[c-nsp] Maximum spannig tree instances

[Christopher E. Brown]

Gert Doering wrote:
> Hi,
> 
> On Tue, Jul 14, 2009 at 08:58:53PM -0800, Christopher E. Brown wrote:
>> Come on guys, study the proto a little before going off.
> 
> We did...
> 
>> In order for MST to work all members of an MST domain *MUST* agree on
>> the VLAN -> MST group mapping.
>>
>> If you change the mapping it must update across all members of the domain.
>>
>> YOU ARE REDEFINING THE STP TOPOLOGY
> 
> ... and that's just not workable for Real Networks that undergo daily 
> changes, and have wildly differing VLAN topologies.  Especially the latter
> one ("due to traffic reasons, we have to move the STP active link for
> VLAN 714 to *this* trunk").
> 
> gert

Exactly, MST only applies when you can group the vlans _long term_, and
this only happens when individual VLANs are a small percentage of
traffic.  The traffic routing ability is linited to the _group_.


If this does not apply, the a per vlan variant is needed.


I use both, complex large flow per vlan is rapid per vlan, bulk
distribution domains are MST with pre-assigned use per group.