I do not understand the first part of your question, but regarding the loss of BPDU packets, the reason could be excessive collisions and subsequent packet loss, possibly because of a duplex mismatch. You might want to check this document, I think you need a CCO logon to view it:
Troubleshooting Spanning-Tree Protocol and Related Design Considerations
in a per vlan spanning tree environment, each spanning tree instance (vlan) will have a different root bridge mac address. If you find that the root bridge mac address is the same for a couple of vlans then these vlans have been bridged. This can result in a bridging loop. Unfortunately I do not understand the 2nd question.
the access switch is directly connected to a core switch, however, during the day, there were a few instance that the access switch loses the BPDU causes the access switch to max-time out. And the STP re-calculate again!...thanks!
[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...