2950 Buffers

[duncan.goodfellow]

I have an issue with poor response times to my 2950 switches. Is this a buffer issue.

#sh buffers

Buffer elements:

498 in free list (500 max allowed)

15748070 hits, 0 misses, 0 created

Public buffer pools:

Small buffers, 104 bytes (total 60, permanent 25, peak 216 @ 7w0d):

58 in free list (20 min, 60 max allowed)

332486543 hits, 41248124 misses, 38587109 trims, 38587144 created

6638186 failures (0 no memory)

Middle buffers, 600 bytes (total 38, permanent 15, peak 63 @ 7w0d):

36 in free list (10 min, 30 max allowed)

50877799 hits, 705738 misses, 627856 trims, 627879 created

147902 failures (0 no memory)

Big buffers, 1524 bytes (total 11, permanent 5, peak 28 @ 7w0d):

11 in free list (5 min, 10 max allowed)

4265500 hits, 3408314 misses, 1148631 trims, 1148637 created

2399839 failures (0 no memory)

VeryBig buffers, 4520 bytes (total 10, permanent 0, peak 24 @ 7w0d):

10 in free list (0 min, 10 max allowed)

2461111 hits, 598383 misses, 124669 trims, 124679 created

597711 failures (0 no memory)

Large buffers, 5024 bytes (total 3, permanent 0, peak 7 @ 7w0d):

3 in free list (0 min, 5 max allowed)

509954 hits, 87757 misses, 15137 trims, 15140 created

87757 failures (0 no memory)

Huge buffers, 18024 bytes (total 2, permanent 0, peak 4 @ 7w0d):

2 in free list (0 min, 2 max allowed)

30240 hits, 57517 misses, 11160 trims, 11162 created

57517 failures (0 no memory)

Interface buffer pools:

Calhoun Packet Receive Pool buffers, 1560 bytes (total 512, permanent 512):

442 in free list (0 min, 512 max allowed)

510963830 hits, 0 misses

[mheusinger]

Hello,

With "poor response times to my 2950" you mean ping and telnet issues when accessing the switch?

Well let us first have a look at

Small buffers, 104 bytes (total 60, permanent 25, peak 216 @ 7w0d):

58 in free list (20 min, 60 max allowed)

332486543 hits, 41248124 misses, 38587109 trims, 38587144 created

6638186 failures (0 no memory)

There are misses, trims and failures. Their meaning is described in

http://www.cisco.com/en/US/products/sw/iosswrel/ps5187/products_command_reference_chapter09186a008017d03c.html#wp1062144

So according to this I would conclude your device is under some load and you might have to watch out for memory issues. So far however there is "nothing wrong".

The poor response of the switch however can be explained, in case the system is under load because f.e. ICMP is considered low priority compared to handling traffic through the switch.

This can mean that the reponse times are sometimes a couple of 10 ms for ICMP replies.

Hope this helps! Please rate all posts

Martin

P.S.: just out of curiosity: the command reference for the 2950 does not mention the command "show buffers" - which IOS is running in the switch?

[duncan.goodfellow]

Yes, I do mean ping & telnet responses, sometimes response times are over 100ms. The IOS on the Cat2950 Switch is 12.1(22)EA4

CPU peaks at 27% Memory Used peaks at 80%

Ciscoworks DFM also reports 'invalid snmp response' alarm as well.