Input queue drops

[r.bosire]

I have a 7206VXR [ NPE-400] running 12.0(16)S8. I am experiecing rather abnormally high input queue drops on a transit network connected to one of the fast ethernets

This is affecting network performance as am seeing so many packet drops.

What could be wrong ?

Here is a sample output captured after 7 minutes of doing clear counters on the interface

gw1#show int fa4/1

FastEthernet4/1 is up, line protocol is up

Hardware is i82543 (Livengood), address is 0008.e260.0871 (bia 0008.e260.0871)

Internet address is 195.xx.xx.xx/26

MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec, rely 255/255, load 5/255

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 00:07:12

Queueing strategy: fifo

Output queue 0/40, 0 drops; input queue 0/75, 21754 drops

5 minute input rate 2966000 bits/sec, 709 packets/sec

5 minute output rate 2192000 bits/sec, 1089 packets/sec

297622 packets input, 158935506 bytes

Received 0 broadcasts, 0 runts, 0 giants, 36473 throttles

0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored

0 watchdog, 0 multicast

0 input packets with dribble condition detected

452773 packets output, 110146983 bytes, 0 underruns

0 output errors, 0 collisions, 0 interface resets

0 babbles, 0 late collision, 0 deferred

0 lost carrier, 0 no carrier

[rfroom]

What is the configuration of the interface? Is Fast-Swiching or CEF enabled. Is the router having to process switch every packet for some reason.

Post the configuration of the interface.

A simple way to correct *may* be to increase the size of the input queue in the case of bursty traffic like IPX.

[r.bosire]

below is the interface config, increase of the input queue depth , doesnt help either

interface FastEthernet4/1

ip address 195.202.69.60 255.255.255.192

no ip directed-broadcast

speed 100

full-duplex

no cdp enable

!

gw1#show int fa4/1

FastEthernet4/1 is up, line protocol is up

Hardware is i82543 (Livengood), address is 0008.e260.0871 (bia 0008.e260.0871)

Internet address is 195.xx.xx.xx/26

MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec, rely 255/255, load 7/255

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 00:00:21

Queueing strategy: fifo

Output queue 0/40, 0 drops; input queue 0/200, 1732 drops

5 minute input rate 2461000 bits/sec, 747 packets/sec

5 minute output rate 2930000 bits/sec, 1258 packets/sec

16405 packets input, 6879085 bytes

Received 0 broadcasts, 0 runts, 0 giants, 2739 throttles

0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored

0 watchdog, 0 multicast

0 input packets with dribble condition detected

27774 packets output, 7826858 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

[gordons]

You might try changing your queuing from fifo to weighted-fair.

That has helped solve some packet drops for me.

Gordon

[r.bosire]

Still getting the drops

gw1#show int fa4/1

FastEthernet4/1 is up, line protocol is up

Hardware is i82543 (Livengood), address is 0008.e260.0871 (bia 0008.e260.0871)

Internet address is 195.xx.xx.xx/26

MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec, rely 255/255, load 6/255

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 00:01:53

Input queue: 0/75/4288 (size/max/drops); Total output drops: 0

Queueing strategy: weighted fair

Output queue: 0/1000/64/0 (size/max total/threshold/drops)

Conversations 0/2/256 (active/max active/max total)

Reserved Conversations 0/0 (allocated/max allocated)

5 minute input rate 2808000 bits/sec, 754 packets/sec

5 minute output rate 2581000 bits/sec, 1160 packets/sec

69379 packets input, 31527226 bytes

Received 0 broadcasts, 0 runts, 0 giants, 7158 throttles

0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored

0 watchdog, 0 multicast

0 input packets with dribble condition detected

111324 packets output, 29039822 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

[nuno.morais]

Hi.

I don't think that changing the queuing will solve input queue drops!

What's your CPU load?

Rgds.

NM