HP 12500 Series User manual

HP 12500 Routing Switch Series
IRF
Configuration Guide
Part number: 5998-3408
Document version: 6W710-20121130
Software version: 12500-CMW710-R7128

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© Copyright 2012 Hewlett-Packard Development Company, L.P.
No part of this documentation may be reproduced or transmitted in any form or by any means
without prior written consent of Hewlett-Packard Development Company, L.P.
The information contained herein is subject to change without notice.
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additional warranty. HP shall not be liable for technical or editorial errors or omissions contained
herein.

i
Contents
IRF overview································································································································································································· 1
Hardware compatibility··············································································································································································1
IRF benefits ·····································································································································································································1
Application scenario····················································································································································································1
Network topologies·····················································································································································································2
Basic concepts ·······························································································································································································2
Operating mode ·················································································································································································4
IRF member roles ···············································································································································································4
IRF member ID·····················································································································································································5
MPU roles······························································································································································································5
IRF port···································································································································································································5
IRF domain ID ······················································································································································································6
IRF split ···································································································································································································7
IRF merge ······························································································································································································7
Member priority··················································································································································································7
Master election······························································································································································································7
IRF multi-active detection·········································································································································································8
Multi-active handling procedure ·················································································································································8
LACP MAD·····························································································································································································9
BFD MAD ·····························································································································································································10
ARP MAD·····························································································································································································11
Configuring IRF·························································································································································································13
General restrictions and configuration guidelines························································································································13
Software requirements···································································································································································13
IRF fabric size ·····················································································································································································13
MPU and IRF port restrictions·····················································································································································13
IRF link redundancy·········································································································································································13
Feature and IRF mode compatibility ········································································································································13
MAD·······································································································································································································14
Other configuration guidelines ··················································································································································14
Setup and configuration task list ·························································································································································14
Planning the IRF fabric setup·································································································································································15
Preconfiguring IRF member devices in standalone mode·········································································································16
Assigning a member ID to each IRF member device ········································································································16
Specifying a priority for each member device ·····················································································································16
Binding physical ports to IRF ports···········································································································································16
Enabling enhanced IRF mode in standalone mode······················································································································17
Saving configuration to the next-startup configuration file·····································································································18
Connecting IRF physical ports·······························································································································································18
Setting the operating mode to IRF mode ········································································································································19
Accessing the IRF fabric ···········································································································································································20
Configuring IRF member devices in IRF mode·······························································································································20
Assigning an IRF domain ID to the IRF fabric·······················································································································20
Changing the member ID of a device······································································································································21
Changing the priority of a member device ···························································································································22
Adding physical ports to an IRF port ·······································································································································22
Enabling enhanced IRF mode in IRF mode····························································································································24
Enabling auto reboot for IRF fabric merge····························································································································25

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Configuring a member device description ····························································································································25
Configuring IRF bridge MAC persistence·······························································································································25
Enabling software auto-update for system software image synchronization·························································26
Setting the IRF link down report delay····································································································································27
Enabling IRF link failure detection and auto-recovery······································································································28
Configuring MAD ·············································································································································································28
Fast-restoring IRF configuration for a one-MPU member ········································································································36
Displaying and maintaining an IRF fabric·········································································································································37
Configuration examples···········································································································································································38
LACP MAD-enabled IRF configuration example for a two-chassis IRF fabric ·························································38
BFD MAD-enabled IRF configuration example for a two-chassis IRF fabric····························································42
ARP MAD-enabled IRF configuration example for a two-chassis IRF fabric····························································45
Enhanced IRF mode configuration example ·························································································································47
Restoring standalone mode ························································································································································52
Index ·············································································································································································································55

