Re: [nsp] 7100 and small packets

From: George Robbins (grr@shandakor.tharsis.com)
Date: Wed Aug 01 2001 - 10:07:09 EDT


I'm not sure that the CPU loading is your worst problem.

> Output queue 0/40, 0 drops; input queue 8/75, 1478 drops

The load realated packet loss is .0015% though it will be worse
at peak loading. Since this is input drops, it means packets
coming in more quickly than old ones can be sent out.

> 208760 input errors, 208760 CRC, 0 frame, 0 overrun, 0 ignored
> 0 watchdog, 0 multicast
> 103898 input packets with dribble condition detected

These suggest that you have an ethernet problem, possibly wiring
or perhaps a switch that's not 100% compatible as far as switching
modes or flow control, or is having loading problems on it's own.

In any case, you want to review the setting and error statistics
for the other end of the link.

As far as CPU utilization, if you're not using "ip route cache cef"
plus "ip route-cache same-interface" do it.

Generally if the router has lots of routes, as in an internet gateway,
you need to be using CEF, if it has only a few such as an internal
corporate network, then flow or normal (fast) cache will work about
as well.

                                                George

> Date: Wed, 1 Aug 2001 14:44:14 +0100 (BST)
> From: Jean-Christophe Varaillon <jcv@vbc.net>
> Subject: [nsp] 7100 and small packets
>
> Hi,
>
> On a 100 M Full-duplex interface of a Cisco 7100, I receive some very
> small packet due to Games application and/or VOIP traffic.
>
> Because of this I have an abnormal CPU utilization rate.
> Therefore, I have some packet loss when I run somes ping.
>
> kg6.uk0#sho int fa0/0
> FastEthernet0/0 is up, line protocol is up
> Hardware is DEC21140A, address is 0003.3184.8800 (bia 0003.3184.8800)
> Internet address is 192.168.0.21/25
> MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,
> reliability 255/255, txload 11/255, rxload 13/255
> Encapsulation ARPA, loopback not set
> Keepalive set (10 sec)
> Full-duplex, 100Mb/s, 100BaseTX/FX
> ARP type: ARPA, ARP Timeout 04:00:00
> Last input 00:00:00, output 00:00:00, output hang never
> Last clearing of "show interface" counters 22:17:20
> Queueing strategy: fifo
> Output queue 0/40, 0 drops; input queue 8/75, 1478 drops
> 5 minute input rate 5453000 bits/sec, 1975 packets/sec
> 5 minute output rate 4342000 bits/sec, 1983 packets/sec
> 95383572 packets input, 1399376380 bytes
> Received 162215 broadcasts, 0 runts, 294 giants, 1478 throttles
> 208760 input errors, 208760 CRC, 0 frame, 0 overrun, 0 ignored
> 0 watchdog, 0 multicast
> 103898 input packets with dribble condition detected
> 95244094 packets output, 1975945187 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 output buffer failures, 0 output buffers swapped out
>
>
> I would like to know what alternative I have to solve this trouble.
>
> Regards,
> Jean-Christophe.
>
>
>



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