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

[Tassos Chatzithomaoglou]

switch(config)#spanning-tree vlan 7 root primary ?
   diameter  Network diameter of this spanning tree
   <cr>

switch(config)#spanning-tree vlan 7 root primary diameter ?
   <2-7>  Maximum number of bridges between any two end nodes


--
Tassos

Tassos Chatzithomaoglou wrote on 21/05/2009 16:43:
> 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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> 
> 

-- 
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   Tassos Chatzithomaoglou
  Backbone & Access Networks
        FORTHnet S.A.
     <achatz at forthnet.gr>
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