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IRF overview
The HP Intelligent Resilient Framework (IRF) technology creates a large switching system called an
"IRF fabric" from multiple devices to provide data center class availability and scalability. IRF
virtualization technology offers processing power, interaction, unified management, and
uninterrupted maintenance of multiple devices.
This book describes IRF concepts and guides you through the IRF setup procedure.
Hardware compatibility
An HP 12500 switch can form an IRF fabric only with devices in the same series.
IRF benefits
IRF delivers the following benefits:
•Simplified topology and easy management—An IRF fabric appears as one node and is
accessible at a single IP address on the network. You can use this IP address to log in at any
member device to manage all the members of the IRF fabric. In addition, you do not need to
run the spanning tree feature among the IRF members.
•1:N redundancy—In an IRF fabric, one member works as the master to manage and control
the entire IRF fabric, and all other members process services while backing up the master.
When the master fails, all the other member devices elect a new master from among them to
take over without interrupting services.
•IRF link aggregation—You can assign several physical links between neighboring members to
their IRF ports to create a load-balanced aggregate IRF connection with redundancy.
•Multiple-chassis link aggregation—You can use the Ethernet link aggregation feature to
aggregate the physical links between the IRF fabric and its upstream or downstream devices
across the IRF members.
•Network scalability and resiliency—Processing capacity of an IRF fabric equals the total
processing capacities of all the members. You can increase ports, network bandwidth, and
processing capacity of an IRF fabric simply by adding member devices without changing the
network topology.
Application scenario
Figure 1 shows an IRF fabric that comprises two devices, which appear as a single node to the
upper and lower layer devices.

2
Figure 1 IRF application scenario
Network topologies
An IRF fabric can use a daisy chain topology or a ring topology. Full mesh topology is not
supported. For information about connecting IRF member devices, see "Connecting IRF physical
ports."
Basic concepts
This section uses Figure 2 to describe the basic concepts that you might encounter when working
with IRF.
IP network
IRF
IP network
IRF link Equal to
Master Standby

3
Figure 2 Two-chassis IRF fabric implementation schematic diagram
In this figure, Device A and Device B form a two-chassis IRF fabric that has four MPUs (one active
and three standbys) and two times the number of interface cards that a single device provides. The
IRF fabric manages the physical and software resources of Device A and Device B in a centralized
manner.
You can scale this two-chassis IRF fabric to a four-chassis IRF fabric for higher port density and
availability, as shown in Figure 3.

4
Figure 3 Four-chassis IRF fabric implementation schematic diagram
Operating mode
The device operates in one of the following modes:
•Standalone mode—The device cannot form an IRF fabric with other devices.
•IRF mode—The device can form an IRF fabric with other devices.
IRF member roles
IRF uses two member roles: master and standby.
When devices form an IRF fabric, they elect a master to manage and control the IRF fabric, and all
standby devices back up the master. When the master device fails, the standby devices

5
automatically elect a new master from among them to take over. For more information about
master election, see "Master election."
While backing up the master, all standby devices process and forward traffic independently.
IRF member ID
An IRF fabric uses member IDs to uniquely identify and manage its members. If two devices have
the same IRF member ID, they cannot form an IRF fabric. If the IRF member ID of a device has been
used in an IRF fabric, the device cannot join the fabric.
Member ID information is included as the first part of interface numbers and file paths to uniquely
identify interfaces and files in an IRF fabric. For example, after you assign a device with member ID
2 to an IRF fabric, the name of interface GigabitEthernet 3/0/1 changes to GigabitEthernet 2/3/0/1,
and the file path slot1#flash:/test.cfg changes to chassis2#slot1#flash:/test.cfg.
By default, the standby MPU of a device is automatically assigned the same ID as the active MPU.
You can change the standby MPU ID of one member device to quickly recover IRF configuration for
another member device that has only one MPU, as described in "Fast-restoring IRF configuration
for a one-MPU member."
MPU roles
Each IRF member device has one or two MPUs, which play different roles, as follows:
Role Description
Master MPU
Active MPU of the master device. It is also called the "global active MPU" in
Comware 5 documentation. You configure and manage the entire IRF fabric
at the CLI of the master MPU.
Active MPU
Active MPU on each member device. An active MPU has the following
responsibilities:
•Manages the local device, including synchronizing configuration with the
local standby MPU, processing protocol packets, and creating and
maintaining route entries.
•Handles IRF related events, such as master election and topology
collection.
Standby MPU
For the master MPU, all other MPUs, including active MPUs on standby
devices, are standby MPUs.
If a member device has two MPUs, the one backing up the local active MPU
is the local standby MPU from the perspective of the member device. A local
standby MPU does not process traffic.
IRF port
An IRF port is a logical interface for the connection between IRF member devices. Every IRF-capable
device supports two IRF ports. They forward IRF protocol packets and data packets that must travel
across IRF member devices.
In standalone mode, the IRF ports are named IRF-port 1 and IRF-port 2.

