Solved: rstp and hello bpdu

sarahr202 · ‎04-21-2012

Hi everybody.

I have been reading this book for my switch exam which is full of errors thus I find the book personally very unreliable. For example, my book says hello bpdu are sent out every port in rstp regardless if the switch receives a bpdu from root bridge or not. I just want to confirm that. I have been searching for any document corroborating the book statement.

Could anyone please clearfy this ?

thanks and have a great weekend

kamran_Roostaee · ‎04-21-2012

Dear Sarahr

in STP non-root bridge only generates BPDUs when it receives one on the root port but in RSTP non-root bridge sends a BPDU with its current information every hello-time seconds (2 by default), even if it does not receive any from the root bridge so in RSTP If a bridge fails to receive BPDUs from a neighbor, it suppose that the connection to that neighbor is lost but in STP if bridge fails to recieve BPDUs from a neighbor, problem might have been anywhere on the path to the root.

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kamran_Roostaee · ‎04-21-2012

Dear Sarahr

in STP non-root bridge only generates BPDUs when it receives one on the root port but in RSTP non-root bridge sends a BPDU with its current information every hello-time seconds (2 by default), even if it does not receive any from the root bridge so in RSTP If a bridge fails to receive BPDUs from a neighbor, it suppose that the connection to that neighbor is lost but in STP if bridge fails to recieve BPDUs from a neighbor, problem might have been anywhere on the path to the root.