SNR S2989G-48TX-RPS — настройка IPv6 и протокол MLD: Руководство по конфигурации [535/553]

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S2989G-24TX Operation Manual

Chapter 11 IPv6 Configuration

11-25

intervening other routing configuration.

 When the network address mask of Black Hole Routing configuration is the same with

some other configuration, it is suggested that the distance of Black Hole Routing is

set lower.

For problems that cannot be fixed through above methods, please issue the

command show ip route distance and show ip route fib, and show l3. And copy and paste

the output of the commands, and send to the technical service center of our company.

11.5

IPv6 Multicast Protocol

11.5.1

MLD

11.5.1.1 Introduction to MLD

MLD (Multicast Listener Discovery) is the multicast group member (receiver)

discovery protocol serving IPv6 multicast. It is similar to IGMP Protocol in IPv4 multicast

application. Correspondingly, MLD Protocol version1 is similar to IGMP Protocol version2,

and MLD Protocol version2 is similar to IGMP Protocol version3. Current firmware

supports MLDv1/ MLDv2.

The IPv6 multicast hosts can join or leave from multicast group at any location, any

time, regardless of the total number of group members. It is unnecessary and impossible

for multicast switch to store the relationship among all host members. Multicast switch

simply finds out via MLD protocol if there are receivers of certain multicast group on the

network segment connected to each port. The only thing host need to do is to keep the

record of which multicast groups it joined.

MLD is unsymmetrical between host and switch: the host needs to respond the MLD

query message of multicast switch with membership report message; the switch

periodically sends membership query message and determines if there is host joining a

specific group in its subnetworks according to the response message received, and after it

receives the report of a host quitting from the group, it sends out the query for the group to

confirm if there is no member left in it.

There are three types of protocol messages of MLD Protocol, that is, Query, Report

and Done (which is corresponding to Leave of IGMPv2). Like IGMPV2, the Query

messages include General Query and Specific Group Query. General Query uses the

multicast address FF02::1 of hosts as destination address, the group address is 0; and

Specific Group Query use its group address as destination address. The multicast