6
In IRF mode, the IRF ports are named IRF-port n/1 and IRF-port n/2, where nis the member ID of
the device. The two IRF ports are referred to as "IRF-port 1" and "IRF-port 2" in this book for
simplicity.
To use an IRF port, you must bind at least one physical port to it. These ports are called "IRF
physical ports."
The physical ports assigned to an IRF port automatically form an aggregate IRF link. An IRF port
goes down only if all its member physical ports are down.
For two neighboring devices, their IRF physical links must be bound to IRF-port 1 on one device
and to IRF-port 2 on the other.
IRF domain ID
One IRF fabric forms one IRF domain. IRF uses IRF domain IDs to uniquely identify IRF fabrics and
prevent IRF fabrics from interfering with one another.
As shown in Figure 4, Device A and Device B form IRF fabric 1, and Device C and Device D form IRF
fabric 2. Both fabrics use the LACP aggregate links between them for MAD. When a member device
in one IRF fabric receives an extended LACP packet for MAD, it looks at the domain ID in the packet
to see whether the packet is from the local IRF fabric or from a different IRF fabric. Then, the device
can handle the packet correctly.
Figure 4 A network that comprises two IRF domains

7
IRF split
IRF split occurs when an IRF fabric breaks up into two or more IRF fabrics because of IRF link
failures, as shown in Figure 5. The split IRF fabrics operate with the same IP address and cause
routing and forwarding problems on the network.
To avoid a card removal causing an IRF split, bind physical ports on different cards to an IRF port.
Figure 5 IRF split
IRF merge
IRF merge occurs when split IRF fabrics re-unite or when two independent IRF fabrics are united, as
shown in Figure 6.
Figure 6 IRF merge
Member priority
Member priority determines the possibility of a member device to be elected the master. A member
with higher priority is more likely to be elected the master.
The default member priority is 1. You can change the member priority of a device to affect the
master election result.
Master election
Master election is held each time the IRF fabric topology changes, for example, when the IRF fabric
is established, the master device fails or is removed, the IRF fabric splits, or two active IRF fabrics
merge.
Master election uses the following rules in descending order:
1. Current master, even if a new member has higher priority.
When an IRF fabric is being formed, all member devices consider themselves as the master,
and this rule is skipped.
2. Member with higher priority.
3. Member with the longest system uptime.
IRF link
XGE1/3/0/1 XGE2/3/0/1
Device A Device B
Device A Device B
IRF 1 IRF 2 IRF
+=

8
Two members are considered starting up at the same time if their startup time difference is
equal to or less than 10 minutes. For these members, the next tiebreaker applies.
4. Member with the lowest member ID.
When master election is complete, the devices that fail the master election must reboot to rejoin
the IRF fabric that wins the election. The reboot can be automatically performed or must be
manually performed, depending on the configuration. See "Enabling auto reboot for IRF fabric
merge."
After a master election, all standby devices reboot with the configuration on the master, and their
original next-startup configuration files do not take effect.
IRF multi-active detection
An IRF link failure causes an IRF fabric to split in two IRF fabrics operating with the same Layer 3
configurations, including the same IP address. To avoid IP address collision and network problems,
IRF uses multi-active detection (MAD) mechanisms to detect the presence of multiple identical IRF
fabrics, handle collisions, and recover from faults.
Multi-active handling procedure
The multi-active handling procedure includes detection, collision handling and failure recovery.
Detection
The MAD implementation of this device detects active IRF fabrics with the same Layer 3 global
configuration by extending the LACP, BFD, or ARP protocol.
These MAD mechanisms identify each IRF fabric with a domain ID and an active ID (the member ID
of the master). If multiple active IDs are detected in a domain, MAD determines that an IRF collision
or split has occurred.
You can use at least one of these mechanisms in an IRF fabric, depending on your network
topology.
IMPORTANT:
LACP MAD handles collisions in a different way than BFD MAD and
A
RP MAD. To avoid conflicts,
do not enable LACP MAD together with BFD MAD or
A
RP MAD in an IRF fabric. However, you can
use BFD MAD and ARP MAD together.
For a comparison of these MAD mechanisms, see "Configuring MAD."
Collision handling
MAD mechanisms remove multi-active collisions by setting one IRF fabric to the Active state and
other IRF fabrics to the Recovery state. Only members in the Active-state fabric can continue to
forward traffic.
LACP MAD handles a multi-active collision in the following procedure:
1. Compares the number of members in each fabric.
2. Sets the fabric that has the most members to the Active state and all other fabrics to the
Recovery state.
3. If all IRF fabrics have the same number of members, compares the member IDs of their
masters.

