LAN Extension Curcuit generating Undersize errors

[mgarr01]

We have a 10Mb LAN Extension Circuit connected to a 2950-24T, which in turn is connected to a 3550-12T.

When doing a SH INT COUNT ERR on the 3550 the UNDERSIZE counter is climbing on the port that the 2950 is connected. When doing the same on the 2950 the UNDERZIZE counter is zero.

To rule out the port on the 2950 we have moved the LAN Extension Circuit to different ports, but the UNDERSIZE counter on the 3550 still climbs.

To rule out the 2950 itself we have move the LAN Extension Circuit connection to another 2950, connected to a different port on the 3550. The UNDERSIZE counter climbs on the new port.

Any ideas???

Cheers

Mark

[ebreniz]

Is the Lan extension longer than the permissible length.(100 meters), the cable used between them. What is the duplex used between the switches , if you have a mismatch in duplex the same effect can happen. If possible make it 100Mbps/FULL duplex, check if you have any VLANs. Then trunking should be done between them. For more information refer this link.

http://www.cisco.com/en/US/tech/tk389/tk214/technologies_tech_note09186a008009446d.shtml