• You can reduce the number of VLTi port channel members based on your specific design.With peer routing, you need not configure VRRP for the participating VLANs. As both VLT nodes act as a gateway for its peer, irrespectiveof the gateway IP address, the traffic flows upstream without any latency. There is no limitation for the number of VLANS.VLT Unicast RoutingVLT unicast routing is a type of VLT peer routing that locally routes unicast packets destined for the L3 endpoint of the VLT peer. Thismethod avoids sub-optimal routing. Peer-routing syncs the MAC addresses of both VLT peers and requires two local DA entries in TCAM. Ifa VLT node is down, a timer that allows you to configure the amount of time needed for peer recovery provides resiliency. You can enableVLT unicast across multiple configurations using VLT links. You can enable ECMP on VLT nodes using VLT unicast.VLT unicast routing is supported on both IPv4 and IPv6. To enable VLT unicast routing, both VLT peers must be in L3 mode. Static routeand routing protocols such as RIP, OSPF, ISIS, and BGP are supported. However, point-to-point configuration is not supported. To enableVLT unicast, the VLAN configuration must be symmetrical on both peers. You cannot configure the same VLAN as Layer 2 on one nodeand as Layer 3 on the other node. Configuration mismatches are logged in the syslog and display in the show vlt mismatch commandoutput.If you enable VLT unicast routing, the following actions occur:• L3 routing is enabled on any new IP address / IPv6 address configured for a VLAN interface that is up.• L3 routing is enabled on any VLAN with an admin state of up.NOTE: If the CAM is full, do not enable peer-routing.NOTE: The peer routing and peer-routing-timeout is applicable for both IPv6/ IPv4.Configuring VLT UnicastTo enable and configure VLT unicast, follow these steps.1 Enable VLT on a switch, then configure a VLT domain and enter VLT-domain configuration mode.CONFIGURATION modevlt domain domain-id2 Enable peer-routing.VLT DOMAIN modepeer-routing3 Configure the peer-routing timeout.VLT DOMAIN modepeer-routing—timeout valuevalue: Specify a value (in seconds) from 1 to 65535. The default value is infinity (without configuring the timeout).VLT Multicast RoutingVLT multicast routing is a type of VLT peer routing that provides resiliency to multicast routed traffic during the multicast routing protocolconvergence period after a VLT link or VLT peer fails using the least intrusive method (PIM) and does not alter current protocol behavior.Unlike VLT unicast routing, a normal multicast routing protocol does not exchange multicast routes between VLT peers. When you enableVLT multicast routing, the multicast routing table is synced between the VLT peers. Only multicast routes configured with a Spanned VLANIP as their IIF are synced between VLT peers. For multicast routes with a Spanned VLAN IIF, only OIFs configured with a Spanned VLAN IPinterface are synced between VLT peers.Virtual Link Trunking (VLT) 993
