active-active

Syntax

active-active

Description

This command enables the PIM active-active mechanism per VRF on VSX. The default is disabled.

The no form of this command disables the PIM active-active mechanism.

Command context

config-pim

Authority

Administrators

Usage

This command keeps the multicast forwarding state synchronized on both VSX peer devices. Synchronization is achieved by electing the VSX peer that has the highest IP address as a designated router (DR) and the other as Proxy-DR.

If the user wants the multicast traffic to flow through VSX primary, assign higher IP addresses to the interfaces in VSX primary. When the VSX peer that is acting as the DR goes down, traffic is recovered faster since the multicast routes are synchronized.

Recommendations:

  • Do not configure the DR priority of interfaces when active-active is enabled. The DR priority will be set to high on DR and default on Proxy-DR and any user-configured DR priority will be ignored.

  • Always configure keepalive between VSX peers. If the ISL goes down when keepalive is not configured, both VSX peers start acting independently as DRs, resulting in duplicate traffic.

  • Do not have IGMP joins on transit VLANS.

  • RP redundancy is not supported on the active-active feature. If one of the VSX peers is configured as RP and it goes down, the new flows will not be converged until the RP is elected. For a static RP, new flows will never be converged until the VSX peer is back up.

  • Do not configure active-active on a non-VSX setup.

Example

Enabling the PIM active-active mechanism: 

switch(config)# router pim
switch(config-pim)# active-active
switch(config-pim)# no active-active

Disabling the PIM active-active mechanism: 

switch(config)# router pim
switch(config-pim)# no active-active