LevelOne GTL-2691 User Manual

Page 1578

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C

HAPTER

50

| Multicast Routing Commands

PIM Multicast Routing

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globally for the router with the

router pim6

command, and also enable

PIM-DM or PIM-SM for each interface that will participate in multicast

routing with this command.

If you enable PIM on an interface, you should also enable MLD (see

"MLD (Layer 3)" on page 1273

) on that interface. PIM mode selection

determines how the switch populates the multicast routing table, and

how it forwards packets received from directly connected LAN

interfaces. Dense mode interfaces are always added to the multicast

routing table. Sparse mode interfaces are added only when periodic

join messages are received from downstream routers, or a group

member is directly connected to the interface.

Dense-mode interfaces are subject to multicast flooding by default, and

are only removed from the multicast routing table when the router

determines that there are no group members or downstream routers,

or when a prune message is received from a downstream router.

Sparse-mode interfaces forward multicast traffic only if a join message

is received from a downstream router or if group members are directly

connected to the interface. When routers want to receive a multicast

flow, they periodically send join messages to the Rendezvous Point

(RP), and are subsequently added to the shared path for the specified

flow back up to the RP. If routers want to join the source path up

through the Shortest Path Source Tree (SPT), they periodically send

join messages toward the source. They also send prune messages

toward the RP to prune the shared path if they have already connected

to the source through the SPT, or if there are no longer any group

members connected to the interface.

E

XAMPLE

Console(config)#interface vlan 1

Console(config-if)#ipv6 pim dense-mode

Console(config-if)#end

Console#show ipv6 pim interface

PIM is enabled.

VLAN 1 is up.

PIM Mode : Dense Mode

IPv6 Address : None

Hello Interval : 30 sec

Hello HoldTime : 105 sec

Triggered Hello Delay : 5 sec

Join/Prune Holdtime : 210 sec

Lan Prune Delay : Disabled

Propagation Delay : 500 ms

Override Interval : 2500 ms

Graft Retry Interval : 3 sec

Max Graft Retries : 3

State Refresh Ori Int : 60 sec

Console#

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