IPv6 neighbor discovery conguration 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 conguration, the system will clean up the
neighbor discovery conguration 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
eld 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 eld 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 congured router interface on a link sends out a router advertisement message, which has a value of 134 in the Type eld of the
ICMP packet header, periodically to the all-nodes link-local multicast address (FF02::1).
A congured 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 eld of the ICMP packet header, enables the host to automatically congure
its IPv6 address immediately instead of awaiting the next periodic router advertisement message.
IPv6 neighbor discovery conguration
FastIron Ethernet Switch Layer 3 Routing
170 53-1003627-04
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