Is this topology supported? DCI STP

[steve554365]

Requirements:

- DC1 N7K1 and N7K2

- DC2 N7K3 and N7K4

- DCI links N7K1-N7K3 and N7K2-N7K4

- Can't run vPC on DCI links because I need to run some point to point Layer 3 VLANs over those trunks for EIGRP peering. Don't have any more DCI links to move Layer 3 to, so have to work with just two links

- Don't pay attention to STP type, I could use RSTP+ per-vlan or MST, it doesn't matter.

Would this be supported? VLAN 100 lives in Data Center on the left, but I want to extend Layer 2 into Data Center on the right. Will STP actually block VLAN 100 on the vPC-peer link between N7K3 and N7K4?

[Peter Koltl]

It's a bad idea to connect DC's on Layer 2:

Layer-2 Network Is a Single Failure Domain

Layer-2 DCI and the infinite wisdom of acmqueue

Stretched Layer-2 Subnets – The Server Engineer Perspective

Busting Layer-2 Data Center Interconnect Myths

Whatever the server admins say, don't believe it's a must.

[steve554365]

LOL, sure, I'm going to take an advice for an opinionated cisco training instructor. Ivan is a smart guy, no question, but he does't deal with real world situations.

[Oleksandr Nesterov]

Hi Steve.

1. VPC peerlink is bever blocked by stp. If you will use your DCI linka for L2 and extend your vlan to the second DC - one of the DCI links will be suspended.

2. If you want to run L3 instead of L2 between DCI but want to extend vlans - you can use OTV. You'll keep L3 links and extend your L2 domain. OTV will isolate your STP and broadcasts, each you your DC will be protected if L2 issues will occur in another DC.

I suggest you to visit:

http://www.cisco.com/en/US/netsol/ns1153/index.html

HTH,

Alex