IRF:- IRF stands for Intelligent Redundant Framework. It is similar technology like cisco uses in 6500 series product named as VSS (Virtual Switching System) or Juniper QFabric. Intelligent Resilient Framework (IRF) is an advanced technology that allows  to aggregate 2 or more switches into a single switching and routing system also known as a “virtual switch”. IRF virtualization technology offers processing power, interaction, unified management and uninterrupted maintenance of multiple switches.

IRF delivers the following benefits:-
• Simplified topology and streamlined management. An IRF fabric appears as one node on the
network. We can log in at any member switch to manage all members of the IRF fabric.
• High availability and reliability. The member switches in an IRF fabric work in 1:N redundancy.
One member switch works as the master to manage and maintain the entire IRF fabric, and all other member switches process services and provide backup. If the master fails, all other member switches elect a new master among them to prevent service interruption. We can perform link aggregation not only for IRF links but also for physical links between the IRF fabric and its upper or
lower layer devices for link redundancy.
• Network scalability and resiliency. We can increase ports, network bandwidth, and processing capability of an IRF fabric simply by adding member switches.

Basic concepts of IRF:-

  • IRF member switch roles

IRF uses two member switch roles: master and slave.
When switches form an IRF fabric, they elect a master to manage the IRF fabric, and all other switches back up the master. When the master switch fails, the other switches automatically elect a new master from among them to avoid service interruption.

  • IRF port

An IRF port is a logical interface for the internal connection between IRF member switches. Each IRF member switch has two IRF ports: IRF-port 1 and IRF-port 2. An IRF port is activated when we bind a physical port to it.

  • Physical IRF port

Physical IRF ports are physical ports bound to an IRF port. They connect IRF member switches and forward IRF protocol packets and data packets between IRF member switches. We can configure a GE Ethernet port or a GE SFP port as a physical IRF port.

  • IRF partition

IRF partition occurs when an IRF fabric splits into two or more IRF fabrics because of IRF link failures, as shown in Figure below. The partitioned IRF fabrics operate with the same IP address and cause routing and forwarding problems on the network.

  • IRF merge

IRF merge occurs when two partitioned IRF fabrics re-unite or when you configure and connect two independent IRF fabrics to be one IRF fabric, as shown in Figure below.

  • Member priority

Member priority determines the role that a member switch during the master election process. A member with a higher priority is more likely to be a master.
The priority of a switch defaults to 1. We can modify the priority at the command line interface (CLI).

 
IRF Virtual Device Configuration Procedure List
We will configure IRF in below flowchart fashion as recommended by HP.

Hardware Used :-
(Switch) 2 x JG236A HP 5120-24G-POE+ EI SWITCH W/2 INTF SLTS

(Module) 2 x JD360B HP 5500 2-port 10GbE Loc Connect Module

(Cable) 2 x JD363B HP X230 Local Connect 50cm CX4 Cable

Below IRF Configuration for HP A series Stackable switches (A5120/5500/5800/5820)
  • Login onto the switch using the console port
  • <H3C>system-view (Enter system view aka config mode)
  • [H3C]show version (Ensure that both switches are running the same software version)
  • [H3C]reset saved-configuration (Reset the config)
  • [H3C]irf member 1 renumber 1 (Assign an IRF member number to the first switch)
  • [H3C]irf member 1 renumber 2 (Assign an IRF member number to the second switch)
  • [H3C]quit (Quit to user view)
  • <H3C>save (Save the config)
  • <H3C>reboot (Reboot the switches)
  • <H3C>system-view (Enter system view aka config mode)
  • [H3C]irf mac-address persistent always (Enable MAC address persistance)
  • [H3C]irf member 1 priority 32 (Set the highest priority on the first member/switch aka Master)
  • [H3C]irf member 2 priority 30 (Set the second highest priority on the second member/switch aka Slave)
  • [H3C]int GigabitEthernet 1/0/51
  • shut
  • [H3C]int GigabitEthernet 1/0/52
  • shut
  • [H3C]int GigabitEhternet 2/0/51
  • shut
  • [H3C]int GigabitEthernet 2/0/52
  • shut (shutdown all interfaces you want to use for IRF on both switches)
  • [H3C]irf port 1/1 (Create IRF port 1/1 on the first member)
  • [H3C]port group interface GigabitEthernet 1/0/51 (add the switch port to the IRF port)
  • [H3C]quit
  • [H3C]irf port 1/2 (Create IRF port 1/2 on the first member)
  • [H3C]port group interface GigabitEthernet 1/0/52 (add the switch port to the IRF port)
  • [H3C]quit
  • [H3C]irf port 2/1 (Create IRF port 2/1 on the second member)
  • [H3C]port group interface GigabitEthernet 2/0/51 (add the switch port to the IRF port)
  • [H3C]quit
  • [H3C]irf port 2/2 (Create IRF port 2/2 on the second member)
  • [H3C]port group interface GigabitEthernet 2/0/52 (add the switch port to the IRF port)
  • [H3C]quit
  • [H3C]save (Save config)
  • [H3C]interface GigabitEthernet 1/0/51
  • [H3C]undo shut
  • interface GigabitEthernet 1/0/52
  • [H3C]undo shut
  • [H3C]interface GigabitEthernet 2/0/51
  • [H3C]undo shut
  • [H3C]interface GigabitEthernet 2/0/52
  • [H3C]undo shut (enable all interfaces you want to use for IRF on both switches)
  • [H3C]irf-port-configuration active (Activate the IRF config on BOTH switches)
  • Now we connect our fiber CROSSWISE, so 1/0/51 to 2/0/52 and 1/0/52 to 2/0/51
  • ATTENTION: The second IRF member will reboot! Wait for it to get back up. We will see the switches negotiate for about 30 seconds before the IRF becomes active.
  • If all works well;
  • [H3C]quit
  • <H3C>save
  • <H3C>reboot
  • <H3C>system-view
  • [H3C]display irf (Display the IRF setup)
  • [H3C]display irf topology (Display the IRF Topology)
  • [H3C]display irf configuration
  • [H3C]display devices
  • Both irf port should be up. If one is DOWN or DIS(abled), something went wrong.
  • Check the IRF priority of the First member. It should be 32.
  • Check the IRF priority of the second member. It should be 30.

In the last i want to mention limitations of IRF:-

  • Only devices of the same series can form an IRF :- Same like other Vendors Cisco or Juniper.
  • The devices would have same software code running else they will not form IRF.
  • One device in the IRF is the master, others are slaves. No load distribution or Active/Active scenario. Same as Cisco’s VSS.
  • Numerous stackable switches can form an IRF.
  • IRF partition is detected through proprietarily modified LACP or BFD. Same as Cisco’s VSS.