[c-nsp] Migration to Rapid-PVST

Rolf Mendelsohn rolf-web at cyberops.biz
Sat May 13 09:09:38 EDT 2006


Hi Robert,

We have 122 VLAN's running across 2 x 3550's and 2 x C2950's in MST with 
mainly wireless trunk ports.

The implementation is the same.

Make sure you try and block all weird stuf at customer ports - e.g.

 switchport mode access
 no cdp enable
 spanning-tree portfast
 spanning-tree bpdufilter enable
 spanning-tree bpduguard enable
 spanning-tree guard none
end

Also bear in mind that the 2950's / 2950G can only handle 250 VLAN's, the next 
cheapest switch which handles more is the 2400-ME (1005).

cheers
/rolf

On Saturday 13 May 2006 13:50, Robert Hass wrote:
> On Sat, 13 May 2006, Per Carlson wrote:
> >If you are going to change the STP, why not take the full step to to
> >MST? When using "desktop switches" in the network, you will sooner or
> >later run into the STP instances limitation (128 instances). By
> >running MST, this will no longer be an issue.
>
> Thanks for the tip. It could be very good idea for future - as we're
> adding 3-10 VLANs each month.
>
> Basing on my first post with network diagram how many instances you
> recommend to have ? And which switches should be root-bridges for these
> instances.
>
> >- how the edge ports (customer ports) are configured (are those
> >  running STP or not)
>
> We have configured bpdu-filter and SPT portfast at customers ports.
> Most of customers using static routing, so We're terminating them on
> both our 7304 routers providing redundancy with HSRP.
>
> >- the number of MAC-addresses that needs to be flooded and
> >  relearned
>
> Most of VLANs carring up to 2-6 MACs. I worst case it will be 50 VLANs
> * 6 MACs = 300 MACs.
>
> >Be aware that there are two different MST implementations in IOS,
> >one pre-standard and one standard. As far as I have seen, those
> >will interoperate without any problems. But running the same type
> >in the whole network is probably a Good Thing (tm).
>
> I have 12.2(25)SED and 12.2(25)SEE on 3550/3560/3750 and 12.1(22)EA7 on
> 2950. Is MST implementation in 12.1(22)EA7 is same that in
> 12.2(25)SE{D/E} ?
>
> Robert
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-- 
Rolf Mendelsohn
ITA/MAXNET
+244 923524981


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