ZyXEL Communications AMG1302-T11C, Руководство пользователя

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Appendix F IPv6
AMG1302-T11C User’s Guide
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uses the prefix list to determine whether the destination address is on-link and can be reached
directly without passing through a router. If the address is onlink, the address is considered as the
next hop. Otherwise, the AMG1302-T11C determines the next-hop from the default router list or
routing table. Once the next hop IP address is known, the AMG1302-T11C looks into the neighbor
cache to get the link-layer address and sends the packet when the neighbor is reachable. If the
AMG1302-T11C cannot find an entry in the neighbor cache or the state for the neighbor is not
reachable, it starts the address resolution process. This helps reduce the number of IPv6 solicitation
and advertisement messages.
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.
On the AMG1302-T11C, you can either set up a configured tunnel or an automatic 6to4 tunnel. The
following describes each method.
Configured Tunnel
A configured tunnel is a point-to-point tunnelling mechanism that encapsulates an IPv6 address
with an IPv4 address. Routers (
A and B ) on both IPv6 networks ( 1 and 2 ) each must have an
interface that connects to the IPv4 network (with an IPv4 address). This allows the router to send
and receive IPv6 data over the IPv4 network.
In this case, you must specify B ’s public IPv4 address on A (similarly, specify A ’s public IPv4
address on B ) in order for packets to arrive at the intended destination through the IPv4 network.