cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
Announcements

1065
Views
0
Helpful
1
Replies
Sonugnair_2
Beginner

Double sided VPC/enhanced VPC and MST

Hello,

I have some doubts/clarifications regarding MST with VPC--

There are two N7K core switches and four N5K switches and eight N2K.

there will be double sided VPC between N5K and N7K.

there will be enhanced vpn between N5k and n2k.

N7Ks will be connected to fifteen 4500.

Each 4500 will be in a VPC with N7k.

Each 4500 is single homed to 15 catalyst edge switches

Assume MST needs be configured in this network.

1) On MST instance  - on N7K as per cisco design guide

2) Map all vlans (1-3967,4048-4093) in this instance N7K as per cisco design guide

3) No need to hard code root as peer switch command will be used

Now the concern that i have is regarding MSt configuration on all 4500.

1) 4500 number 1 may have vlans 2,3,4,5,6,7 and 4500 number 2 may have vlans 2,11,12,13,14,15,16

so can i just map all vlans to the single instance like instance 1 vlan 1-4094 on all catalysts 4500?

2) catalyst edge switches all run PVST+, i believe 4500 mst will interoperate with edge switch pvst+.

Is there any othe things that need tobe taken care of in this scenario?

Regards

1 REPLY 1
Jerry Ye
Cisco Employee

1) If you are using MST with single region, I don't see the point. It can be done with RPVST+ without any interop worries.

2) Same as 1.

3) This is not true, with peer-switch feature, it is a BP to hard code the N7K as STP root with the same priority value, otherwise, the smallest switch ID will be the root. In you case, most likely the oldest switch will become the root if you don't hard code it.

To your second set of questions:

1) Yes, you need to match all your region(s) with the same VLANs, otherwise, you will have MST inconsistency.

2) Yes.

HTH,

jerry