HP 6125G HP 6125G & 6125G/XG Blade Switches IP Multicast Configuration - Page 142

value takes effect. If you want to enable neighbor tracking, be sure to enable the neighbor tracking feature on all PIM routers on a multi-access subnet. The LAN-delay setting will cause the upstream routers to delay processing 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 multicast data, it must send a join message within the prune override interval. Otherwise, the upstream router will perform the prune action when the period of LAN-delay plus override-interval times out. A hello message sent from a 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 a PIM router does not change unless the status of the router changes (for example, when 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 a 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 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 Step 1. Enter system view. 2. Enter PIM view. 3. Configure the priority for DR election. Command system-view pim hello-option dr-priority priority 4. Configure PIM neighbor timeout time. hello-option holdtime interval 5. Configure the prune message delay time (LAN-delay). hello-option lan-delay interval 6. Configure the prune override hello-option override-interval interval. interval 7. Disable join suppression. hello-option neighbor-tracking Configuring hello options on an interface Remarks N/A N/A Optional. 1 by default. Optional. 105 seconds by default. Optional. 500 milliseconds by default. Optional. 2500 milliseconds by default. Enabled by default. Step 1. Enter system view. 2. Enter interface view. 3. Configure the priority for DR election. Command Remarks system-view N/A interface interface-type interface-number N/A Optional. pim hello-option dr-priority priority 1 by default. 131