530 CHAPTER 46: IPV6 MANGEMENT CONFIGURATION
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■ 3Com Switch 4210 Family do not support RS, RA, or Redirect message.
■ Of the above mentioned IPv6 NDP functions, 3Com Switch 4210 Family
support the following three functions: address resolution, neighbor
unreachability detection, and duplicate address detection. The subsequent
sections present a detailed description of these three functions and relevant
configuration.
The NDP mainly provides the following functions:
Address resolution
Similar to the ARP function in IPv4, a node acquires the link-layer address of
neighbor nodes on the same link through NS and NA messages.
Figure 191 shows
how node A acquires the link-layer address of node B.
Figure 191 Address resolution
The address resolution procedure is as follows:
1 Node A multicasts an NS message. The source address of the NS message is the
IPv6 address of the interface of node A and the destination address is the
Neighbor advertisement (NA)
message
Used to respond to a neighbor solicitation message
When the link layer address changes, the local node initiates a
neighbor advertisement message to notify neighbor nodes of
the change.
Router solicitation (RS)
message
After started, a host sends a router solicitation message to
request the router for an address prefix and other configuration
information for the purpose of autoconfiguration.
Router advertisement (RA)
message
Used to respond to a router solicitation message
With the RA message suppression disabled, the router regularly
sends a router advertisement message containing information
such as address prefix and flag bits.
Redirect message When a certain condition is satisfied, the default gateway sends
a redirect message to the source host so that the host can
reselect a correct next hop router to forward packets.
Table 385 Types and functions of ICMPv6 messages
ICMPv6 message Function
Src=A
Dst=solicited- node multicast of B
ICMP type=136
Src=B
Dst=A
Data=link- layer address of B
NS
NA
AB
ICMP type=135
Data=link- layer address of A
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