[c-nsp] IPv6 over GRE or IPv6IP tunneling on sup32

[Michael Ulitskiy]

On Tuesday 25 May 2010 01:48:02 am Mikael Abrahamsson wrote:
> On Mon, 24 May 2010, Michael Ulitskiy wrote:
> 
> > Hello,
> >
> > Does anybody know if sup32/PFC3B support hardware forwarding of ipv6 over GRE or ipv6ip tunnels?
> > IOS 12.2(33)SXH4. I can't find a definitive answer in cisco doc.
> > I know "tunnel mode gre" runs in hardware, but I'm not sure if ipv6 on top of it will make any difference.
> > Has anybody tried it?
> 
> I know for a fact that "tunnel mode ipv6ip" is hw path on a Sup720 (if 
> it's the only tunnel using that loopback IP as tunnel IP), so should be on 
> sup32 as well?
> 


My understanding is that sup32 should be no differenct.
Anyway it seems you're right.
I've made the following little lab - Tu0 is IPv6 over GRE tunnel and Tu1 is IPv6IP.

interface Tunnel0
 no ip address
 load-interval 30
 ipv6 address xxxx:yyyy:FFFE:1::1/64
 ipv6 enable
 no snmp trap link-status
 tunnel source Loopback0
 tunnel destination a.b.c.d
!
interface Tunnel1
 no ip address
 load-interval 30
 ipv6 address xxxx:yyyy:FFFE:2::1/64
 ipv6 enable
 no snmp trap link-status
 tunnel source Loopback1
 tunnel destination a.b.c.d
 tunnel mode ipv6ip
!

Here's what I see:

CORE1#sh mls cef ipv6

Codes: + - Push label
Index  Prefix                              Adjacency
...
196864 xxxx:yyyy:FFFE:1::/64               punt
196866 xxxx:yyyy:FFFE:2::/64               Tu1             a.b.c.d
...

GRE tunnel (Tu0) has punt adjacency, while ipv6ip tunnel has Tu1 adjacency.
Also I've put some traffic on both tunnels and here's what I got:

CORE1#sh int tu0 stats
Tunnel0
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor          3        264          3        408
             Route cache       4212    5677980      27110   25666796
       Distributed cache      10152    6065737          0          0
                   Total      14367   11743981      27113   25667204

CORE1#sh int tu1 stats
Tunnel1
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor          9       1078         58       5680
             Route cache          0          0          0          0
       Distributed cache      29935   29559402      21701   20714008
                   Total      29944   29560480      21759   20719688

Most ipv6 over GRE traffic is in route cache path, while most ipv6ip traffic
in distributed cache. I'm not sure what the difference between them, but my
guess is that route cache is software CEF, while distributed cache is PFC3.
Am I right?
Is there any better way to confirm it?
Thanks,

Michael