Инструкции По Установке для 3com S7906E

 

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The purpose of IPv6 multicast source registration is to inform the RP about the existence of the IPv6 

multicast source. 

Figure 1-6 IPv6 multicast source registration 

Server

Host A

Host B

Host C

IPv6 multicast packets

SPT

Join message

Register message

 

 

As shown in 

, the IPv6 multicast source registers with the RP as follows:  

1)  When the IPv6 multicast source S sends the first IPv6 multicast packet to IPv6 multicast group G, 

the DR directly connected with the multicast source, upon receiving the multicast packet, 

encapsulates the packet in a register message, and sends the message to the corresponding RP 

by unicast.  

2)  When the RP receives the register message, it extracts the multicast packet from the register 

message and forwards the multicast IPv6 multicast packet down the RPT, and sends an (S, G) join 

message hop by hop toward the IPv6 multicast source. Thus, the routers along the path from the 

RP to the IPv6 multicast source form an SPT branch. Each router on this branch generates an (S, 

G) entry in its forwarding table. The DR at the IPv6 multicast source side is the root, while the RP is 

the leaf, of the SPT. 

3)  The subsequent IPv6 multicast data from the IPv6 multicast source travels along the established 

SPT to the RP, and then the RP forwards the data along the RPT to the receivers. When the IPv6 

multicast traffic arrives at the RP along the SPT, the RP sends a register-stop message to the 

source-side DR by unicast to stop the source registration process.  

 

The RP is configured to initiate an SPT switchover as described in this section. Otherwise, the DR at the 

IPv6 multicast source side keeps encapsulating multicast data in register messages and the registration 

process will not stop unless no outgoing interfaces exist in the (S, G) entry on the RP.