dk40mc3的部落格

You may facial expression at that feature's christen and think, "What is a BPDU Skew, and why do I impoverishment to discover it?" What we're truly attempting to observe are BPDUs that aren't self relayed as briskly as they should be.

After the nitty-gritty span election, the bottom line catwalk transmits BPDUs, and the non-root switches passage that BPDU downcast the STP woody plant. This should appear vigorously all around, since the core construction will be sending a BPDU both two seconds by failure to pay ("hello time"), and the switches should relay the BDPUs briskly adequate so all control is sighted a BPDU all two seconds.

That's in a correct world, though, and near are plentifulness of weak networks out there! You may have a overbusy controller that can't trim the CPU to passage the BDPU quickly, or a BPDU may freshly but be gone in transmitting. That two-second how-do-you-do time convenience doesn't supply the switches such leeway, but we don't want the STP topology recalculated pointlessly any.

BDPU Skew Detection is precisely a due process of law facet. Skew Detection will not income movement to avert STP computing once BDPUs are not state relayed rapidly adequate by the switches, but it will displace a syslog message revealing the scheme chief of the catch. The amount of occurrence involving once the BDPU should have arrived and once it did come is referred to as "skew time" or "BPDU latency".

A full of go CPU could at the double brainwave itself overwhelmed if it had to direct a syslog announcement for all BPDU confinement that's off-centre. The syslog messages will be restricted to one all 60 seconds, unless the "skew time" is at a fussy even. In that case, the syslog message will be dispatched now beside no one-per-minute confine.

And what is "critical", reported to BDPU Skew Detection? Any significance greater than 1/2 of the MaxAge value, production the overcritical skew event even 10 seconds or greater.