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4. Sets the IRF fabric that has the lowest numbered master to the Active state and all other
fabrics to the Recovery (disabled) state.
5. Shuts down all physical network ports in the Recovery-state fabrics but their physical IRF ports
and any ports you have specified with the mad exclude interface command.
In contrast, BFD MAD and ARP MAD do not compare the number of members in fabrics. They
directly set the IRF fabric that has the lowest numbered master to the Active state, set all other
fabrics to the Recovery state, and take the same action on the network ports in Recovery-state
fabrics as LACP MAD does.
Failure recovery
To merge two split IRF fabrics, first repair the failed IRF link and remove the IRF link failure.
If the IRF fabric in Recovery state fails before the failure is recovered, repair the failed IRF fabric and
the failed IRF link.
If the IRF fabric in Active state fails before the failure is recovered, first enable the IRF fabric in
Recovery state to take over the active IRF fabric and protect services from being affected. After that,
recover the MAD failure.
LACP MAD
LACP MAD requires that every IRF member have a link with an intermediate device, and all these
links form a dynamic link aggregation group, as shown in Figure 7. In addition, the intermediate
device must be an HP device that supports extended LACP for MAD.
The IRF member devices send extended LACPDUs with TLVs that convey the domain ID and the
active ID of the IRF fabric. The intermediate device transparently forwards the extended LACPDUs
received from one member device to all the other member devices:
•If the domain IDs and the active IDs in the extended LACPDUs sent by all the member devices
are the same, the IRF fabric is integrated.
•If the extended LACPDUs convey the same domain ID but different active IDs, a split has
occurred. To handle this situation, LACP MAD sets the IRF fabric with higher active ID in
Recovery state, and shuts down all its physical ports but the console ports, IRF ports, and any
ports you have specified with the mad exclude interface command. The IRF fabric with lower
active ID is still in Active state and forwards traffic.

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Figure 7 LACP MAD application scenario
BFD MAD
BFD MAD can work with or without intermediate devices. Figure 8 shows a typical BFD MAD
application scenario.
To use BFD MAD:
•Set up dedicated BFD MAD link between each pair of IRF members or between each IRF
member and the intermediate device. Do not use the BFD MAD links for any other purpose.
•Assign the ports connected by BFD MAD links to the same VLAN, create a VLAN interface for
the VLAN, and assign a MAD IP address to each member on the VLAN interface.
The MAD addresses identify the member devices and must belong to the same subnet.
With BFD MAD, the master tries to establish BFD sessions with the other member devices by using
its MAD IP address as the source IP address:
•If the IRF fabric is integrated, only the MAD IP address of the master is effective, and the
master cannot establish a BFD session with any other member. If you execute the display bfd
session command, the state of the BFD sessions is Down.
•When the IRF fabric splits, the IP addresses of the masters in the split IRF fabrics take effect,
and the two masters can establish a BFD session. If you use the display bfd session command,
the state of the BFD session between the two devices is Up.

