IPV6 with Cisco layer 2 switches.

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Dec 15th, 2008

I know IPV6 affects only layer 3 switches, but I heard that it also could affect layer 2 switches with VLANs. Is this true? I have Cisco 3500 / 2900 layer 2 switches. Please advise. Thanks

I have this problem too.
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Giuseppe Larosa Fri, 12/19/2008 - 07:00


IPv6 over ethernet are still ethernet frames.

A layer2 switch doesn't care about the L3 protocol it is interested only on L2 PDUs called frames and performs forwarding based on MAC addresses

I think you can support IPv6 frames on your switches

Hope to help


Additional information:

On layer-2 or layer-3 switches, you need to also look at the device specific features. for instance,

3600 series switches have only one TCAM to store unicast routes, MAC addresses, and other ACL rules etc. To allocate TCAM resources for different usages, the switch SDM templates prioritize system resources to optimize support for certain features"

so by using "sdm prefer dual-ipv4-and-ipv6 routing" and reloading the switch, you can access ipv6 command.

ahoude333 Wed, 02/11/2009 - 09:20

Thank you for the infor regarding layer-2


I have a Cisco 4948 switch that I would like to ipv6 tunnel. Is there a config file I can use as an example.

I tried looking for cisco ipv6 switch documents, but I seemed to get only boarder routers for ipv6 to ipv4.

I want to go ipv6 to ipv4 corporate network and to end point ipv6.



ahoude333 Wed, 02/11/2009 - 13:15

Thank you for the infor.

Is there a way to have 6to4 automatic tunnelling enabled on Cisco IOS (Cisco 4948 switch) allowing properly formatted 6to4 packets to be decoded by the Cisco and forwarded on as ipv6 packets to another PC?

ahoude333 Wed, 02/11/2009 - 15:39

Thanks again but I have this layer 3 switch (4948) and it appears to have all the commands to configure ipv6 tunnel.

If it does not support tunnel, what does Cisco 4948 layer 3 switch provide under IPv6?

This is a link which shows tunneling under a 6500 switches with encapsulation/decapsulation. This is why I thought I could do the same with 4948 switch but apparently not...



Paolo Bevilacqua Thu, 02/12/2009 - 01:55

Hi, sometime cisco products have the commands but these do not work. Refer to the documentaion for you switch to know it supports.

ahoude333 Thu, 02/12/2009 - 08:50

Thanks for the advice. I will setup cisco boarder routers. I have the following routers: 2514, 2811, and 2611. I have multiple of these flavors. I know the 2514 and 2611 are discontinued so I do know if ipv6 is supported and the 2811 I am not seeing that it supports ipv6.

Do you believe that I can use any of these routers and if so what level of IOS supports ipv6 tunneling.

If I can not use any of these routers could recommend what I should use for ipv6 tunneling.

Thanks for your help.

Paolo Bevilacqua Thu, 02/12/2009 - 08:54

All these are fine except perhaps the 2514 and the 2611 if not XM. You need a recent IOS, advanced IP services.


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