PPP Connection recieving collision errors...

Posted on 2009-07-07
Last Modified: 2012-05-07
Sorry if this is very vague.

We have a PPP connection between are campuses. The network is running but is recieving collision errors on both uplinks to the routers. The duplex and speed to set to auto, and gets half/10MB's. (There is a 10MB line between the buildings.)

When I hardcode the speed/duplex to half/10MB. The interfaces shut down and there is no activity at all.
Both routers are managed thru are ISP.

What is most likely the issue? Thanks!
Question by:wolf2008
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LVL 15

Expert Comment

by:Robert Sutton Jr
ID: 24794934
Are collision errors the only type of errors you're getting? If so, this is typically attributed to your simplex mismatch. When you get a mismatch on the network is will always kick back collision errors. Another indicator is when you "Hard-coded" them, both shut down. That tells you there is a mismatch in your settings between your provider's equipment and the campus equipment.
If this issue just started, you may have a problem w/ either the cabling or an interface that links the two buildings. You may want to contact your service provider and go over the link settings and speeds, etc with them to ensure they match accordingly.

Author Comment

ID: 24795271
ISP verify router configs as full and 10MB. However, when I hardcode that the port shuts down.
This is a brand new connection.
What is a simplex mismatch?

FastEthernet0/47 is up, line protocol is up (connected)
  Hardware is Fast Ethernet, address is 0022.0c4a.ea33 (bia 0022.0c4a.ea33)
  Description: (To Cisco 3400 Router port 1)
  MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec,
     reliability 255/255, txload 1/255, rxload 3/255
  Encapsulation ARPA, loopback not set
  Keepalive set (10 sec)
  Half-duplex, 10Mb/s, media type is 10/100BaseTX
  input flow-control is off, output flow-control is unsupported
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:00:00, output 00:00:01, 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 126000 bits/sec, 2 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     9986392 packets input, 8099764936 bytes, 0 no buffer
     Received 1296339 broadcasts (907560 multicasts)
     0 runts, 0 giants, 0 throttles
     1 input errors, 1 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 907561 multicast, 0 pause input
     0 input packets with dribble condition detected
     10582982 packets output, 5333970718 bytes, 0 underruns
     0 output errors, 368142 collisions, 1 interface resets
     0 babbles, 75356 late collision, 0 deferred
     0 lost carrier, 0 no carrier, 0 PAUSE output
     0 output buffer failures, 0 output buffers swapped out
LVL 15

Expert Comment

by:Robert Sutton Jr
ID: 24795341
Meaning Half/Full duplex. When one device is set to full and the  other is set to half, you will always get collsions. If this is a new "Link", there is obviously an issue here somewhere and it may be "physical".
IE: cabling, etc.

1) Try setting your fastethernet interfaces to Full Duplex, speed of 10Mb or 10000
2) Ensure you have good cabling in place and connections are "snug"
3) reset your interface counters and see if the errors increment.

Let us know.
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LVL 15

Accepted Solution

Robert Sutton Jr earned 500 total points
ID: 24795375
The reason I'm leaning towards a "cabling" issue is:
I see Input and CRC errors along w/ an interface reset.
Was this cable recently installed? How long is the run or length of the cable?

Author Comment

ID: 24795405
Ok. So the ISP confirmed Full & 10MB.

However, the switch uplink is set to (Auto for both) and detects Half & 10MB. Which is why we are having collisons.
When I go to hardcode the Full duplex the interface does down, & down. Even if I hardcode just 10MB the interface goes down, down.

So I'm correct in assuming that the ISP router config is setup to Duplex Auto, Speed Auto ?

The cable is a 5ft, Cat5e straight cable.
LVL 15

Expert Comment

by:Robert Sutton Jr
ID: 24795503
If they are hard coded to 10Mb Full Duplex, then thats what you should be connecting @....If you're setting your equipment to "Auto Negotiate" and they only connect @ 10Mb Half-duplex? Well, there's obviously an issue somewhere. How long are you giving your changes after hard-coding your uplink interface info to 10Mb Full before you have to change it back?

Author Comment

ID: 24795525
Yeah, we have connectivity with the auto/auto (half/10MB).

I gave it 2 mins. Both interfaces showed no connectivity. Should I wait longer?
LVL 15

Expert Comment

by:Robert Sutton Jr
ID: 24795606
I know it "should" come back faster than 2mins, but give it 5mins ...Also, how long is this cable run for the new "link"? Is the cabling new too or was this an existing cable?

Author Comment

ID: 24795921
Its a new fiber connection between the buildings. I doubt its a layer 1 issues as we do have connectivity between the buildings... It's just dirty connectivity.

Author Comment

ID: 24804522
The Cisco 3400 ME is a layer 3 switch and needs a cross-over connected to the Cisco 3560 switch. Hardcoded 10MB/Full no more collisions!!!

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