[cisco-nas] Input queues drops on IOS 12.3(10)

[Jaco Engelbrecht]

Hi,

I'm running Cisco IOS 12.3(10) (c5300-is-mz.123-10.bin) on AS5300's and am experiencing input queue drops on my FE interfaces:

 Input queue: 513/512/162151/65 (size/max/drops/flushes); Total output drops: 0

 FastEthernet0 buffers, 1554 bytes (total 512, permanent 512):
     0 in free list (0 min, 512 max allowed)
     113965 hits, 93199 fallbacks
     192 max cache size, 0 in cache
     945985415 hits in cache, 206948 misses in cache

Increasing the hold-queue to 2096 get the packets flowing again:

 Input queue: 545/2096/162496/65 (size/max/drops/flushes); Total output drops: 0

I've captured 'sh ip cache flow', 'sh tech-support' output, going through this doesn't show me obvious evidence of who the culprit is sending packets to my FE interface, which would result in packets being queued and then resulting in input queue drops and my NASs dissapearing off the network.  The NAS CPU load is only at 23% according to 'show tech-support' output.  CEF is enabled globally, and CEF switching enabled on the FE:

 #sh ip int fa0 | i CEF
  IP CEF switching is enabled
  IP CEF Feature Fast switching turbo vector
  IP route-cache flags are Fast, CEF

The only traffic that I'm seeing destined to my FE is SGBP traffic to/from my other NASs.  I've got ~22 NASs running SGBP in this particular POP - I am not sure that this is causing the problem though - I've seen my input queues fill up in smaller POPs, which only got two SGBP members.

Any hints/ideas on what to look for in my cache flow data?  Should I increase the hold-queue to 1024 for input packets on fa0?

I've had similar issues on IOS 12.2.(19) as well.  What is the current recommended code for AS5300 and AS5400's?

Already had a read at http://www.cisco.com/warp/public/63/queue_drops.html...

Cheers,
Jaco

-- 
bje at serendipity.org.za
the faculty of making fortunate discoveries