[c-nsp] IPv6 not Fast/CEF-switched on 3640 12.3T

[Oliver Boehmer (oboehmer)]

Daniel Roesen <> wrote on Monday, February 28, 2005 11:12 AM:

> On Mon, Feb 28, 2005 at 08:07:35AM +0100, Oliver Boehmer (oboehmer)
> wrote: 
>> I think IPv6 (unicast or multicast) over an IPv4 GRE tunnel is not
>> yet CEF-switched, "show cef not" should show increased counters in
>> "Unsupported" column.
> 
> CEF Packets passed on to next switching layer
> Slot  No_adj No_encap Unsupp'ted Redirect  Receive  Options   Access
> Frag RP         1       0       65462        0   509494        0     
> 0    0 IPv6 CEF Packets passed on to next switching layer
> Slot  No_adj No_encap Unsupp'ted Redirect  Receive  Options   Access 
> MTU RP         1       0       12853    39166     8448        0      
> 0    0 
> 
> Interestingly, the "Receive" number (509494) is the one rising when
> switching IPv6 multicast traffic from the GRE tunnel to Fas0/0, not
> the IPv6 Unsupp'ted number...

"Received" IPv4 packets also includes packets arriving from the GRE
tunnel.. 

>> Can you use a different tunnel encaps? ipv6-over-ipv4 (tunnel mode
>> ipv6ip) should provide better results..
> 
> Unfortunately not, as the tunnel must support MPLS and IS-IS...

Hmm, I fear there's not much I can do at this time if you need ISIS for
IPv6.. Otherwise you could create two tunnels, one GRE for MPLS and
IPv4, and one ipv6ip for IPv6 with possibly another routing protocol..

	oli