[c-nsp] Limits of STP/RSTP/REP?

[Tassos Chatzithomaoglou]

I had the impression that STP diameter defined the max number of bridges between 2 points.
And the recommended value by the IEEE was 7 (using default timers).

--
Tassos

?????? ???????? wrote on 21/05/2009 12:25:
>> Definitely not more than 20 in a ring.  As far as I know, IOS limits
>> the value of max-hops to 20.  This means you can't have a BPDU
>> traverse more than 20 hops without being thrown away.  If one pair of
>> switches in the ring experienced a total cut, your network would have
>> a diameter of 20, end to end.
> 
> this is STP limitation: MaxAge is by default 20 hops.
> for IOS, you can change this value:
> 
> Switch(config)#spanning-tree vlan 1 max-age ?
>   <6-40>  maximum number of seconds the information in a BPDU is valid
> or for MST
> Switch(config)#spanning-tree mst max-age ?
>   <6-40>  maximum number of seconds the information in a BPDU is valid
> 
> value 40 is maximum bpdu hopcount for 3560 switch, for other models
> there can be other upper limit.
> 
> --
> wbr
> sergey khalavchuk
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