10 Replies Latest reply: May 9, 2012 6:18 PM by klaus RSS

    STP: Which ports send/receive BPDUs?


      I have been having issues with the granular concepts of STP.  In particular, loopguard.  I think I would understand its full potential and functionality if I understood which ports send and receive BPDUs.  According to my CCNP:  Implementing Cisco IP Switched Networks book, which has soooo many errors that it has lost its integrity, ports in the listening state send and receive BPDUs.  Forwarding ports do the same. Blocking ports only receive BPDUs?


      When I verify this on my 3550s, it does appear to be true.  I forgot exactly which ports where sending or receiving BPDUs, but it seems that a port is almost always sending OR receiving, never both.


      Can someone please verify which ports send and/or receive BPDUs and if its port state matters?  Thanks a million!