Users Guide

The following figure shows the anycast IP-based gateway configuration for a VLAN:
The ip virtual-router address and ipv6 virtual-router address commands assign the specified address as
the virtual IPv4 or IPv6 address for the VLAN interface, respectively. Before assigning the anycast IP address to a VLAN
interface, configure a virtual MAC address to the switch using the ip virtual-router mac-address command. All virtual
addresses on all VLAN interfaces resolve to the configured virtual MAC address.
This feature supports only Active-Active mode of data plane forwarding. That means, the traffic is processed by any switch that
is configured with a virtual gateway address. As the requests come into a single IP address associated with the anycast network,
the network distributes the data among the switches based on best route in the routing table. Anycast IP gateway routing is
able to route incoming connection requests across multiple data centers.
Deployment considerations
● Anycast IP gateway feature works only when VLT configurations are present in the switch. If you enable this feature without
VLT domain configuration, the anycast IP gateway configuration remains inactive.
● For anycast IP to work in VLT domain, configure the same anycast IPv4 or IPv6 address and same global virtual MAC
address on both VLT nodes.
● When you use VRRP MAC as an anycast gateway MAC, do not use the underlying VRRP group ID in VLANs or interfaces
where you configured VRRP. Use a non-VRRP MAC as the anycast gateway MAC to avoid such conflicts.
● Anycast IP gateway routing and VRRP are mutually exclusive. You cannot configure both simultaneously on VLANs.
● You can enable the anycast IP gateway for up to 512 Layer 3 (L3) VLANs.
Layer 2
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