TechLibrary

Navigation
Guide That Contains This Content
[+] Expand All
[-] Collapse All

    Configuring Interface Priority for PIM Designated Router Selection

    A designated router (DR) sends periodic join messages and prune messages toward a group-specific rendezvous point (RP) for each group for which it has active members. When a Protocol Independent Multicast (PIM) routing device learns about a source, it originates a Multicast Source Discovery Protocol (MSDP) source-address message if it is the DR on the upstream interface.

    By default, every PIM interface has an equal probability (priority 1) of being selected as the DR. Configuring the interface DR priority helps ensure that changing an IP address does not alter your forwarding model.

    To configure the interface designated router priority:

    1. This example shows the configuration for the routing instance. Configure the interface globally or in the routing instance.
      [edit routing-instances PIM.master protocols pim interface ge-0/0/0.0 family inet]user@host# set priority 5
    2. Verify the configuration by checking the Hello Option DR Priority field in the output of the show pim neighbors detail command.
      user@host> show pim neighbors detail
      Instance: PIM.master
      Interface: ge-0/0/0.0
      Address: 192.168.195.37, IPv4, PIM v2, Mode: Sparse
      Hello Option Holdtime: 65535 seconds
      Hello Option DR Priority: 5
      Hello Option LAN Prune Delay: delay 500 ms override 2000 ms
      Join Suppression supported
      Rx Join: Group Source Timeout
      225.1.1.1 192.168.195.78 0
      225.1.1.1 0
      
      Interface: lo0.0
      Address: 10.255.245.91, IPv4, PIM v2, Mode: Sparse
      Hello Option Holdtime: 65535 seconds
      Hello Option DR Priority: 1
      Hello Option LAN Prune Delay: delay 500 ms override 2000 ms
      Join Suppression supported
      
      Interface: pd-6/0/0.32768
      Address: 0.0.0.0, IPv4, PIM v2, Mode: Sparse
      Hello Option Holdtime: 65535 seconds
      Hello Option DR Priority: 0
      Hello Option LAN Prune Delay: delay 500 ms override 2000 ms
      Join Suppression supported

    Modified: 2015-07-31