H3C S7500E Series Operation Manual page 574

Operation Manual – IPv6 Configuration
H3C S7500E Series Ethernet Switches
ICMPv6 message
Router advertisement
(RA) message
Redirect message
The NDP mainly provides the following functions:
I. Address resolution
Similar to the ARP function in IPv4, a node acquires the link-layer addresses of
neighbor nodes on the same link through NS and NA messages.
node A acquires the link-layer address of node B.
Figure 1-3 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 an interface of node A and the destination address is the
solicited-node multicast address of node B. The NS message contains the
link-layer address of node A.
2) After receiving the NS message, node B judges whether the destination address
of the packet corresponds to the solicited-node multicast address. If yes, node B
can learn the link-layer address of node A, and unicasts an NA message
containing its link-layer address.
3) Node A acquires the link-layer address of node B from the NA message.
II. Neighbor reachability detection
After node A acquires the link-layer address of its neighbor node B, node A can verify
whether node B is reachable according to NS and NA messages.
Number
Used to respond to an RS message
With the RA message suppression disabled,
134
the router regularly sends an RA message
containing information such as prefix
information options and flag bits.
When a certain condition is satisfied, the
default gateway sends a redirect message to
137
the source host so that the host can reselect a
correct next hop router to forward packets.
1-8
Chapter 1 IPv6 Basics Configuration
Function
Figure 1-3 shows how