ZyXEL Communications P-870HN-5xb User Manual page 360

Appendix E IPv6
ICMPv6
Internet Control Message Protocol for IPv6 (ICMPv6 or ICMP for IPv6) is defined in
RFC 4443. ICMPv6 has a preceding Next Header value of 58, which is different
from the value used to identify ICMP for IPv4. ICMPv6 is an integral part of IPv6.
IPv6 nodes use ICMPv6 to report errors encountered in packet processing and
perform other diagnostic functions, such as "ping".
Multicast Listener Discovery
The Multicast Listener Discovery (MLD) protocol (defined in RFC 2710) is derived
from IPv4's Internet Group Management Protocol version 2 (IGMPv2). MLD uses
ICMPv6 message types, rather than IGMP message types. MLDv1 is equivalent to
IGMPv2 and MLDv2 is equivalent to IGMPv3.
MLD allows an IPv6 switch or router to discover the presence of MLD listeners who
wish to receive multicast packets and the IP addresses of multicast groups the
hosts want to join on its network.
MLD snooping and MLD proxy are analogous to IGMP snooping and IGMP proxy in
IPv4.
MLD filtering controls which multicast groups a port can join.
MLD Messages
A multicast router or switch periodically sends general queries to MLD hosts to
update the multicast forwarding table. When an MLD host wants to join a
multicast group, it sends an MLD Report message for that address.
An MLD Done message is equivalent to an IGMP Leave message. When an MLD
host wants to leave a multicast group, it can send a Done message to the router
or switch. The router or switch then sends a group-specific query to the port on
which the Done message is received to determine if other devices connected to
this port should remain in the group.
Transition Techniques
IPv6 Over IPv4 Tunnelling
To route traffic between two IPv6 networks over an IPv4 network, an IPv6 over
IPv4 tunnel has to be used.
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P-870HN-5xb User's Guide