HP 6125G HP 6125G & 6125G/XG Blade Switches IP Multicast Configuration - Page 326

Step 1. Enter system view. 2. Enter interface view. 3. Configure a hello message filter. Command system-view interface interface-type interface-number pim ipv6 neighbor-policy acl6-number Remarks N/A N/A No hello message filter by default NOTE: With the hello message filter configured, if hello messages of an existing IPv6 PIM neighbor fail to pass the filter, the IPv6 PIM neighbor will be removed automatically when it times out. Configuring IPv6 PIM hello options In either an IPv6 PIM-DM domain or an IPv6 PIM-SM domain, the hello messages sent among routers contain the following configurable options: • DR_Priority (for IPv6 PIM-SM only)-Priority for DR election. The higher the priority is, the easier it is for the router to win DR election. You can configure this parameter on all the routers in a multi-access network directly connected to IPv6 multicast sources or receivers. • Holdtime-The timeout time of IPv6 PIM neighbor reachability state. When this timer times out, if the router has received no hello message from an IPv6 PIM neighbor, it assumes that this neighbor has expired or become unreachable. • LAN_Prune_Delay-The delay of prune messages on a multi-access network. This option consists of LAN-delay (namely, prune message delay), override-interval, and neighbor tracking flag. If the LAN-delay or override-interval values of different IPv6 PIM routers on a multi-access subnet are different, the largest value takes effect. If you want to enable neighbor tracking, be sure to enable the neighbor tracking feature on all IPv6 PIM routers on a multi-access subnet. The LAN-delay setting will cause the upstream routers to delay forwarding received prune messages. The override-interval sets the length of time that a downstream router can wait before sending a prune override message. When a router receives a prune message from a downstream router, it does not perform the prune action immediately. Instead, it maintains the current forwarding state for a period of LAN-delay plus override-interval. If the downstream router needs to continue receiving IPv6 multicast data, it must send a join message within the prune override interval. Otherwise, the upstream route will perform the prune action when the period of LAN-delay plus override-interval times out. A hello message sent from an IPv6 PIM router contains a generation ID option. The generation ID is a random value for the interface on which the hello message is sent. Normally, the generation ID of an IPv6 PIM router does not change unless the status of the router changes (for example, when IPv6 PIM is just enabled on the interface or the device is restarted). When the router starts or restarts sending hello messages, it generates a new generation ID. If an IPv6 PIM router finds that the generation ID in a hello message from the upstream router has changed, it assumes that the status of the upstream neighbor is lost or that the upstream neighbor has changed. In this case, it triggers a join message for state update. If you disable join suppression (namely, enable neighbor tracking), be sure to disable the join suppression feature on all IPv6 PIM routers on a multi-access subnet. Otherwise, the upstream router will fail to explicitly track join messages from downstream routers. Configuring hello options globally 315