understanding fragments/crc errors

[diane09]

Group,

I am trying to understand some network issues, so I'm starting with the switches - (model 4200).  From the web interface of this switch, I check the status of the ports, I found fragments and errors that I don't understand on port 31:

History:

• 48 hours -  fragments - 3845, and total errors 4915



• 1 hour - fragments - 648, and total errors 936

When I check the port itself, the line that reads "Fragments(Rx)/Collisions(Tx) shows a total of 101093.

As you can tell by now, I'm not familiar with these totals, so from a professional to someone trying to learn, would this indicate, a bad nic card from the pc connected to the port, (don't laugh if I'm totally wrong on this....)

What would be your first thought when you see totals like this?

Thanks for any information.

Diane

[Fred_Mancen_1]

At first, I would check the duplex mode of these interfaces; it must be operating at full duplex mode. If it are operating at half duplex mode try to change the settings on both sides (switch port and NIC) to full duplex and check if the errors are still increasing.

At second, if there are no problems with the port settings, check the physical layer: NIC, cable, patch cords, patch panel and so on. Usually when a switch port shows problems with CRC, FCS, collisions and things like these there are errors at the physical layer or duplex settings.

Regards

[diane09]

Fred,

I did as you said, first checking the duplex mode, it was running "downrated" at 10FD, I reset it to Full Duplex, then the pc was not able to connect at all to the network.  Switched her line to another port, and now all seems fine, no more errors.  So one more question, when I'm checking the status of these switches, anytime I find these errors, I should be testing out these ports or the nic card - correct??  I should always stay ahead of errors, it is not normal to see these large counts on the "history" reports - agree?   And, I'm assuming this port is bad, I would not use this one again.

Many thanks for your post!!