Cisco Loop Guard Confusion
I have problems understanding loopguard. Firstly why would you put loop guard on a root port which is a forwarding state anyway??
Secondly when we put loop guard on what happens when when the neighboring switch legitmately goes down and the obviously the blocking port
stops recieving bpdu's from the switch that has gone down it then it goes into the loop inconsistent state rather than into a forwarding state for the segment does it not
take away the failover functionality of spanning tree requiring manual intervention??
Secondly when we put loop guard on what happens when when the neighboring switch legitmately goes down and the obviously the blocking port
stops recieving bpdu's from the switch that has gone down it then it goes into the loop inconsistent state rather than into a forwarding state for the segment does it not
take away the failover functionality of spanning tree requiring manual intervention??
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thaks for the replies
mike that explains the link issue what about why do we put loop guard on root ports which are forwarding anyway
jbrmiller i think you may confusing loop guard with udld that is the protocol that is not related to spanning tree and sends keepalives loop guard is part of spanning tree tools and monitors bpdus as far as my study so far says anyway
bpdu guard is for making sure if you mistakenly connect a switch to portfast enabled port it does not go straight away into forwarding state bypassing listening learning etc possible creating a loop it error disables on reciept of bpdu if enabled on interface
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>The idea is to put it on all ports facing the root switch.
I mean, all ports with a potential path to the root switch, whether blocking or forwarding.
I mean, all ports with a potential path to the root switch, whether blocking or forwarding.
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Loopguard sends keepalives through all ports on the switch, and this frames are ignored by all neighborging switches, and are not forwarded. But, if a loop is created, and the switch receives his own keepalive in any port, the port is err-disabled.
the protocol that's related to spanning tree is bpduguard, and is intented for other purposes.