MSTP query

[Davit2005]

Hi All,

New to MSTP , although done my CCNA over 13 years ago but not had much in the field hands on yet.

 

We run a huge/complex estate and using MSTP with currently 3 MST instances on our aggregation/core switches and we now need to add some vlans to the instances.

 

If we create a new instance, thinking of creating at least another 2 and using some unused vlan id's, do we only have to wait for the added instance to converge or does this still effect all instances??

 

Cheers for any help.

[FN-GM]

What switches do you have?

 

Can you rephrase that question please? I don't understand what you mean.

 

Thanks

[FN-GM]

Re read a few times. If I have understood the question, when you create a new instance of MSTP and use it for new VLANs that are new it shouldn't impact any existing instances. They sit as separate instances.

 

Am I right in thinking you're all Cisco? If so I would look at PVST or rapid-psvt. It does what MSTP does but:

 

1. Configuration is automatic once you enable PVST spanning tree mode. The switch will sort its instances out.

2. You have 2 instance per VLAN so more fault tolerance.

3. Great of resources. Your switch will be able to handle an instance for each VLAN. Infact i believe its better on resources than MSTP.

Edited January 31, 2017 by FN-GM

[Davit2005]

Re read a few times. If I have understood the question, when you create a new instance of MSTP and use it for new VLANs that are new it shouldn't impact any existing instances. They sit as separate instances.

 

Yes this is what we were thinking as well.

 

Funny I was expecting a response from you , I wish I put money on it.

 

We have all HP's with a mixture of 5400's and 8200's at the core. 7 switches total have been configured with MST by looks of it. Or should I say have some MST config present i.e. additional instances where you can see vlans assigned to the instances.

 

3 MST instances currently and we need for a specific project for 128 small subnets/vlans so maybe thinking another 2/4 instances. I think we can create quite a few instances but unsure of the consequences of adding too many at the mo. The small subnets will be routed at the firewall for security and manageability as they need to be kept isolated from the rest of the network but may need to be accessed by certain people on it so do not want to have hassle of complicated ACL's on switches.

 

Thanks again.

Edited January 31, 2017 by Davit2005

[Davit2005]

Ping'd

 

A bit more info on this. We have 4 core switches, 3 Instances with each of the core being root for one instance and a switch acting as root for none.

 

Can we have a switch be root for more than one instance??