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837 Ethernet Issue

Hi Guys,

I hope someone will ahve an answer for this. I have an 837 installed on a customers site. This is a DMVPN spoke back to a hub site (C1841). This has happened this router before.

All of a sudden yesterday the router started losing packets between the Switch (3com superstack) and it's ethernet ports. Also any packets that got through had a latency of anywhere between 6ms and 4000ms. Unreal.

I changed ethernet ports on the 837 and reset the switch. last thing i did was shutdown that e0 on the 837 and brought it back up. hey presto it went back to normal operation. I do fear that this will ahppen again. Also i noticed over 100 input errors on e0 in a 6 hour period.

Any Ideas



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Re: 837 Ethernet Issue

Hello Stephen,

input errors are usually caused by duplex and/or speed mismatches, or by cabling or NIC errors. If possible, exchange the cable between the Cisco and the 3Com. You also might want to try and isolate individual machines connected to the 3COM, possibly one of them is causing the problem. If you turn the machines on one by one, you should be able to see which one causes the errors. If you find the machine, check the NIC and exchange it, or run an anti-spyware program such as Spybot or Adaware on that machine, since it might also be infected...



Super Bronze

Re: 837 Ethernet Issue


Are your speed/duplex set on the router and switch crrectly?

The E0 interface on those routers is virtual (set IP etc on this) and there are four FE interfaces that are the physical interfaces.

If you are using port 1, set it to 10Full and set the switch port it attaches to to 100Full. See if this stops your errors accumulating...


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