1-6
Table 1-3
Types and functions of ICMPv6 messages
ICMPv6 message
Function
Used to acquire the link-layer address of a neighbor
Used to verify whether the neighbor is reachable
Neighbor solicitation (NS) message
Used to perform a duplicate address detection
Used to respond to a neighbor solicitation message
Neighbor advertisement (NA)
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.
Used to respond to a router solicitation message
Router advertisement (RA)
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.
z
3Com Switch 4210 Family do not support RS, RA, or Redirect message.
z
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 1-3
shows how node A acquires the link-layer address
of node B.
