Viewing IPv6 router information


show ipv6 routers [vlan <vid>]

Lists the IPv6 router table entries for all VLANs configured on the switch or for a single VLAN. This output provides information about the IPv6 routers from which RAs have been received on the switch.


This command reports on IPv6 routers the switch has learned of through operation as a host or client of a router. If the switch itself is configured as an IPv6 router (routing switch), the output of this command is empty.

vlan <vid> : Optional. Specifies only the information on IPv6 routers on the indicated VLAN.

Router Address : The IPv6 address of the router interface.

Preference : The relative priority of prefix assignments received from the router when prefix assignments are also received on the same switch VLAN interface from other IPv6 routers.

Interface : The VLAN interface on which the router exists.

MTU : The maximum transmission unit (in bytes) allowed for frames on the path to the indicated router.

Hop Limit : The maximum number of router hops allowed.

Prefix Advertised : Lists the prefix and prefix size (number of leftmost bits in an address) originating with the indicated router.

Valid Lifetime : The total time the address is available, including the preferred lifetime and the additional time (if any) allowed for the address to exist in the deprecated state. See Valid lifetime.

Preferred Lifetime : The length of time during which the address can be used freely as both a source and a destination address for traffic exchanges with other devices. See Preferred lifetime.

On/Off Link : Indicates whether the entry source is on the same VLAN as is indicated in the Interface field.

The display below indicates that the switch is receiving RAs from a single router that exists on VLAN 10.
Switch(config)# show ipv6 routers

 IPv6 Router Table Entries

  Router Address : fe80::213:c4ff:fedd:14b0
  Preference     : Medium
  Interface      : VLAN10
  MTU            : 1500
  Hop Limit      : 64

                             Valid        Preferred    On/Off
  Prefix Advertised          Lifetime(s)  Lifetime(s)  Link
  –––––––––––––––––––––––––– –––––––––––– –––––––––––– –––––––
  2001:db8:a03:e102::/64     864000       604800       Onlink