HP 6125XLG R2306-HP 6125XLG Blade Switch IP Multicast Configuration Guide - Page 165

Configuring IPv6 PIM hello message options In either an IPv6 PIM-DM domain or an IPv6 PIM-SM domain, hello messages exchanged among routers contain the following configurable options: • DR_Priority (for IPv6 PIM-SM only)-Priority for DR election. The device with the highest priority wins the DR election. You can configure this option for all the routers in a shared-media LAN that directly connects to the IPv6 multicast source or the receivers. • Holdtime-IPv6 PIM neighbor lifetime. If a router receives no hello message from a neighbor when the neighbor lifetime expires, it regards the neighbor failed or unreachable. • LAN_Prune_Delay-Delay of forwarding prune messages on a shared-media LAN. This option consists of LAN delay (namely, prune message delay), override interval, and neighbor tracking support (namely, the capability to disable join message suppression). The prune message delay defines the delay time for a router to forward a received prune message to the upstream routers. The override interval defines a time period for a downstream router to override a prune message. If the prune message delay or override interval on different IPv6 PIM routers on a shared-media LAN are different, the largest value takes effect. A router does not immediately prune an interface after it receives a prune message from the interface. Instead, it starts a timer (the prune message delay plus the override interval). If interface receives a join message before the override interval expires, the router does not prune the interface. Otherwise, the router prunes the interface when the timer (the prune message delay plus the override interval) expires. You can enable the neighbor tracking function (or disable the join message suppression function) on an upstream router to track the states of the downstream nodes that have sent the join message and the joined state holdtime timer has not expired. If you want to enable the neighbor tracking function, you must enable it on all IPv6 PIM routers on a shared-media LAN. Otherwise, the upstream router cannot track join messages from every downstream routers.. • Generation ID-A router generates a generation ID for hello messages when an interface is enabled with IPv6 PIM. The generation ID is a random value, but only changes when the status of the router changes. 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 router has changed. In this case, it sends a join message to the upstream router for status update. You can configure an interface to drop hello messages without the generation ID options to promptly know the status of an upstream router. You can configure hello message options in IPv6 PIM view or interface view. The configurations made in IPv6 PIM view are effective on all interfaces and the configurations made in interface view are effective on only the current interface. If you configure hello message options in both IPv6 PIM view and interface view, the configuration in interface view always takes precedence. Configuring hello message options globally Step 1. Enter system view. 2. Enter IPv6 PIM view. 3. Set the DR priority. 4. Set the neighbor lifetime. Command system-view ipv6 pim hello-option dr-priority priority hello-option holdtime time Remarks N/A N/A By default, the DR priority is 1. By default, the neighbor lifetime is 105 seconds. 158