Brocade Communications Systems FastIron SX 1600, Configuration Manual, Page: 170 / 593

IPv6 neighbor discovery configuration notes
NOTE
For all solicitation and advertisement messages, Brocade uses seconds as the unit of measure instead of milliseconds.
• If you add a port to a port-based VLAN, and the port has IPv6 neighbor discovery configuration, the system will clean up the
neighbor discovery configuration from the port and display the following message on the console.
ND6 port config on the new member ports removed
• Neighbor discovery is not supported on tunnel interfaces.
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.
IPv6 neighbor discovery configuration
FastIron Ethernet Switch Layer 3 Routing
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