Protocol Independent Multicast (PIM)
PIM is a special signaling protocol that does not distribute any routing information on its own. Rather, PIM uses the unicast routing table to perform RPF checks.When the router receives a multicast packet, it looks at the source IP address for the packet. The router looks up the source IP address in the unicast routing table and determines the outgoing interface for this packet. If this outgoing interface does not match the interface where the packet was received, the router drops the packet. This behavior intends to eliminate potential packet loops, which may occur when routers flood multicast packets. Only the immediate upstream router is allowed to send us multicast packets.
224.0.0.13
Protocol No 103
hellos 30 sec hold 90 sec
Join-Prune-Assert-Graft/Ack-State Refresh
End Machine---->Membership report----->Router---->Join
Assert :- selection who is going to send multicast packets
1.AD/Metric
2.Highest IP
Flood:- every 3min the selection process will happen again for every group
Prune:- When router doesn't have any multicast receiver, timeout 3min
Graft:- group earlier pruned, now traffic is required, in response ack is sent
State Refresh:- 0-100 sec maintains the state of Assert and Prune, Prune flag set to 1(Prune now), keepalive for the pruning, aak the downstream routers do you want this group to be still pruned, if the answer is yes then the periodic flooding doesn't occur
OIL:- Outgoing interface list
Dense Mode
In PIM dense mode Router will initially flood multicast packet across network. This process will help in creation of (S, G) entry in all routers. This process is repeated every three minutes in PIM dense mode. In this process those routers which don’t need the multicast stream that router will prune back the traffic flow. Does not use any explicit signaling
to join a multicast distribution tree. Instead, it uses the inverse logic approach. All routers initially flood packets out of all their multicast-enabled interfaces.PIM Dense mode is also known as PUSH MODE.
(*,G)
(S,G)
Sparse Mode
PIM sparse mode is having a central point of contact for all Multicast host routers. As the Routers will receive the request from host to join particular multicast group, They will check the multicast routing table which is received from PIM and in case of the router is not aware, The request will be forwarded to RP (Rendezvous Point). RP is a designated router in network selected by network administrator as per requirement/Topology. This router will be responsible for providing information about every multicast group to host. All multicast source will register with RP. RP will aware about all multicast group and how to reach to multicast source.
IGMP:
Internet group Membership protocol
Protocol no-2
TTL-1
Query-see if members still in group
Report-Join the group
Querier election
group specific query
Explicit leave
IGMPv1/v2: group specific join (*,G)
IGMPv3: source specific join(S,G) uses always SPT
R1#
ip multicast-routing
!
interface Loopback0
ip address 1.1.1.1 255.255.255.0
!
interface FastEthernet0/0
ip address 12.1.1.1 255.255.255.0
ip pim dense-mode
duplex auto
speed auto
!
interface FastEthernet0/1
ip address 13.1.1.1 255.255.255.0
ip pim dense-mode
duplex auto
speed auto
R7(config)#int f0/0
R7(config-if)#ip igmp join-group 224.10.10.10
The RP of 0.0.0.0 confirms that no RP is used for this group, so we are using PIM dense mode
Confirm again the multicast table on R4
PIM is a special signaling protocol that does not distribute any routing information on its own. Rather, PIM uses the unicast routing table to perform RPF checks.When the router receives a multicast packet, it looks at the source IP address for the packet. The router looks up the source IP address in the unicast routing table and determines the outgoing interface for this packet. If this outgoing interface does not match the interface where the packet was received, the router drops the packet. This behavior intends to eliminate potential packet loops, which may occur when routers flood multicast packets. Only the immediate upstream router is allowed to send us multicast packets.
224.0.0.13
Protocol No 103
hellos 30 sec hold 90 sec
Join-Prune-Assert-Graft/Ack-State Refresh
End Machine---->Membership report----->Router---->Join
Assert :- selection who is going to send multicast packets
1.AD/Metric
2.Highest IP
Flood:- every 3min the selection process will happen again for every group
Prune:- When router doesn't have any multicast receiver, timeout 3min
Graft:- group earlier pruned, now traffic is required, in response ack is sent
State Refresh:- 0-100 sec maintains the state of Assert and Prune, Prune flag set to 1(Prune now), keepalive for the pruning, aak the downstream routers do you want this group to be still pruned, if the answer is yes then the periodic flooding doesn't occur
OIL:- Outgoing interface list
Dense Mode
In PIM dense mode Router will initially flood multicast packet across network. This process will help in creation of (S, G) entry in all routers. This process is repeated every three minutes in PIM dense mode. In this process those routers which don’t need the multicast stream that router will prune back the traffic flow. Does not use any explicit signaling
to join a multicast distribution tree. Instead, it uses the inverse logic approach. All routers initially flood packets out of all their multicast-enabled interfaces.PIM Dense mode is also known as PUSH MODE.
(*,G)
(S,G)
Sparse Mode
PIM sparse mode is having a central point of contact for all Multicast host routers. As the Routers will receive the request from host to join particular multicast group, They will check the multicast routing table which is received from PIM and in case of the router is not aware, The request will be forwarded to RP (Rendezvous Point). RP is a designated router in network selected by network administrator as per requirement/Topology. This router will be responsible for providing information about every multicast group to host. All multicast source will register with RP. RP will aware about all multicast group and how to reach to multicast source.
IGMP:
Internet group Membership protocol
Protocol no-2
TTL-1
Query-see if members still in group
Report-Join the group
Querier election
group specific query
Explicit leave
IGMPv1/v2: group specific join (*,G)
IGMPv3: source specific join(S,G) uses always SPT
R1#
ip multicast-routing
!
interface Loopback0
ip address 1.1.1.1 255.255.255.0
!
interface FastEthernet0/0
ip address 12.1.1.1 255.255.255.0
ip pim dense-mode
duplex auto
speed auto
!
interface FastEthernet0/1
ip address 13.1.1.1 255.255.255.0
ip pim dense-mode
duplex auto
speed auto
R7(config)#int f0/0
R7(config-if)#ip igmp join-group 224.10.10.10
The RP of 0.0.0.0 confirms that no RP is used for this group, so we are using PIM dense mode
Confirm again the multicast table on R4
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