Multicast - Implementing Multicast (MCAST V1.0) - PIM SM (5)

- RFC 2362

- explicit join behavior

* Receivers join RP

* Source regsiter with RP

- RPF Check

* shortest tree uses RP address

* Source tree uses multicast source address

- one RP for a group

- RP statically configured or dynamic (AutoRP, PIMv2 BSR)


PIM-SM Sender Registration

- first-hop-source-router register (with unicast) with RP

- RP sends joins to the source to build SPT from source to RP

- when RP receiving multicast traffic from the source it sends a PIM register-stop message to the firt-hop-source-router



PIM SM SPT Switchover

- PIM has the capability to bypass RP when traffic rate is above configured threshold (default 0)



PIM SM v2 packets

- PIM Hello / PIM Query in PIMv1

- PIM Join / Prune (prunes used to cut off traffic)

- PIM Register / Register Stop

- Rendevouz Point announcement

* Bootstrap mechanism PIM Boostrap and Candidate-RP-advertisement

* Auto-RP mechanism, cisco-announce and Cisco-Discovery /Cisco addition to PIMv1)

* RP-reachability (Cisco-specific)



PIM Neighbor Discovery

- 224.0.0.13 - PIMv2 Hellos every 30 sec

- 224.0.0.2 - PIMv1 Queries

- DR election, responsible for join, register on multiaccess networks
- PIM State

* used to make multicast traffic forwarding decision

* (*,G) and (S,G) entries

- each entry contains RPF infos

- each entry contains OIL (outgoing interface list



PIM SM State Rules

- (*,G) creation - receipt of a join or IGMP report, reflects default group forwarding, deletion when OIL = nll and no (S,G) exists

- (S,G) creation - by receipt of (S,G) join or Prune, by receipt of traffic from directyl connected, OIL=copy of (*,G) minus IIF, deletion by timeout)



PIM SM State Flags

- S=Sparse Mode, C=directly connected Host, L=Local Router, P=Pruned (all interfaces in OIL=pruned), T=Forwarding in SPT, J=Join SPT (if SPT-Threshold exceeded),F=Register,R=RP bit



PIM SM Joining

- senders begin sourcing multicast traffic

- first-hop-router unicasts register to RP

- RP sends (S,G) join toward source/first hop router



PIM SM Configuration

Enabling Multicast-Routing

Router1(config)#ip multicast-routing 

Enabling Sparse-Mode on Interface | Sparse-Dense-Mode (mixed)

Router1(config-if)#ip pim sparse-mode | ip pim sparse-dense-mode

Threshold for SPT Switchover

Router1(config)#ip pim spt-threshold 200 group-list 1

Never switchover to SPT

Router1(config)#ip pim spt-threshold infinity 

Set Rendevouz Point (RP) (override = override dynamic learned RP)

Router1(config)#ip pim rp-address 3.3.3.3 [override]

Show RPs and Group-to-RP-Mappings

Router1#show ip pim rp
Group: 239.0.0.1, RP: 3.3.3.3, next RP-reachable in 00:00:13
Group: 224.0.1.40, RP: 3.3.3.3, next RP-reachable in 00:00:13
Router1#show ip pim rp map
Router1#show ip pim rp mapping 
PIM Group-to-RP Mappings

Acl: 3, Static
    RP: 150.1.3.3 (?)
Acl: 4, Static
    RP: 150.1.4.4 (?)
Group(s): 224.0.0.0/4, Static-Override
    RP: 3.3.3.3 (?)
Router1#

Show all PIM neighbors

Router1#show ip pim neighbor 
PIM Neighbor Table
Neighbor          Interface                Uptime/Expires    Ver   DR
Address                                                            Prio/Mode
10.0.0.2          FastEthernet0/13         00:01:32/00:01:40 v2    1 / DR S
Router1#

Show all PIM-configured interfaces

Router1#show ip pim interface       

Address          Interface                Ver/   Nbr    Query  DR     DR
                                          Mode   Count  Intvl  Prior
3.3.3.3          Loopback0                v2/S   0      30     1      3.3.3.3
10.0.0.1         FastEthernet0/13         v2/S   1      30     1      10.0.0.2
Router1#

Debugging see PIM-DM-Blog-entry....