HP 4800G Series Configuration Manual page 824

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Table 1-1 Values in the hashing algorithm

RPT establishment

Figure 1-5 RPT establishment in a PIM-SM domain

1-5, the process of building an RPT is as follows:

When a receiver joins multicast group G, it uses an IGMP message to inform the directly connected

Upon getting the receiver information, the DR sends a join message, which is hop by hop

forwarded to the RP corresponding to the multicast group.

The routers along the path from the DR to the RP form an RPT branch. Each router on this branch

generates a (*, G) entry in its forwarding table. The * means any multicast source. The RP is the

root, while the DRs are the leaves, of the RPT.

The multicast data addressed to the multicast group G flows through the RP, reaches the corresponding

DR along the established RPT, and finally is delivered to the receiver.

When a receiver is no longer interested in the multicast data addressed to multicast group G, the directly

connected DR sends a prune message, which goes hop by hop along the RPT to the RP. Upon

receiving the prune message, the upstream node deletes the interface connected with this downstream

node from the outgoing interface list and checks whether it itself has receivers for that multicast group.

If not, the router continues to forward the prune message to its upstream router.

IP address of the multicast group

Hash mask length

IP address of the C-RP

Logical operator of "and"

Logical operator of "exclusive-or"

Modulo operator, which gives the remainder of an integer division

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