3com S7906E 설치 설명서

 

1-2 

All MLD versions support the Any-Source Multicast (ASM) model. In addition, MLDv2 can be directly 

deployed to implement the Source-Specific Multicast (SSM) model, while MLDv1 needs to work with the 

MLD SSM mapping function to implement SSM service.  

 

For more information about the ASM and SSM models, see Multicast Overview in the IP Multicast 

Volume.  

 

MLDv1 implements IPv6 multicast listener management based on the query/response mechanism. 

Of multiple IPv6 multicast routers on the same subnet, all the routers can hear MLD listener report 

messages (often referred to as reports) from hosts, but only one router is needed for sending MLD 

query messages (often referred to as queries). So, a querier election mechanism is required to 

determine which router will act as the MLD querier on the subnet.  

1)  Initially, every MLD router assumes itself as the querier and sends MLD general query messages 

(often referred to as general queries) to all hosts and routers on the local subnet (the destination 

address is FF02::1).  

2)  Upon hearing a general query, every MLD router compares the source IPv6 address of the query 

message with its own interface address. After comparison, the router with the lowest IPv6 address 

wins the querier election and all other routers become non-queriers.  

3)  All the non-queriers start a timer, known as “other querier present timer”. If a router receives an 

MLD query from the querier before the timer expires, it resets this timer; otherwise, it assumes that 

the querier has timed out and initiates a new querier election process.