collisions and errors in the network monitor report

[richardfu]

One of the remote offices connects to my office through Bell 10M ATM network. I found many collisions and errors in the network monitor report. I checked the wan port of the remote office switch. Many collision and errors happened in the port. Because other offices use the same ATM link from Bell ATM switch/router to my office，Other offices are OK.

So, I can say the link from my office to Bell Internet router is ok. The problem happened either in Bell network or from the bell network to the remote office. Bell was called to check their link. But they replied they couldn’t find any collision. I asked people to change the wan port/cable in the switch in remote office. And reboot the switch in remote office and Bell switch in the remote office too. But no luck. The errors in the network report increased.

Any suggestion how to deal with the problem?

[smalkeric]

Check the CRC field. The presence of many CRC errors, but not many collisions, indicates excessive noise. If the number of errors is too high, check the cables for damage. If you are using UTP cable, make sure you are using category 5 cables and not another type, such as category 3.

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Note Errors and the input and output difference should not exceed 0.5 to 2.0 percent of traffic on the interface.

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Check the collisions fields. These numbers indicate packet collisions, and these numbers should be very low. The total number of collisions with respect to the total number of output packets should be approximately 0.1 percent or less.

Check the late collisions fields. Late collisions should never occur in a properly designed Ethernet network. They usually occur when Ethernet cables are too long or when there are too many repeaters in the network.

For more information please you refer the below link for troubleshooting tips and make a note on the left column of the link having more troubleshooting link on ATM :

http://www.cisco.com/en/US/products/hw/modules/ps2033/products_tech_note09186a00800d76e5.shtml

http://www.cisco.com/en/US/products/hw/switches/ps718/prod_troubleshooting_guide_chapter09186a00800f019e.html

[richardfu]

Thanks a lot!