3Com 4800G Series, Configuration Manual

Page: 656 / 1246

656 C
HAPTER
47: PIM C
ONFIGURATION
Configuring hello options on an interface
Follow these steps to configure hello options on an interface:
Configuring PIM
Common Timers
PIM routers discover PIM neighbors and maintain PIM neighboring relationships
with other routers by periodically sending out hello messages.
Upon receiving a hello message, a PIM router waits a random period, which is
equal to or smaller than the maximum delay between hello messages, before
sending out a hello message. This avoids collisions that occur when multiple PIM
routers send hello messages simultaneously.
Any router that has lost assert election will prune its downstream interface and
maintain the assert state for a period of time. When the assert state times out, the
assert losers will resume multicast forwarding.
A PIM router periodically sends join/prune messages to its upstream for state
update. A join/prune message contains the join/prune timeout time. The upstream
router sets a join/prune timeout timer for each pruned downstream interface, and
resumes the forwarding state of the pruned interface when this timer times out.
When a router fails to receive subsequent multicast data from the multicast source
S, the router will not immediately delete the corresponding (S, G) entries; instead,
it maintains (S, G) entries for a period of time, namely the multicast source
lifetime, before deleting the (S, G) entries.
Configuring PIM common timers globally
Follow these steps to configure PIM common timers globally:
To do… Use the command… Remarks
Enter system view system-view -
Enter interface view interface interface-type
interface-number
-
Configure the priority for DR
election pim hello-option dr-priority
priority
Optional
1 by default
Configure PIM neighbor
timeout time pim hello-option holdtime
interval
Optional
105 seconds by default
Configure the prune delay
time (LAN-delay) pim hello-option lan-delay
interval
Optional
500 milliseconds by default
Configure the prune override
interval pim hello-option
override-interval
interval
Optional
2,500 milliseconds by default
Disable join suppression pim hello-option
neighbor-tracking Optional
Enabled by default
Configure the interface to
reject hello messages without
a generation ID pim require-genid Optional
By default, hello messages
without Generation_ID are
accepted
To do… Use the command… Remarks
Enter system view system-view -