Brocade BigIron RX Series Configuration Guide - Manual (Page 1262)

1184 BigIron RX Series Configuration Guide
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Configuring IPv6 neighbor discovery
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• Amount of time during which an IPv6 node considers a remote node reachable (for use by all
nodes on a given link).
Neighbor solicitation and advertisement messages
Neighbor solicitation and advertisement messages enable a node to determine the link-layer
address of another node (neighbor) on the same link. (This function is similar to the function
provided by the Address Resolution Protocol [ARP] in IPv4.) For example, node 1 on a link wants to
determine the link-layer address of node 2 on the same link. To do so, node 1, the source node,
multicasts a neighbor solicitation message. The neighbor solicitation message, which has a value
of 135 in the Type field of the ICMP packet header, contains the following information:
• Source address - IPv6 address of node 1 interface that sends the message.
• Destination address - solicited-node multicast address (FF02:0:0:0:0:1:FF00::/104) that
corresponds the IPv6 address of node 2.
• Link-layer address of node 1.
• A query for the link-layer address of node 2.
After receiving the neighbor solicitation message from node 1, node 2 replies by sending a
neighbor advertisement message, which has a value of 136 in the Type field of the ICMP packet
header. The neighbor solicitation message contains the following information:
• Source address - IPv6 address of the node 2 interface that sends the message.
• Destination address - IPv6 address of node 1.
• Link-layer address of node 2.
After node 1 receives the neighbor advertisement message from node 2, nodes 1 and 2 can now
exchange packets on the link.
After the link-layer address of node 2 is determined, node 1 can send neighbor solicitation
messages to node 2 to verify that it is reachable. Also, nodes 1, 2, or any other node on the same
link can send a neighbor advertisement message to the all-nodes multicast address (FF02::1) if
there is a change in their link-layer address.
Router advertisement and solicitation messages
Router advertisement and solicitation messages enable a node on a link to discover the routers on
the same link.
Each configured router interface on a link sends out a router advertisement message, which has a
value of 134 in the Type field of the ICMP packet header, periodically to the all-nodes link-local
multicast address (FF02::1).
A configured router interface can also send a router advertisement message in response to a
router solicitation message from a node on the same link. This message is sent to the unicast IPv6
address of the node that sent the router solicitation message.
At system startup, a host on a link sends a router solicitation message to the all-routers multicast
address (FF01). Sending a router solicitation message, which has a value of 133 in the Type field of
the ICMP packet header, enables the host to automatically configure its IPv6 address immediately
instead of awaiting the next periodic router advertisement message.