer, also with a full-mesh LAG. Neither full mesh configuration shown in these
scenarios is compatible.

Unsupported LAG configurations Figure 9

When using MLAG in a full-mesh LAG, no other peer technology can be used. To use another peer
technology on a second layer, LAGs must be configured only on the MLAG peer switches (like in Figure 7).
or only on the other peer switches that are using Dell VLTi or Cisco vPC. Either side works as long as both
LAGs are created on the same peer set.

20 Using MLAG in Dell Networks

.

A Additional Resources

Support.dell.com is focused on meeting your needs with proven services and support.

DellTechCenter.com is an IT Community where you can connect with Dell Customers and Dell
employees for the purpose of sharing knowledge, best practices, and information about Dell products and
installations.

Referenced or recommended Dell publications:

 Dell Networking Support

- http://www.dell.com/support

 Dell TechCenter (community forums and blogs for Dell customers)

- http://delltechcenter.com

 Dell Networking Whitepapers

- http://en.community.dell.com/techcenter/networking/w/wiki/2580.networking-

whitepapers.aspx

 Dell Networking N2000/N3000/N4000 User Guides and Firmware downloads

- http://www.dell.com/support/my-

support/us/en/04#04/Products/ser_stor_net/networking?&_suid=138471814600402061940321
9436666

21 Using MLAG in Dell Networks

.

Component

Description

Dell Networking firmware versions

D.9.29.2, 6.0.0.2, 6.0.0.4

Switch

Dell Networking N2000, N3000, and N4000 series

B Configuration details

This paper was compiled using the following components and versions.

About Dell

Dell is a worldwide leader in data center and campus solutions which includes the manufacturing and
distribution of servers, network switches, storage devices, personal computers, and related hardware and
software. For more information on these and other products, please visit the Dell website at

http://www.dell.com.

22 Using MLAG in Dell Networks

.