Configuring PIMv6-DM

Function Introduction

The Ipv6 Protocol Independent Multicasting-Dense Mode (PIMv6-DM) is a multicast routing protocol designed to operate efficiently across Wide Area Networks (WANs) with densely distributed groups. It helps network nodes that are geographically dispersed to conserve bandwidth, and reduces traffic by simultaneously delivering a single stream of information to multiple locations.

PIMv6-DM assumes that when a source starts sending, all down stream systems want to receive multicast datagrams. Initially, multicast datagrams are flooded to all areas of the network. PIMv6-DM uses RPF to prevent looping of multicast datagrams while flooding. If some areas of the network do not have group members, PIMv6-DM will prune off the forwarding branch by instantiating prune state.

Prune state has a finite lifetime. When that lifetime expires, data will again be forwarded down the previously pruned branch. Prune state is associated with an (S,G) pair. When a new member for a group G appears in a pruned area, a router can “graft” toward the source S for the group, thereby turning the pruned branch back into a forwarding branch.

Principle Description

The PIMv6-DM module is based on the following IETF standard: RFC 3973

Configuring General PIM dense-mode

PIMv6-DM is a soft-state protocol. The main requirement is to enable PIMv6-DM on desired interfaces. All multicast group states are maintained dynamically as the result of MLD Report/Leave and PIMv6 messages.

3. PIMv6 dense-mode

This section provides PIMv6-DM configuration examples for two relevant scenarios. The following graphic displays the network topology used in these examples: In this example, using the above topology, multicast data stream comes to eth-0-1 of Switch1, host is connected to eth-0-1 of Switch2. Here is a sample configuration:

The following configuration should be operated on all switches if the switch ID is not specified.

Switch(config)# ipv6 enable
Switch(config)# ipv6 multicast-routing

Switch(config)# interface eth-0-1
Switch(config-if)# no shutdown
Switch(config-if)# no switchport
Switch(config-if)# ipv6 address 2001:1::1/64
Switch(config-if)# ipv6 pim dense-mode
Switch(config-if)# exit
Switch(config)# interface eth-0-9
Switch(config-if)# no shutdown
Switch(config-if)# no switchport
Switch(config-if)# ipv6 address 2001:2::1/64
Switch(config-if)# ipv6 pim dense-mode
Switch(config-if)# exit

Switch(config)# interface eth-0-1
Switch(config-if)# no shutdown
Switch(config-if)# no switchport
Switch(config-if)# ipv6 address 2001:3::1/64
Switch(config-if)# ipv6 pim dense-mode
Switch(config-if)# exit
Switch(config)# interface eth-0-9
Switch(config-if)# no shutdown
Switch(config-if)# no switchport
Switch(config-if)# ipv6 address 2001:2::2/64
Switch(config-if)# ipv6 pim dense-mode
Switch(config-if)# exit

Switch# show ipv6 pim dense-mode interface
Neighbor Address Interface VIFIndex Ver/ Nbr
Mode Count
fe80::326f:c9ff:fef2:8200 eth-0-1 0 v2/D 0
fe80::326f:c9ff:fef2:8200 eth-0-9 2 v2/D 1

Switch# show ipv6 pim sparse-mode neighbor
Neighbor Address Interface Uptime/Expires Ver
fe80::ce47:6eff:feb7:1400 eth-0-9 00:51:51/00:01:24 v2

Switch# show ipv6 pim dense-mode mroute
PIM-DM Multicast Routing Table
(2001:1::2, ff0e::1)
Source directly connected on eth-0-1
State-Refresh Originator State: Originator
Upstream IF: eth-0-1
Upstream State: Forwarding
Assert State: NoInfo
Downstream IF List:
eth-0-9, in \'olist\':
Downstream State: NoInfo
Assert State: NoInfo

Switch# show ipv6 pim dense-mode mroute
PIM-DM Multicast Routing Table
(2001:1::2, ff0e::1)
RPF Neighbor: none
Upstream IF: eth-0-9
Upstream State: AckPending
Assert State: Loser
Downstream IF List:
eth-0-1, in \'olist\':
Downstream State: NoInfo
Assert State: NoInfo