Brocade Multi-Service IronWare Routing Configuration Guide (Supporting R05.6.00) - Manual (Page 472)

444 Multi-Service IronWare Routing Configuration Guide
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Configuring IPv6 neighbor discovery
• Router advertisement messages:
• Interval between router advertisement messages.
• Value that indicates a device is advertised as a default device (for use by all nodes on a
given link).
• Prefixes advertised in router advertisement messages.
• Flags for host stateful autoconfiguration.
• The time that an IPv6 node considers a remote node reachable (for use by all nodes on a given
link).
The default maximum value for IPv6 neighbor discovery (ND) entries is 4096 for Brocade NetIron
XMR and Brocade MLX series devices.
The memory is allocated for IPv4 and IPv6 separately. The maximum IPv4 ARP and IPv6 ND entries
can be supported together.
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 devices on
the same link.