LevelOne GTL-2691 - Manual (Page 735)

C HAPTER 21 | Multicast Routing
Configuring PIMv6 for IPv6
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C ONFIGURING G LOBAL
PIM6-SM S ETTINGS
Use the Routing Protocol > PIM6 > PIM6-SM (Configure Global) page to
configure the rate at which register messages are sent, the source of
register messages, and switchover to the Shortest Path Tree (SPT).
CLI R EFERENCES
◆ "IPv6 PIM Commands" on page 1575
P ARAMETERS
These parameters are displayed:
◆ Register Rate Limit – Configures the rate at which register messages
are sent by the Designated Router (DR) for each (source, group) entry.
(Range: 1-65535 packets per second: Default: disabled)
This parameter can be used to relieve the load on the designated router
(DR) and rendezvous point (RP). However, because register messages
exceeding the limit are dropped, some receivers may experience data
packet loss within the first few seconds in which register messages are
sent from bursty sources.
◆ Register Source – Configures the IP source address of a register
message to an address other than the outgoing interface address of the
DR that leads back toward the RP. (Range: VLAN 1-4094; Default: The
IP address of the DR’s outgoing interface that leads back to the RP)
When the source address of a register message is filtered by
intermediate network devices, or is not a uniquely routed address to
which the RP can send packets, the replies sent from the RP to the
source address will fail to reach the DR, resulting in PIM6-SM protocol
failures. This type of problem can be overcome by manually configuring
the source address of register messages to an interface that leads back
to the RP.
◆ SPT Threshold – Prevents the last-hop PIM-SM router from switching
to Shortest Path Source Tree (SPT) mode. (Options: Infinity, Reset;
Default: Reset)
The default path for packets from a multicast source to a receiver is
through the RP. However, the path through the RP is not always the
shortest path. Therefore, the router uses the RP to forward only the
first packet from a new multicast group to its receivers. Afterwards, it
calculates the shortest path tree (SPT) directly between the receiver
and source, and then uses the SPT to send all subsequent packets from
the source to the receiver instead of using the shared tree. Note that
when the SPT threshold is not set by this command, the PIM leaf router
will join the shortest path tree immediately after receiving the first
packet from a new source.
Enable the SPT threshold to force the router to use the shared tree for
all multicast groups, or just for the specified multicast groups.
◆ Group Address – An IPv6 multicast group address. If a group address
is not specified, the shared tree is used for all multicast groups.
◆ Group Prefix Length – An IPv6 network prefix length for a multicast
group. (Range: 8-128)