|
Home > Archive > CCNP > June 2001 > FCS Errors
You are viewing an archived Text-only version of the thread.
To view this thread in it's original format and/or if you want to reply to
this thread please [click here]
|
|
| nuttde 2001-06-22, 10:20 am |
| I have a server directly attached (10feet) to a cat 5000 switch in our computer room..I continue to receive FCS errors even after replacing the cable,NIC card, moved to a different switch port and moved the server across the room . This is a manufacturing environment, I'm thinking it may be environmental.
Any ideas???? | |
| BlueBaron 2001-06-22, 1:29 pm |
| If you're running half-duplex between them, then you can expect an error to data ratio of roughly 1%.
If you're running full duplex, make sure the other side is too. Also, ensure that the switch is NOT operating in "Auto" mode. Hard code the duplex setting if you can, Cisco doesn't play well with Auto . . . .
What is the percentage of errors to data that you're currently seeing? | |
| strikeattack 2001-06-22, 3:04 pm |
| I agree with Blue Baron. The first thing to do is set BOTH SIDES to 100Mbit Full Duplex (assuming they can both support it of course). Also frame errors under 3% on a shared bus are normal. I remember reading that it is normal to have 2-3% of errors on a shared line, resulting in FCS errors, runts, giants, framents, etc... I will try and find the link if I can. You should not have any errors in full-duplex mode, because the only collision domains are one-way and a node will not collide with itself; unless of course, the NIC is malfunctioning.
If you cannot resolve the issue, try setting up a mirror port that mirrors the server port and sniff the traffic with a good sniffer.
If you are unable to do that, try setting the server up into a peer-to-peer topology with a crossover cable with whomever he is talking to.
If none of this works, try reinstalling the logical NIC adapter, and if that doesn't work, the layer-3 protocol (IP probably), although this is starting to get very "iffy."
Also, if the problem was environmental, there is a good chance other nodes in that area would be exhibiting similar symptoms. Check those.
Remember, anything outside of the 64-1518 byte range is an invalid frame.
Your best bet is locking down both sides and using a sniffer to sniff the mirror port. I hope this helps. | |
|
|
| Core Smore 2001-06-22, 4:53 pm |
| Are your network cable close to any florescent lights? If you are in a manufacturing environment try to keep it away from any electromagnetic devices. Thats some of the things environmental that I can think of that can affect it. The suggestions made earlier is most likely the solution that you are looking for. | |
| strikeattack 2001-06-23, 7:47 am |
| BB,
I agree with you, however if the NIC is malfunctioning, there is NO WAY to know what it is going to do. CSMA/CD IS disabled when operating in full-duplex mode, but unpredictable things can happen if the NIC is malfunctioning. This includes the CSMA/CD circuit failing to de-activate in full-duplex mode. That was my only point. I'll try to be clearer next time.
I also like to say nothing is impossible... For example, we had a tow motor that ran over CAT5 that the process engineers had laid on the ground (not my work). The cord was partially severed and the TX/RX pairs were shorting out (collisions). |
|
|
|
|