I just noticed a big difference in numbers looking at the sent and receive counters for RSTP BPDUs.The port I'm looking at is a root port. I see a very less number of BPDUs sent against to BPDUs received. Is there a reason for this? I have 9 BPDUs sent but more than 50k BPDUs received.

  • I am sure, although not 100% that the received bpdus count for all bpdus from all other switches. So the root switch will receive bpdu from all other switches, as all others switches will receive bpdus from all other switches, hence why the receive counter is higher than the send counter – Gngogh Mar 15 '17 at 18:39
  • Okay. Once the root bridge is identified, the send counter stops at 9 BPDUs, whereas the receive counter keeps increasing. Why does this happen? I presume the root port should at least be sending the hello packets? Pleas explain. – Rakesh Nittur Mar 16 '17 at 13:20
  • Did any answer help you? if so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could provide and accept your own answer. – Ron Maupin Aug 7 '17 at 22:40

RSTP protocol which is now widely implemented is sending BPDUs only on designated ports. Those 9 are sent during convergence activity in the past.

  • So, once the convergence happens, it doesn't respond to any other BPDUs it is receiving? not even the hello packets to the other switches? – Rakesh Nittur Mar 16 '17 at 15:00
  • BPDUs are one-way, there's no answer mechanism. – Zac67 Jun 14 '17 at 18:19

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