Hello, Rene
if we suppose that we have 3 switch…we power on them…after booting,
the port of each switch connected each other goes into listening ,because they need to do an election…(in this 15 seconds a port is learning if it will be root port,designated port , or non designated port. Once understood, if it wiil be non designated goes into blocking state otherwise it’s going into learning and then forwarding).Now the switch network will be converged…If now I focus at the port in blocking state ,it receive BPDU by a peer designatet port,every 2 sec, and store that bpdu value (here now we can speak of the value of MaxAge-MessageAge…20 sec)…At one time the blocking port doesn’t receive bpdu from it’s designated switch, this one send a TCN to root bridge out it’s root-port, but my blocking port has to wait 20 second( MaxAge-messageAge) before going into listening state and can send out BPDu frame…Meanwhile this switch with this blocking port has to lower the aging time??? But I don’t understand who say to switch …lower the aging time