Modifying IPv6 PIM Options

Many IPv6 PIM options can be modified from their default values in IPv6 PIM router configuration mode.

IPv6 PIM parameters come with preset values. The defaults work well in most networks, but you can modify the following parameters if necessary:

  • Neighbor timeout—Neighbor timeout is the interval after which an IPv6 PIM router will consider a neighbor to be absent. If the timer expires before receiving a new hello message, the IPv6 PIM router will time out the neighbor.
  • Hello timer——The hello timer defines the interval at which periodic hellos are sent out IPv6 PIM interfaces. Devices use hello messages to inform neighboring devices of their presence.
  • Join and Prune message timer—By default, an IPv6 PIM device sends IPv6 PIM Sparse Join or Prune messages every 60 seconds. These messages inform other IPv6 PIM Sparse routers about clients who want to become receivers (Join) or stop being receivers (Prune) for IPv6 PIM Sparse groups.
  • Prune wait timer—The prune wait timer allows you to set the amount of time the IPv6 PIM router should wait for a join override before pruning an Outgoing Interface List Optimization (OIF) from the entry and this stops traffic to neighbor devices that do not want the traffic. A prune wait value of zero causes the IPv6 PIM device to stop traffic immediately upon receiving a prune message. If there are two or more neighbors on the physical port, then the prune wait timer must not be used because one neighbor may send a prune message while the other sends a join message at the same time, or within less than three seconds.
  • Shortest Path Tree threshold—To optimize IPv6 PIM traffic, the protocol contains a mechanism for calculating the Shortest Path Tree (SPT) between a given source and a receiver. You can configure a threshold of the number of packets the device receives using the RP before switching to using the SPT.
  • Inactivity timer—The device deletes a forwarding entry if the entry is not used to send multicast packets. The IPv6 PIM inactivity timer defines how long a forwarding entry can remain unused before the device deletes it.
  • Register suppress interval—The amount of time the IPv6 PIM router uses to periodically trigger the NULL register message.
  • Register probe time—The amount of time the IPv6 PIM router waits for a register-stop from an RP before it generates another NULL register to the IPv6 PIM RP. The register probe time configuration applies only to the first hop IPv6 PIM router.
  1. Enter global configuration mode.
    device# configure terminal
  2. Enable IPv6 PIM globally and enter IPv6 PIM router configuration mode.
    device(config)# ipv6 router pim
  3. Apply an IPv6 PIM neighbor timeout value of 50 seconds to all ports on the router operating with IPv6 PIM.
    device(config-ipv6-pim-router)# nbr-timeout 50
    The timeout interval can be set from 35 through 65535 seconds, and it must not be less than 3.5 times the hello timer value. The default value is 105.
  4. Apply a IPv6 PIM hello timer of 62 seconds to all ports on the device operating with IPv6 PIM.
    device(config-ipv6-pim-router)# hello-timer 62
    The hello timer interval can be set from 10 through 3600 seconds, and the default is 30.
  5. Set the Join or Prune message interval to 30 seconds.
    device(config-ipv6-pim-router)# message-interval 30
    The Join or Prune interval timer range is from 10 through 18724 seconds. The default is 180.
    Note: Use the same Join or Prune message interval on all the IPv6 PIM Sparse routers in the IPv6 PIM Sparse domain. If the routers do not all use the same timer interval, the performance of IPv6 PIM Sparse can be adversely affected.
  6. Set the prune wait time to 2 seconds.
    device(config-ipv6-pim-router)# prune-wait 2
    The prune wait value can be set from 0 through 30 seconds. A smaller prune wait value reduces flooding of unwanted traffic. The default is 3. To view the currently configured prune wait time, enter the show ipv6 pim dense command
  7. Change the number of packets the device receives using the RP before switching to the SPT.
    device(config-ipv6-pim-router)# spt-threshold 1000
    In this example, the device does not switch over to using the SPT until it has sent 1000 packets using the RP.
  8. Apply an IPv6 PIM inactivity timer of 160 seconds to all IPv6 PIM interfaces.
    device(config-ipv6-pim-router)# inactivity-timer 160
    The value of the inactivity timer can be set from 60 through 3600 seconds. The default is 180.
    Note: The inactivity timer configured may expire with a delay of 0 to 60 seconds.
  9. Change the default register suppress time to 90 seconds.
    device(config-ipv6-pim-router)# register-suppress-time 90
    The register suppress time has a valid range from 60 through 120 seconds. The default is 60.
    Note: The register suppress time configuration applies only to the first hop IPv6 PIM router.
  10. Change the default register probe time to 20 seconds.
    device(config-ipv6-pim-router)# register-probe-time 20
    The value of the register probe can be set from 10 through 360050 seconds. The default is 10.
    Note: Once an IPv6 PIM first hop router successfully registers with a IPv6 PIM RP, the IPv6 PIM first hop router will not default back to the data registration. All subsequent registers will be in the form of the NULL registration.

The following example shows how to configure the various IPv6 PIM options.

device# configure terminal
device(config)# ipv6 router pim
device(config-ipv6-pim-router)# nbr-timeout 50
device(config-ipv6-pim-router)# hello-timer 62
device(config-ipv6-pim-router)# message-interval 30
device(config-ipv6-pim-router)# prune-wait 2
device(config-ipv6-pim-router)# spt-threshold 1000
device(config-ipv6-pim-router)# inactivity-timer 160
device(config-ipv6-pim-router)# register-suppress-time 90
device(config-ipv6-pim-router)# register-probe-time 20