6to4 relay on IOS <-> CEF switching?

[David Prall]

Gert,
The feature is called
"IPv6 Switching: CEFv6 Switched Automatic IPv4-compatible Tunnels"

http://www.cisco.com/en/US/docs/ios/ipv6/configuration/guide/ip6-roadmap.htm
l

First release was 12.3(2)T. So 12.3T or 12.4 should work well.

David

--
http://dcp.dcptech.com
 

> -----Original Message-----
> From: ipv6-ops-bounces+dcp=dcptech.com at lists.cluenet.de [mailto:ipv6-
> ops-bounces+dcp=dcptech.com at lists.cluenet.de] On Behalf Of Gert Doering
> Sent: Thursday, October 09, 2008 5:37 AM
> To: ipv6-ops at lists.cluenet.de
> Subject: 6to4 relay on IOS <-> CEF switching?
> 
> Hi Folks,
> 
> we've just moved our 6to4 relay to a new router (well, it's still an
> old
> router, but a dedicated machine to that purpose).
> 
> It's a 3640 with 12.3(22) on it, and "bog standard" 6to4 relay config:
> 
> interface Tunnel2002
>  description 6to4 relay - RFC 3056 (sp1)
>  no ip address
>  no ip redirects
>  load-interval 30
>  ipv6 address 2002:C195:2CD0::1/128
>  tunnel source 192.88.99.1
>  tunnel mode ipv6ip 6to4
> ipv6 route 2002::/16 Tunnel2002
> 
> ... and it's working well, that is, packets move back and forth and
> the latency is good.
> 
> What I'm unhappy about is the CPU load - these packets are not CEF
> switched
> ("show int switching" etc), and as such, measly 15 Mbit/s create 99%
> CPU
> load.
> 
> There is no fragmentation going on, so it seems to be more a matter of
> "CEF not supporting 6to4 in 12.3".
> 
> Before I start upgrading things (adding RAM etc) - what are your
> experiences
> with 6to4 relays on IOS?  Which combination of hardware and software
> are
> you using, and does it properly CEF switch these packets?
> 
> So far, I have received comments about 12.2SB, which seems to do CEF
> switching on egress but not on ingress (!?), and 12.4 on 2800, which
> seems to do both directions.
> 
> 
> (Just for the records: we're offering native IPv6 to all our customers,
> and
> we're not announcing the relay to "the world" - so something that can
> do 20-30 mbit/s is perfectly fine for our needs, as in 'the occasional
> customer that has never considered IPv6 but 6to4 just happened to his
> machine by virtue of a MacOS device nearby')
> 
> Gert Doering
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