[c-nsp] 6500 router hangs (IPV4 routing slows to a crawl) when IPV6 routing is enabled with VRFs.

[Jim Trotz]

Thanks Nick,

here is the CLI output during the hangup:

MTWDAVTSTEE001#show mls cef summary

Total routes:                                    407605
    IPv4 unicast routes:                         407557
        IPv4 non-vrf routes:                     30
        IPv4 vrf routes:                         407527
    IPv4 Multicast routes:                       4
    MPLS routes:                                 8
    IPv6 unicast routes:                         32
        IPv6 non-vrf routes:                     5
        IPv6 vrf routes:                         27
    IPv6 multicast routes:                       3
    EoM routes:                                  1
MTWDAVTSTEE001#show platform hardware capacity forwarding
L2 Forwarding Resources
           MAC Table usage:   Module  Collisions  Total       Used
%Used

    The slot 5 is busy, try later. Status = 8

             VPN CAM usage:                       Total       Used
%Used
                                                    512          9
2%
L3 Forwarding Resources
             FIB TCAM usage:                     Total        Used
%Used
                  72 bits (IPv4, MPLS, EoM)     524288      407557
78%
                 144 bits (IP mcast, IPv6)      262144         294
1%

                     detail:      Protocol                    Used
%Used
                                  IPv4                      407548
78%
                                  MPLS                           8
1%
                                  EoM                            1
1%

                                  IPv6                         287
1%
                                  IPv4 mcast                     4
1%
                                  IPv6 mcast                     3
1%

            Adjacency usage:                     Total        Used
%Used
                                               1048576         178
1%

     Forwarding engine load:
                     Module       pps   peak-pps
peak-time
                     5          22006      53376  21:48:00 est Sun Jun 10
2012

=========================================

Were not using ipv4 or ipv6 urpf.

Were not passing any IPV6 traffic (i.e. no fragments) at this point since
we never got to adding any of the IPV6 addresses or turn up any routing -
just these 3 commands "mls ipv6 vrf", "vrf def with ipv6 address-family"
and "ipv6 unicast-routing".

if you notice in the above CLI output " The slot 5 is busy, try later.
Status = 8" this is because the SP goes to 99% cpu utilization on the "CFIB
LC QUEUE BO" process for about 5 minutes.

I am going to try (in our lab) to reconfigure the box to put the Internet
routes in the global table and the "inside" routes in a VRF (swap the
tables).