There are a few scenarios where LoopGuard would not be effective at detecting loops and/or unidirectional links. - can only be enabled on root & alternate ports. it CANNOT run on 'designated ports'. - ineffective at detecting a port that has been unidirectional since link-up.
Bridge Assurance (BA) is effective at mitigating those remaining scenarios that LoopGuard could not.
BA works because it turns STP into operating more like a routing protocol where BPDUs now go both ways on a given link verifying device health/awareness / lack of braindeadness. i.e. it turns STP from traditional "fail open" behavior to "fail closed".
[toc:faq]The ProblemOn traditional switches whenever we have a trunk
interface we use the VLAN tag to demultiplex the VLANs. The switch needs
to determine which MAC Address table to look in for a forwarding
decision. To do this we require the switch to do...
[toc:faq]Introduction:Netdr is a tool available on a RSP720, Sup720 or
Sup32 that allows one to capture packets on the RP or SP inband. The
netdr command can be used to capture both Tx and Rx packets in the
software switching path. This is not a substitut...
IntroductionOSPF, being a link-state protocol, allows for every router
in the network to know of every link and OSPF speaker in the entire
network. From this picture each router independently runs the Shortest
Path First (SPF) algorithm to determine the b...