Neighbor redirect messages – Brocade BigIron RX Series Configuration Guide User Manual
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BigIron RX Series Configuration Guide
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Configuring IPv6 neighbor discovery
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Because a host at system startup typically does not have a unicast IPv6 address, the source
address in the router solicitation message is usually the unspecified IPv6 address
(0:0:0:0:0:0:0:0). If the host has a unicast IPv6 address, the source address is the unicast IPv6
address of the host interface sending the router solicitation message.
Entering the ipv6 unicast-routing command automatically enables the sending of router
advertisement messages on all configured router Ethernet interfaces. You can configure several
router advertisement message parameters. For information about disabling the sending of router
advertisement messages and the router advertisement parameters that you can configure, refer to
“Enabling and disabling IPv6 router advertisements”
Neighbor redirect messages
After forwarding a packet, by default, a router can send a neighbor redirect message to a host to
inform it of a better first-hop router. The host receiving the neighbor redirect message will then
readdress the packet to the better router.
A router sends a neighbor redirect message only for unicast packets, only to the originating node,
and to be processed by the node.
A neighbor redirect message has a value of 137 in the Type field of the ICMP packet header.
Setting neighbor solicitation parameters for duplicate
address detection
Although the stateless autoconfiguration feature assigns the 64-bit interface ID portion of an IPv6
address using the MAC address of the host’s NIC, duplicate MAC addresses can occur. Therefore,
the duplicate address detection feature verifies that a unicast IPv6 address is unique before it is
assigned to a host interface by the stateless autoconfiguration feature. Duplicate address
detection verifies that a unicast IPv6 address is unique.
If duplicate address detection identifies a duplicate unicast IPv6 address, the address is not used.
If the duplicate address is the link-local address of the host interface, the interface stops
processing IPv6 packets.
You can configure the following neighbor solicitation message parameters that affect duplicate
address detection while it verifies that a tentative unicast IPv6 address is unique:
•
The number of consecutive neighbor solicitation messages that duplicate address detection
sends on an interface. By default, duplicate address detection sends three neighbor
solicitation messages without any follow-up messages.
•
The interval in seconds at which duplicate address detection sends a neighbor solicitation
message on an interface. By default, duplicate address detection sends a neighbor solicitation
message every 1 second.
NOTE
For the interval at which duplicate address detection sends a neighbor solicitation message on an
interface, the Brocade device uses seconds as the unit of measure instead of milliseconds.
For example, to change the number of neighbor solicitation messages sent on Ethernet interface
3/1 to two and the interval between the transmission of the two messages to 9 seconds, enter the
following commands.