7600 IPv6 seeing mostly process switched - why?

[hennigan]

The 7600 platform is new to us, running 15.3(3)S6. IPv6 CEF distributed is enabled (default) but interface switching counts show 99% plus as being process switched. In fact, fast switching doesn't seem to be incrementing at all. We aren't in a mls cef exception state. IPv4 is happy with the vast majority of traffic fast switched.

Protocol  IPv6                
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
                 Process 2511553406 216878696408   77305286 9159052010
            Cache misses          0          -          -          -
                    Fast       5394     551574        366      56817
               Auton/SSE          0          0  588669997 124166174330

#sh mls cef exception status
Current IPv4 FIB exception state = FALSE
Current IPv6 FIB exception state = FALSE
Current MPLS FIB exception state = FALSE

[Philip D'Ath]

Which supervisor engine are you using and what software version?

Are you using PBR, IPv6 access lists, or anything else that involves anything other than plain IPv6 forwarding?

Could you share the config off one of your "typical" layer 3 interfaces with IPv6 enabled?

[hennigan]

Supervisor is RSP720-3CXL

No PBR or IPv6 access-lists

interface TenGigabitEthernet3/1
 description Level3
 ip address 4.x.x.x 255.255.255.252
 ip flow ingress
 ipv6 address 2001:x:x::x/126
 ipv6 enable
end

[Philip D'Ath]

Does "show ipv6 cef" show ipv6 entries?

[hennigan]

Yes, hundreds of them.

[i.fouraki]

Hi,

which command did you use to get this output? We are running 15.3(3)S3, but I cannot find a command that distinguishes ipv6 traffic.

Yanna

[hennigan]

"show interface switching"