Dell C1048P Port Extender Networking Configuration Guide for the C9000 Series - Page 352

Weighted ECMP for Static Routes Dell Networking OS also supports Weighted ECMP for static routes. You can configure weights corresponding to the paths for a static destination. If all configured paths have weights, traffic distribution is performed using the Weighted ECMP method with the RTM these passing weights to the FIB. If all configured paths do not have weights, regular ECMP is used to determine traffic paths. Also, paths that are configured with a weight value of 0 are explicitly excluded from Weighted ECMP calculations. The RTM does not inform the FIB about these paths (next-hops). NOTE: Dell Networking OS also supports a global configuration parameter to enable or disable Weighted ECMP for static routes on the system. The following example shows weighted ECMP configuration for Static Routes: Dell(conf)#ip route 1.1.1.0/24 4.4.4.2 weight 100 Dell(conf)#ip route 1.1.1.0/24 6.6.6.2 weight 200 Dell#show running-config | grep route ip route 1.1.1.0/24 4.4.4.2 weight 100 ip route 1.1.1.0/24 6.6.6.2 weight 200 Dell(conf)#ip route vrf test 1.1.1.0/24 4.4.4.2 weight 100 Dell(conf)#ip route vrf test 1.1.1.0/24 6.6.6.2 weight 200 Dell(conf)# Dell(conf)# Dell#show running-config | grep route ip route vrf test 1.1.1.0/24 4.4.4.2 weight 100 ip route vrf test 1.1.1.0/24 6.6.6.2 weight 200 ECMP Support in L3 Host and LPM Tables The L3 host and Longest Prefix Match (LPM) tables provide ECMP next-hop forwarding for destination addresses. You can program IPv6 /128 and IPv4 /32 route prefixes to be stored in the L3 host table and move IPv6 /128 and IPv4 /32 route prefixes between the host table and the LPM route table. By default, IPv4 route prefixes are installed only in the LPM table and IPv6/128 route prefixes are installed only in the L3 host table. In previous releases, the IPv6 /128 entries in the host table were not supported by ECMP. NOTE: When moving destination prefixes from the LPM to the host table, there may be a hash collision because the host table is a hash table. In this case, a workaround does not exist for programming route entries in the host table. NOTE: Before moving IPv6/128 route prefixes from the host table to the LPM table, you must enable LPM CAM partitioning for extended IPv6 prefixes. See Configuring the LPM Table for IPv6 Extended Prefixes for more information. Use the ipv4 unicast-host-route or ipv6 unicast-host-route commands to program IPv4 /32 or IPv6 /128 route prefixes to be stored in the L3 host table. A warning message states that the change takes effect only when IPv4 or IPv6 route prefixes are cleared from the routing table (RTM) using the clear ip route * command. The IPv6 /128 and IPv4 /32 routeprefix entries that you move to the host table receive ECMP handling. To verify ECMP support for IPv6 /128 route prefixes stored in the host table, use the show ipv6 cam command. The command output includes the ECMP field with IPv6 neighbor addresses. 1 indicates ECMP handling of destination routes. Dell# show ipv6 cam linecard 0 port-set 0 Neighbor Mac-Addr Port Vid EC [ 132] 20::1 00:00:20:d5:ec:a0 Fo 0/16 0 1 [ 132] 20::1 00:00:20:d5:ec:a1 Fo 0/24 0 1 To re-enable programming of IPv6 /128 route prefixes in the LPM table, use the no ipv6 unicast-host-route command. A warning message states that the change takes effect only when IPv4 or IPv6 route prefixes are cleared from the routing table (RTM) using the clear ip route * command. Equal Cost Multi-Path (ECMP) 352