bpdu question stp

[Amafsha1]

Why would a switchport for a vlan only receive BPDUs and not send any, and why would another port for a different vlan only send BPDUs but never receive any?

[balaji.bandi]

Suggest to read below document have more explained : any question ask.

https://www.cisco.com/c/en/us/support/docs/lan-switching/spanning-tree-protocol/12013-17.html

BB

[Dennis Mink]

accessports. ie. ports that connect anything but something that could participate in spanning tree. i.e. phones, printers, laptop etc. do not have a reason to send BPDUs (because of port fast).

if you are not sending, but are receiving i can imagine you have something connected to an access port that does participate in spanning tree. typically if that happens and you have bpdu guard on that port, the port would go in err-diable. just saying

[rais]

Given RSTP is enabled, on every segment of a switched network there is a designated port and a root port. Designated port is the one responsbile [designated] to issue BPDUs on that segment. Root-ports usually are only receving BPDUs.

For example root switch would send out BPDUs while all other switches connected to Root would receive those BPDUs. A cease on BPDUs being sent out of Root switch would mean Root is dead and would trigger topology change.

HTH.