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Figure 8 BFD MAD application scenario
ARP MAD
ARP MAD detects multi-active collisions by using extended ARP packets that convey the IRF
domain ID and the active ID.
You can set up ARP MAD links between neighbor IRF member devices, or more commonly, between
each IRF member device and an intermediate device (see Figure 9). If an intermediate device is used,
you must also run the spanning tree feature between the IRF fabric and the intermediate device.
Device
Master Standby
IRF
Internet
Customer
premise
network
IRF link
Link aggregation
BFD MAD link
VLAN 2
192.168.1.2/24 VLAN 2
192.168.1.3/24

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Figure 9 ARP MAD application scenario
Each IRF member compares the domain ID and the active ID in incoming extended ARP packets
with its domain ID and active ID:
•If the domain IDs are different, the extended ARP packet is from a different IRF fabric, and the
device does not continue to process the packet with the MAD mechanism.
•If the domain IDs are the same, the device compares the active IDs:
{If the active IDs are different, the IRF fabric has split.
{If the active IDs are the same, the IRF fabric is integrated.

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Configuring IRF
Read the configuration restrictions and guidelines carefully when you connect and set up an IRF
fabric.
General restrictions and configuration guidelines
Software requirements
All IRF member devices must run the same software image version.
IRF fabric size
A 12500 IRF fabric can have up to four chassis.
MPU and IRF port restrictions
•Every IRF member device must have at least one MPU. If you replace MPUs while the IRF fabric
is operating, do not remove all MPUs of a member device.
•If a member device has two MPUs, the MPUs must be the same model.
•Both fiber and copper Ethernet ports can be used for IRF connection. HP recommends using
10-GE fiber ports for high performance.
•When connecting two neighboring IRF members, connect IRF-port 1 on one member to
IRF-port 2 on the other.
Suppose you have four chassis: A, B, C, and D. IRF-port 1 and IRF-port 2 are represented by A1
and A2 on chassis A, represented by B1 and B2 on chassis B, and so on. To connect the four
chassis into a ring: A-B-C-D(A), the IRF links must be A1-B2, B1-C2, C1-D2, and D1-A2; or
A2-B1, B2-C1, C2-D1, and D2-A1.
•If multiple physical links are used between two member chassis, bind them all to IRF-port 1 on
one chassis and to IRF-port 2 on the other. If the number of physical ports at two ends of an
aggregate IRF link differs, the IRF fabric cannot be formed.
IRF link redundancy
•Up to 12 physical ports can be bound to one IRF port for IRF link redundancy. The physical
ports of an IRF port are load shared.
•Physical ports bound to an IRF port can be located on different cards.
•HP recommends using multicard IRF links to avoid a card removal causing an IRF split.
Feature and IRF mode compatibility
To form an IRF fabric:

14
•All member devices in the IRF fabric must use the same ACL hardware mode. For more
information about hardware-based ACLs, see ACL and QoS Configuration Guide.
•All member devices in the IRF fabric must have the same vpn popgo command setting. For
more information about vpn popgo, see MPLS Configuration Guide.
•All member devices in the IRF fabric must have the same irf mode enhanced command
configuration.
•All member devices in the IRF fabric must work in the same system operating mode. For more
information about the system operating mode, see Fundamentals Configuration Guide.
MAD
•LACP MAD handles collisions in a different way than BFD MAD and ARP MAD. To avoid
conflicts, do not enable LACP MAD together with BFD MAD or ARP MAD in an IRF fabric.
However, you can configure BFD MAD and ARP MAD together in an IRF fabric for prompt IRF
split detection.
•If LACP MAD or ARP MAD runs between two IRF fabrics, assign each fabric a unique IRF
domain ID. For BFD MAD, this task is optional.
•To exclude a port from the shutdown action that is executed when an IRF fabric transits to the
Recovery state, use the mad exclude interface command. To bring up a port after the IRF
fabric transits to the Recovery state, you must use the mad restore command to activate the
entire IRF fabric, rather than using the undo shutdown command.
Other configuration guidelines
•If a standby device uses the same next-startup configuration file name as the master device,
the file might be overwritten depending on your configuration file management settings. To
continue to use the configuration file after removing the device from the IRF fabric, back up
the file before setting up the IRF fabric.
•Strictly follow the IRF fabric setup procedure described in "Setup and configuration task list" to
plan the IRF fabric, identify IRF physical ports, connect IRF member devices, and configure
basic settings.
•Assign each member a unique IRF member ID to make sure they can merge. You must reboot
the members to validate the IRF member ID settings.
•If two IRF fabrics have the same bridge MAC address, they cannot merge.
•Assign the highest member priority to the device you want to use as the master.
•Assign the IRF fabric a unique IRF domain ID in a multi-IRF network.
•Save any configuration you have made to the startup configuration file before rebooting the
IRF member devices.
Setup and configuration task list
HP recommends the following IRF fabric setup and configuration procedure:
Setup and configuration procedure Remarks
1. (Required.) Planning the IRF fabric setup N/A

