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IRB Anycast

This section briefly describes integrated routing and bridging (IRB) feature and its anycast gateway configuration on the QFX5220, QFX5230, QFX5240, and QFX5241 Switches.

Overview

The integrated routing and bridging (IRB) feature enables Layer 2 bridging and Layer 3 IP routing on the same interface, allowing efficient routing between VLANs or bridge domains without a separate router. When specifying an IP or a MAC address for an IRB interface on the multihomed devices, you can use an anycast address. The anycast address enables you to configure the same addresses for the IRB interface on each of the multihomed devices, thereby establishing the devices as anycast gateways.

An IRB anycast gateway uses IRB interfaces on multihomed devices to share the same IP and MAC address as a default gateway, enabling redundancy and load balancing in an EVPN-MPLS, EVPN-VXLAN, or L2VPN setup.

The QFX5220, QFX5230, QFX5240, and QFX5241 switches support IRB on both default routing instances and virtual routing and forwarding (VRF) instances. To segment the traffic on a LAN into separate broadcast domains, separate virtual LANs (VLANs) are created. VLANs limit the amount of traffic flowing across the entire LAN, reducing the possible number of collisions and packet retransmissions within the LAN.

For more information about IRB, see Understanding Integrated Routing and Bridging.

Configure IRB Anycast Gateway

Your IP address subnet scheme helps to determine whether you can use the IRB interface commands to set up your anycast gateway or not. Before you begin the configuration, ensure that:

  1. The router interfaces are configured.

  2. An underlay protocol such as OSPF, ISIS, or BGP is configured.

  3. BGP is configured.

  4. MPLS is configured.

Note: For information about IRB anycast gateway configuration guidelines, see Anycast Gateway Configuration Guidelines and for limitations, see Anycast Gateway Configuration Limitations.

Run the following commands in the CLI at the [edit] hierarchy level.

To configure an IRB interface with an IPv4 or an IPv6 address:

To configure an IRB interface with a media access control (MAC) address:

Note: In the command above, you can also use the MAC address (chassis MAC) that Juniper Networks devices automatically generate.

To configure a virtual gateway address (VGA) with IPv4 and IPv6 address:

To configure a virtual gateway address (VGA) with MAC address:

Note: In these commands, you can also use the MAC address (chassis MAC) that Juniper Networks devices automatically generate.

Verify IRB Anycast Gateway

Run the following sample commands to verify that the IRB anycast gateway feature is configured.

  • To verify that the interface is up and IP is configured properly:

  • To verify that IRB anycast IP address or MAC address is configured properly:

  • To verify that advertised MAC address and IP addresses route is present:

  • To verify leaf routing table is reachable:

  • To verify end-to-end connectivity: