self-looping status in spanning tree

Unanswered Question
Aug 3rd, 2004


I show spanning tree in cisco 2950 switch and saw

the LBK state. then I viewed the detail and saw self-looping. Did anyone have relevant for LBK or self-looping informaiton.

best regards.


I have this problem too.
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aashish.c Tue, 08/03/2004 - 21:03


LBK state represents Loop-Back state. I would like to know , is it a uplink port or connected to any workstation. also in the logs, are there any messages for loopback state ?

If you have connected balun cable to this port then this can be in LBK mode, balun cable is a loopback cable.

kindly update.

mishao Wed, 08/04/2004 - 01:46


thanks. we just tested the broadcast-storm in 2950 and 3500XL/2900XL.

2950 blocked the traffic with LBK. but 3500/2900XL hang. So there was different processing for LBK between 2950 and 2900/3500.

best regards.


gpauwen Tue, 08/03/2004 - 21:14


A self-looping port is usually a port coupled to another port at the same bridge/switch. Can you check if your switch is physically configred like this ?




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