[c-nsp] Loop/Unreachable problem with C6500/SUP720

[Sebastian Wiesinger]

* Randy <randy_94108 at yahoo.com> [2012-08-08 21:35]:
> ...also curious:
> 
> If there is a discrepancy between "sh ip cef <perfix>" and "sh ip
> cef <prefix> internal" for prefixes in question.

Here is the working prefix:

$ ping 10.1.66.51
PING 10.1.66.51 (10.1.66.51) 56(84) bytes of data.
64 bytes from 10.1.66.51: icmp_req=1 ttl=60 time=3.93 ms
64 bytes from 10.1.66.51: icmp_req=2 ttl=60 time=3.97 ms
64 bytes from 10.1.66.51: icmp_req=3 ttl=60 time=3.98 ms

And the bad one:

$ ping 10.1.66.84
PING 10.1.66.84 (10.1.66.84) 56(84) bytes of data.
>From 10.2.14.9 icmp_seq=1 Time to live exceeded
>From 10.2.14.9 icmp_seq=2 Time to live exceeded
>From 10.2.14.9 icmp_seq=3 Time to live exceeded


We start with show ip cef:

lab-rtr1#show ip cef 10.1.66.51
10.1.66.51/32
  attached to Vlan412

lab-rtr1#show ip cef 10.1.66.84
10.1.66.84/32
  attached to Vlan412


We go on with show ip cef internal:

lab-rtr1#show ip cef 10.1.66.51 internal 
10.1.66.51/32, epoch 7, flags attached, refcount 5, per-destination sharing
  sources: Adj 
  feature space:
   NetFlow: Origin AS 0, Peer AS 0, Mask Bits 25
  subblocks:
   Adj source: IP adj out of Vlan412, addr 10.1.66.51 5136EEC0
    Dependent covered prefix type adjfib cover 10.1.66.0/25
  ifnums:
   Vlan412(180): 10.1.66.51
  path 5110F968, path list 5110C090, share 1/1, type adjacency prefix, for IPv4
  attached to Vlan412, adjacency IP adj out of Vlan412, addr 10.1.66.51 5136EEC0
  output chain: IP adj out of Vlan412, addr 10.1.66.51 5136EEC0

lab-rtr1#show ip cef 10.1.66.84 internal 
10.1.66.84/32, epoch 7, flags attached, refcount 5, per-destination sharing
  sources: Adj 
  feature space:
   NetFlow: Origin AS 0, Peer AS 0, Mask Bits 25
  subblocks:
   Adj source: IP adj out of Vlan412, addr 10.1.66.84 5136A6C0
    Dependent covered prefix type adjfib cover 10.1.66.0/25
  ifnums:
   Vlan412(180): 10.1.66.84
  path 51110C70, path list 5110D2F8, share 1/1, type adjacency prefix, for IPv4
  attached to Vlan412, adjacency IP adj out of Vlan412, addr 10.1.66.84 5136A6C0
  output chain: IP adj out of Vlan412, addr 10.1.66.84 5136A6C0


And show mls cef detail / mls adjacency:

lab-rtr1#show mls cef 10.1.66.51 detail 

Codes: M - mask entry, V - value entry, A - adjacency index, P - priority bit
       D - full don't switch, m - load balancing modnumber, B - BGP Bucket sel
       V0 - Vlan 0,C0 - don't comp bit 0,V1 - Vlan 1,C1 - don't comp bit 1
       RVTEN - RPF Vlan table enable, RVTSEL - RPF Vlan table select
Format: IPV4_DA - (8 | xtag vpn pi cr recirc tos prefix)
Format: IPV4_SA - (9 | xtag vpn pi cr recirc prefix)
M(313    ): E | 1 FFF  0 0 0 0   255.255.255.255
V(313    ): 8 | 1 0    0 0 0 0   10.1.66.51      (A:425985 ,P:1,D:0,m:0 ,B:0 )

lab-rtr1#show mls cef adjacency entry 425985

Index: 425985  smac: 0003.3245.0000, dmac: 0023.ae67.936e
               mtu: 1518, vlan: 412, dindex: 0x0, l3rw_vld: 1
               packets: 0, bytes: 0

lab-rtr1#show mls cef 10.1.66.84 detail  

Codes: M - mask entry, V - value entry, A - adjacency index, P - priority bit
       D - full don't switch, m - load balancing modnumber, B - BGP Bucket sel
       V0 - Vlan 0,C0 - don't comp bit 0,V1 - Vlan 1,C1 - don't comp bit 1
       RVTEN - RPF Vlan table enable, RVTSEL - RPF Vlan table select
Format: IPV4_DA - (8 | xtag vpn pi cr recirc tos prefix)
Format: IPV4_SA - (9 | xtag vpn pi cr recirc prefix)
M(345    ): E | 1 FFF  0 0 0 0   255.255.255.255
V(345    ): 8 | 1 0    0 0 0 0   10.1.66.84      (A:442370 ,P:1,D:0,m:0 ,B:0 )

lab-rtr1#show mls cef adjacency entry 442370

Index: 442370  smac: 0003.3245.0000, dmac: 0023.ae67.936e
               mtu: 1518, vlan: 412, dindex: 0x0, l3rw_vld: 1
               packets: 0, bytes: 0


As far as I see, it looks OK. The problem lies somewhere deeper at the
hardware level.

Regards

Sebastian

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