Cisco Router 3640 Seeing collisions and dropped packets...

Lastnight, I tried to rule out each switch to make sure they weren't problematic. Didn't see much of a change taking them out of the mix. Collisions and spikes every which way.

To save anyone who might respond some time. I did replace patch cables, even elliminated all but maybe 3 machines on the network as far as a possibile points of collision.

Here are the two ether configs:

Ethernet1/0 is up, line protocol is up
  Hardware is AmdP2, address is 00b0.xxxx.e111 (bia 00b0.xxxx.e111)
  Internet address is 66.xxx.xxx.126/25
  MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec,
     reliability 255/255, txload 7/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive set (10 sec)
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:00:02, output 00:00:00, output hang never
  Last clearing of "show interface" counters 1d09h
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 2000 bits/sec, 2 packets/sec
  5 minute output rate 309000 bits/sec, 300 packets/sec
     742033 packets input, 188881301 bytes, 0 no buffer
     Received 2730 broadcasts, 0 runts, 0 giants, 0 throttles
     28767 input errors, 28767 CRC, 14363 frame, 0 overrun, 0 ignored
     0 input packets with dribble condition detected
     27154290 packets output, 3649239068 bytes, 0 underruns
     400 output errors, 7060 collisions, 2 interface resets
     0 babbles, 0 late collision, 4069 deferred
     400 lost carrier, 0 no carrier
     0 output buffer failures, 0 output buffers swapped out


Ethernet2/0 is up, line protocol is up
  Hardware is AmdP2, address is 00b0.xxxx.e121 (bia 00b0.xxxx.e121)
  Internet address is 66.xxx.xxx.254/25
  MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec,
     reliability 255/255, txload 1/255, rxload 97/255
  Encapsulation ARPA, loopback not set
  Keepalive set (10 sec)
  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 never
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 3835000 bits/sec, 369 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     7680296 packets input, 1122703180 bytes, 0 no buffer
     Received 2427 broadcasts, 0 runts, 0 giants, 0 throttles
     3 input errors, 1 CRC, 1 frame, 0 overrun, 2 ignored
     0 input packets with dribble condition detected
     222161 packets output, 49623925 bytes, 0 underruns
     4627 output errors, 73289 collisions, 3 interface resets
     0 babbles, 0 late collision, 14273 deferred
     4466 lost carrier, 0 no carrier
     0 output buffer failures, 0 output buffers swapped out

>set both ethernet interfaces to half duplex
In any network using half-duplex, collisions, retransmits and dropped packets are all very expected behavior. These are all designed into the Collision Detection/Avoidance mechanisms of Ethernet.
The more traffic, the more collisions and dropped packets.
TCP/IP has mechanisms to recover from the dropped packets.

As long as you don't have a high percentage of collisions, then it appears that everything is working as designed.

Looking back at your previous post, it does not appear that you had a duplex-mismatch issue to start with:

  10013 input errors, 10013 CRC, 5043 frame, 0 overrun, 0 ignored  <== typically these point to layer 1 defects (bad cables)
     0 input packets with dribble condition detected
     9460395 packets output, 1225723073 bytes, 0 underruns
     94 output errors, 0 collisions, 0 interface resets   <=== collisions would normally increase if you had duplex issues

Did you replace the patch cables as JFrederick suggested?

https://www.experts-exchange.com/questions/21168787/Cisco-Router-Model-3640-CRC-Frame-Errors-on-Ethernet-Int-major-packet-loss.html

This is my prior post so you can view what was discussed.

Best Regards

<8-}
I guess we posted at the same time!

You are suffering 32% collision rate  (73289 collisions / 222161 packets)
This is unacceptible..

plus --    4466 lost carrier, 0 no carrier

Highly suggest that you put the interface back to auto duplex...

Just another suggestion (unrelated to the error problem):
  > ip access-group 110 in
  > ip access-group 110 out

It is highly discouraged to use the same acl in both directions....

>To save anyone who might respond some time. I did replace patch cables, even elliminated all but maybe 3 machines on the network as far as a possibile points of collision.

If you look at the ether configs I posted today, there are many more collisions then what was seen yesterday with those interfaces set to half duplex but a lot less dropped packets.

When set to full duplex (both ethernet interfaces), I don't see the collisions or CRC erros but I experience 60% loss on the second subnet (Ether2/0). When set to half duplex, I am seeing a lot less loss but am still experiencing enough of it that I have to take notice. We don't want to run at half duplex period but we were seeing so much loss at full duplex, this was a temporary solution. We have 6 T1's bonded right now, so until we figure out what is causing this, we are only going to see maybe 4megs of that bw which is going to throttle us. I did not know before yesterdays post that that so many collisions were to be expected in the current environment. I haven't seen nearly so many in others that I maintain so it did strike me as odd. I am still learning though.

I am not saying this is a duplexing issue, I was just stating what I was assuming after seeing it improve once setting it to half duplex yesterday.

I don't know what is wrong.

I don't have an option to set to auto. I can set to half or full unless I am missing something.

>Just another suggestion (unrelated to the error problem):
  > ip access-group 110 in
  > ip access-group 110 out

I am not at all arguing but can you tell me why?

I'd just like to know, probably a stupid question but I'll ask it anyway.

Thanks!

Yeah, it makes sense what you had to say about the acl's. The way I have it configured defeats the purpose.

I did set it to auto duplex using the syntax your provided but I am still seeing collisions...Any other suggestions?

Thanks for your responses!

>but I am still seeing collisions...
If you see collisions, then most likely the interfaces have negotiated to half-duplex. That's OK as long as the percentage is not as high as it was..

Do you think installing a managed switch that I can force to full duplex, I will be able to run the router in full without the collisions?

Absolutely!

Thanks for your time. There may be more to it but I have learned something through this process and you have helped me to improve on it...So I will accept...

Thanks a lot man.

Glad to help!