3Com Switch 8800 Advanced Software V5 Configuration Guide

216 CHAPTER 23: IPV6 BASICS CONFIGURATION
■ “Neighbor reachability detection” on page 218
■ “Duplicate address detection” on page 218
■ “Router/prefix discovery and address autoconfiguration” on page 218
■ “Redirection” on page 219
Table 21 lists the types and functions of ICMPv6 messages used by the NDP.
Tabl e 21 Types and functions of ICMPv6 messages
ICMPv6 message Number Function
Neighbor solicitation (NS)
message
135 Used to acquire the link-layer
address of a neighbor
Used to verify whether the
neighbor is reachable
Used to perform a duplicate
address detection
Neighbor advertisement (NA)
message
136 Used to respond to an NS
message
When the link layer changes,
the local node initiates an NA
message to notify neighbor
nodes of the node
information change.
Router solicitation (RS)
message
133 After started, a host sends an
RS message to request the
router for an address prefix
and other configuration
information for the purpose
of autoconfiguration.
Router advertisement (RA)
message
134 Used to respond to an RS
message
With the RA message
suppression disabled, the
router regularly sends an RA
message containing
information such as address
prefix and flag bits
Redirect message 137 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.
Neighbor solicitation (NS)
message
135 Used to acquire the link-layer
address of a neighbor.
Used to verify whether the
neighbor is reachable.
Used to perform a duplicate
address detection.