Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

Loop Guard Blocking

I need to preface this with i am compleatly new to Cisco equipment so for give and ignorance expressed.

I have a 3560G-48TS I have port 48 connected to a Layer 2 switch and the port seems to get shut off sevral times a day with this error message:

Description: Loop guard blocking port GigabitEthernet0/48 on VLAN0001.

Explanation:  The spanning tree message age timer has expired because and no BPDUs were"  "received from the designated bridge. Since this condition could be caused"  "by an unidirectional link failure, the interface is put into blocking"  "state and marked as loop guard inconsistent in order to prevent possible"  "loops from being created 

Recommended Action:  Issue the <CmdBold>show spanning-tree inconsistentports<noCmdBold> "  "command to review the list of interfaces with loop guard inconsistencies."  "Determine why devices connected to the listed ports are not sending BPDUs."  "One reason could be that they do not run the spanning tree protocol; in"  "this case you should disable loopguard in the inconsistent interface/s or"  "start the spanning tree protocol on the other side of the link/s.depending"  "on the context".  "Another reason could be a failure in the cable: if the link has a failure"  "that makes it unidirectional (you can transmit but you can not receive) it"  "should be replaced with a proper cable. 

Type: SPANTREE-2-LOOPGUARD_BLOCK

I have been doing a lot of searching and i have not figured out what to do about it yet, any help would be aprecaited.

Also using the CNA software when i look at System messages, they are not time stamped with the correct time zone time even though i have verified that the time on the switch is correct and it is also point at my networks NTP server for its time.

Everyone's tags (4)
295
Views
0
Helpful
0
Replies