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I have two identical Layer 3 switches, running identical Cisco IOS Versions. One of the switches, I can configure with ipv6. The other switch however, tells me "Unrecognized command" when I try any ipv6 commands. This includes commands inside a Vlan interface, and not just ipv6 general settings.

Good Switch:

ns-sw03#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
ns-sw03(config)#ipv6 ?
  access-list      Configure access lists
  cef              Cisco Express Forwarding for IPv6
  dhcp             Configure IPv6 DHCP
  general-prefix   Configure a general IPv6 prefix
  hop-limit        Configure hop count limit
  host             Configure static hostnames
  icmp             Configure ICMP parameters
  local            Specify local options
  mld              Global MLD Snooping enable for Catalyst Vlans
  nd               Configure IPv6 ND
  neighbor         Neighbor
  ospf             OSPF
  prefix-list      Build a prefix list
  route            Configure static routes
  router           Enable an IPV6 routing process
  source-route     Process packets with source routing header options
  traffic          Configure traffic parameters
  unicast-routing  Enable unicast routing

Bad Switch:

ns-sw04#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
ns-sw04(config)#ipv6 ?
% Unrecognized command

The obvious answer to the question is "Your switch does not support the IPv6 Feature Set", but this doesn't make any sense because the firmware and IOS are identical on both switches.

Good Switch:

ns-sw03#show version
Cisco IOS Software, ME340x Software (ME340x-METROIPACCESSK9-M), Version 12.2(54)SE, RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2010 by Cisco Systems, Inc.
Compiled Tue 13-Apr-10 00:47 by prod_rel_team
Image text-base: 0x01000000, data-base: 0x02E00000

ROM: Bootstrap program is ME340x boot loader
BOOTLDR: ME340x Boot Loader (ME340x-HBOOT-M) Version 12.2(44)SE5, RELEASE SOFTWARE (fc1)

ns-sw03 uptime is 1 year, 40 weeks, 3 days, 9 hours, 19 minutes
System returned to ROM by power-on
System restarted at 03:44:43 CEST Sat Jul 9 2011
System image file is "flash:me340x-metroipaccessk9-mz.122-54.SE/me340x-metroipaccessk9-mz.122-54.SE.bin"

Bad Switch:

ns-sw04#show version
Cisco IOS Software, ME340x Software (ME340x-METROIPACCESSK9-M), Version 12.2(54)SE, RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2010 by Cisco Systems, Inc.
Compiled Tue 13-Apr-10 00:47 by prod_rel_team
Image text-base: 0x01000000, data-base: 0x02E00000

ROM: Bootstrap program is ME340x boot loader
BOOTLDR: ME340x Boot Loader (ME340x-HBOOT-M) Version 12.2(44)SE5, RELEASE SOFTWARE (fc1)

ns-sw04 uptime is 1 year, 40 weeks, 3 days, 9 hours, 16 minutes
System returned to ROM by power-on
System restarted at 03:46:15 CEST Sat Jul 9 2011
System image file is "flash:me340x-metroipaccessk9-mz.122-54.SE/me340x-metroipaccessk9-mz.122-54.SE.bin"

What have I missed?

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2 Answers 2

up vote 5 down vote accepted

I hope you're in a position to be able to reload the switch:

sdm prefer dual [default|routing|vlan]

and then reload, you should be good to go. Obviously this impacts the TCAM so do show sdm pref to make sure available resources reflect what you're going to need. I'd go with default unless you need to run a lot of IP routes.

Basically, IPv6 is only visible and enabled if the dual-stack SDM profile is selected.

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Thank you. While I am not able to do this now, I'm confident it will fix the problem. I've just verified that sw03 has template "desktop IPv4 and IPv6 routing" and sw04 has the "default" template, so it's clearly the right action to take. –  KeyszerS Apr 17 '13 at 12:59

It sounds like that switch is using the wrong SDM template. From the Cisco manual:

sdm prefer dual-ipv4-and-ipv6 {default | routing | vlan}

Select an SDM template that supports IPv4 and IPv6.

  • default: Set the switch to the default template to balance system resources.
  • routing: Set the switch to the routing template to support IPv4 and IPv6 routing, including IPv4 policy-based routing.
  • vlan: Maximize VLAN configuration on the switch with no routing supported in hardware.

After applying the new template you have to reboot the device for the configuration to become active.

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And yes: watch the TCAM usage –  Sander Steffann Apr 17 '13 at 12:22
1  
Ooh, two answers. I'll have to accept the first one, but I'll (try to) upvote yours since you did try to help :) Thank you. –  KeyszerS Apr 17 '13 at 12:57
    
You're welcome :) –  Sander Steffann Apr 17 '13 at 14:17

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