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Setup and configuration procedure Remarks
2. (Required.) Preconfiguring IRF member devices in
standalone mode:
{Assigning a member ID to each IRF member device
{Specifying a priority for each member device
{Binding physical ports to IRF ports
Perform these tasks on each member
device before the IRF mode is enabled.
3. (Optional.) Enabling enhanced IRF mode in standalone
mode
If more than two devices are used to
form one IRF fabric, this step is required.
4. (Required.) Saving configuration to the next-startup
configuration file N/A
5. (Required.) Connecting IRF physical ports Make sure that they are interoperable.
6. (Required.) Setting the operating mode to IRF mode N/A
7. (Required.) Accessing the IRF fabric N/A
8. (Optional.) Configuring IRF member devices in IRF mode:
{Assigning an IRF domain ID to the IRF fabric
{Changing the member ID of a device
{Changing the priority of a member device
{Adding physical ports to an IRF port
{Enabling enhanced IRF mode in IRF mode
{Enabling auto reboot for IRF fabric merge
{Configuring a member device description
{Configuring IRF bridge MAC persistence
{Enabling software auto-update for system software
image synchronization
{Setting the IRF link down report delay
{Enabling IRF link failure detection and auto-recovery
{Configuring MAD
If IRF ports have not been configured
when a member device operating in
standalone mode, you must configure its
IRF ports.
If a two-chassis IRF fabric has new joining
members, you must enable the enhanced
IRF mode.
If a relay device is used, you must enable
the IRF link failure detection and
auto-recovery.
CAUTION:
After an IRF fabric is set up, you can
modify the IRF port, member ID, and
member priority settings for a member
device, but must make sure you fully
understand the impact on the live
network. For example, a member ID
change can void member ID-related
settings, a priority change might cause
master re-election, and a reconfiguration
of IRF port settings or bindings might
cause an IRF split or merge.
9. (Optional.) Fast-restoring IRF configuration for a
one-MPU member
This task helps you fast-restore IRF
configuration for one-MPU members
before an MPU replacement.
Planning the IRF fabric setup
Consider the following items when you plan an IRF fabric:
•Hardware compatibility and restrictions
•IRF fabric size
•Master device
•IRF physical ports

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•Member ID and priority assignment scheme
•Fabric topology and cabling scheme
For more information about hardware and cabling, see the installation guide for the device.
Preconfiguring IRF member devices in standalone
mode
Perform the tasks in this section on every IRF member device. These settings take effect on each
member device after their operating mode changes to IRF.
Assigning a member ID to each IRF member device
A device by default operates in standalone mode without an IRF member ID. You must assign it a
unique IRF member ID before changing its operating mode to IRF.
Execute the display irf configuration command and examine the MemberID field. If the device has
no IRF member ID, the field displays two hyphens (--).
The member ID assigned to a device is saved in both active and standby MPUs of the device. If the
standby MPU has a different member ID than the active MPU, for example, because of an MPU
replacement, the member ID in the active MPU takes effect and is automatically updated to the
standby MPU.
To set a member ID for the device in standalone mode:
Step Command Remarks
1. Enter system view. system-view N/A
2. Assign an IRF member ID
to the device. irf member member-id By default, the device has no
IRF member ID.
Specifying a priority for each member device
IRF member priority represents the possibility for a device to be elected the master in an IRF fabric.
The higher the priority, the higher the possibility.
To specify a priority for the device in standalone mode:
Step Command Remarks
1. Enter system view. system-view N/A
2. Specify a priority for the
device. irf priority priority The default IRF member
priority is 1.
Binding physical ports to IRF ports
To establish an IRF connection between two devices, you must bind at least one physical port to
IRF-port 1 on one device and to IRF-port 2 on the other. For link redundancy and load sharing, bind
at least two physical ports to one IRF port.