[c-nsp] cat 2950 no buffer incrementing?

Tue Apr 11 22:16:34 EDT 2006

hi all,

firstly thank you for taking the time to read this email :) ive got a cat
2950 that has started to exhibit some unusual behaviour i am hoping someone
can help me with. the topology is that the 2950 is acting as an edge with
fa0/1-24 as vlan access ports and g0/1 as a 1q trunk. it is one of many
2950's uplinked in an identical fashion to the same 3750. 

if i put a management ip on the switch in any vlan i find that it lags but
the console is ok. 

10.1.1.86: icmp_seq=0 ttl=254 time=687.9 ms
10.1.1.86: icmp_seq=1 ttl=254 time=696.4 ms

however pings/ftps to a device behind the switch (attached to port fa0/1)
are perfectly fine.

192.168.1.2: icmp_seq=0 ttl=64 time=0.7 ms
192.168.1.2: icmp_seq=1 ttl=64 time=0.3 ms

so it seems apparent that the lagging only affects traffic going to the
switch itself but not traffic being passed through the switch..

when i check the gigabit uplink i find that the no buffer counter is
incrementing continously.. but this switch is doing hardly any traffic
(.3mbps on the gig uplink), only has half its ports actually provisioned and
has plenty of buffers and memory available. (compared to its friends who are
running same ios, have been up longer, have 24 ports in use and have an
uplink port doing 200+mbps) ive also tried creating a fresh vlan and
dropping the switch's management ip into that instead of using the native
vlan but it didnt make any difference.

i would expect that the no buffers counter being incremented on a show
interface should correlate to the misses counter on a show buffers
incrementing also, but this isnt the case at all, despite the fact the
interface is claiming no buffers the buffer misses are not incrementing at
all.

ideas anyone???

30 second sample

ir-swaccess1#sh int g0/1
  30 second input rate 197000 bits/sec, 187 packets/sec
  30 second output rate 13000 bits/sec, 6 packets/sec
     5792 packets input, 772900 bytes, 780 no buffer
     Received 5457 broadcasts (0 multicast)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 780 ignored
     0 watchdog, 4983 multicast, 0 pause input
     0 input packets with dribble condition detected
     150 packets output, 29973 bytes, 0 underruns
     0 output errors, 0 collisions, 0 interface resets
     0 babbles, 0 late collision, 0 deferred
     0 lost carrier, 0 no carrier, 0 PAUSE output
     0 output buffer failures, 0 output buffers swapped out
ir-swaccess1#

ir-swaccess1#sh control g0/1 util
Receive Bandwidth Percentage Utilization   : 0
Transmit Bandwidth Percentage Utilization  : 0

ir-swaccess1#sh proc cpu
CPU utilization for five seconds: 5%/1%; one minute: 3%; five minutes: 3%

ir-swaccess1#sh mem sum
                Head    Total(b)     Used(b)     Free(b)   Lowest(b)
Largest(b)
Processor   80B70080     5025664     2519892     2505772     1969488
2310428
      I/O   A08B4C00     2864224      692688     2171536     2138972
2169980

ir-swaccess1#sh buf
Buffer elements:
     494 in free list (500 max allowed)
     136260826 hits, 0 misses, 0 created

Public buffer pools:
Small buffers, 104 bytes (total 25, permanent 25, peak 109 @ 7w0d):
     25 in free list (20 min, 60 max allowed)
     92959949 hits, 40 misses, 112 trims, 112 created
     0 failures (0 no memory)
Middle buffers, 600 bytes (total 28, permanent 15, peak 39 @ 7w0d):
     27 in free list (10 min, 30 max allowed)
     3182439 hits, 5277 misses, 6291 trims, 6304 created
     6 failures (0 no memory)
Big buffers, 1524 bytes (total 6, permanent 5, peak 11 @ 7w0d):
     6 in free list (5 min, 10 max allowed)
     1966788 hits, 83 misses, 1439 trims, 1440 created
     0 failures (0 no memory)
VeryBig buffers, 4520 bytes (total 0, permanent 0):
     0 in free list (0 min, 10 max allowed)
     0 hits, 0 misses, 0 trims, 0 created
     0 failures (0 no memory)
Large buffers, 5024 bytes (total 0, permanent 0):
     0 in free list (0 min, 5 max allowed)
     0 hits, 0 misses, 0 trims, 0 created
     0 failures (0 no memory)
Huge buffers, 18024 bytes (total 0, permanent 0):
     0 in free list (0 min, 2 max allowed)
     0 hits, 0 misses, 0 trims, 0 created
     0 failures (0 no memory)

Interface buffer pools:
Calhoun Packet Receive Pool buffers, 1560 bytes (total 256, permanent 256):
     223 in free list (0 min, 256 max allowed)
     32240856 hits, 0 misses

and buffer misses not incrementing with no buffers
ir-swaccess1#sh int g0/1 | i no buff
     385 packets input, 40711 bytes, 40 no buffer
ir-swaccess1#sh buff | i miss
     136288871 hits, 0 misses, 0 created
     92979420 hits, 40 misses, 112 trims, 112 created
     3183199 hits, 5279 misses, 6295 trims, 6310 created
     1967163 hits, 83 misses, 1440 trims, 1441 created
     0 hits, 0 misses, 0 trims, 0 created
     0 hits, 0 misses, 0 trims, 0 created
     0 hits, 0 misses, 0 trims, 0 created
     32248448 hits, 0 misses
ir-swaccess1#sh int g0/1 | i no buff
     891 packets input, 90329 bytes, 92 no buffer
ir-swaccess1#sh buff | i miss
     136289092 hits, 0 misses, 0 created
     92979462 hits, 40 misses, 112 trims, 112 created
     3183244 hits, 5279 misses, 6295 trims, 6310 created
     1967163 hits, 83 misses, 1440 trims, 1441 created
     0 hits, 0 misses, 0 trims, 0 created
     0 hits, 0 misses, 0 trims, 0 created
     0 hits, 0 misses, 0 trims, 0 created
     32248469 hits, 0 misses
ir-swaccess1#sh int g0/1 | i no buff
     1857 packets input, 206463 bytes, 299 no buffer
ir-swaccess1#sh buff | i miss
     136289318 hits, 0 misses, 0 created
     92979505 hits, 40 misses, 112 trims, 112 created
     3183287 hits, 5279 misses, 6295 trims, 6310 created
     1967163 hits, 83 misses, 1440 trims, 1441 created
     0 hits, 0 misses, 0 trims, 0 created
     0 hits, 0 misses, 0 trims, 0 created
     0 hits, 0 misses, 0 trims, 0 created
     32248495 hits, 0 misses
ir-swaccess1#