Brocade Communications Systems 6650 IPv6 CLI command support, IPv6 stateless auto-configuration

5 IPv6 CLI command support

IPv6 stateless auto-configuration

Brocade routers use the IPv6 stateless autoconfiguration feature to enable a host on a local link to automatically configure its interfaces with new and globally unique IPv6 addresses associated with its location. The automatic configuration of a host interface is performed without the use of a server, such as a Dynamic Host Configuration Protocol (DHCP) server, or manual configuration.

The automatic configuration of a host interface works in the following way: a switch on a local link periodically sends switch advertisement messages containing network-type information, such as the 64-bit prefix of the local link and the default route, to all nodes on the link. When a host on the link receives the message, it takes the local link prefix from the message and appends a 64-bit interface ID, thereby automatically configuring its interface. (The 64-bit interface ID is derived from the MAC address of the host’s NIC.) The 128-bit IPv6 address is then subjected to duplicate address detection to ensure that the address is unique on the link.

The duplicate address detection feature verifies that a unicast IPv6 address is unique before it is assigned to a host interface by the stateless auto configuration feature. Duplicate address detection uses neighbor solicitation messages to verify that a unicast IPv6 address is unique.

NOTE

For the stateless auto configuration feature to work properly, the advertised prefix length in switch advertisement messages must always be 64 bits.

The IPv6 stateless autoconfiguration feature can also automatically reconfigure a host’s interfaces if you change the ISP for the host’s network. (The host’s interfaces must be renumbered with the IPv6 prefix of the new ISP.)

The renumbering occurs in the following way: a switch on a local link periodically sends advertisements updated with the prefix of the new ISP to all nodes on the link. (The advertisements still contain the prefix of the old ISP.) A host can use the addresses created from the new prefix and the existing addresses created from the old prefix on the link. When you are ready for the host to use the new addresses only, you can configure the lifetime parameters appropriately using the ipv6 nd prefix-advertisementcommand. During this transition, the old prefix is removed from the switch advertisements. At this point, only addresses that contain the new prefix are used on the link.

IPv6 CLI command support

Table 23 lists the IPv6 CLI commands supported.

TABLE 23	IPv6 CLI command support
IPv6 command		Description	Switch code	Router code
clear ipv6	cache	Deletes all entries in the dynamic host cache.		X
clear ipv6 mld-snooping		Deletes MLD-snooping-related counters or cache	X	X
		entries.
clear ipv6 neighbor		Deletes all dynamic entries in the IPv6 neighbor	X	X
		table.
clear ipv6 ospf		Clears OSPF-related entries.		X
clear ipv6 rip		Clears RIP-related entries.		X
clear ipv6 route		Deletes all dynamic entries in the IPv6 route table.		X
clear ipv6 traffic		Resets all IPv6 packet counters.	X	X

104	Brocade ICX 6650 Administration Guide
	53-1002600-01