Multiple vPC domains on a single Nexus 7000

[Patrick Colbeck]

Is this possible ?

I have a customer with three rooms where teh access layer aggregation switches are run back to.

Access Switch Stack A -> room 1 + room 2

Access Switch Stack B -> room 2 + room 3

Is it possible to have three Nexus 7000s ie one in each room (1,2 and 3) and have them setup like this:

Nexus 7000#1     vPC domain 1

Nexus 7000#2     vPC domain 1 + vPC domain 2

Nexus 7000#3     vPC domain 2

Thus gving all access switch stacks redundant links to the core withouit spanning tree.

I know its not ideal but its a campus site and thats how the existing fibre runs go.

[nkarpysh]

Hi,

You will not be able to configure two peer-links to Nexus 7000#1 and 7000#3 on 7000#2. So this is not possible. Why don't you want to connect both stack to a single pair of Nexus switches?

Nik

[darren.g]

pcolbeck wrote:
Is this possible ?
I have a customer with three rooms where teh access layer aggregation switches are run back to.
Access Switch Stack A -> room 1 + room 2
Access Switch Stack B -> room 2 + room 3
Is it possible to have three Nexus 7000s ie one in each room (1,2 and 3) and have them setup like this:
Nexus 7000#1     vPC domain 1
Nexus 7000#2     vPC domain 1 + vPC domain 2
Nexus 7000#3     vPC domain 2
Thus gving all access switch stacks redundant links to the core withouit spanning tree.
I know its not ideal but its a campus site and thats how the existing fibre runs go.

From the following guide

http://www.cisco.com/en/US/partner/docs/switches/datacenter/sw/5_x/nx-os/interfaces/configuration/guide/if_vPC.html#wp1803465

vPC Peer Link Overview

You can have only two devices as vPC peers; each device can serve as a  vPC peer to only one other vPC peer. The vPC peer devices can also have  non-vPC links to other devices.

So no, you can't. Each Nexus can only establish a peer-link with one other chassis.

As a matter of fact, directly below that quote is a picture of exactly what you're asking under the heading "

Figure 7-4     vPC Peer Configurations That Are Not Allowed"

Cheers.

[Patrick Colbeck]

Its still ambiguos. I am not sure if the diagrams etc are referrng to a single vPC domain. I know you cant have >2 devices as vPC peers but whay happens if you create two vPC domains. The middle device is in both domains. Within each domain it only has a single peer.i

[nkarpysh · Accepted solution]

Hi

As I said it is just not possible to create two peer-links. You will not be able even to apply the second peer-link command. Does not matter how many domains you have. That limitation.

Nik

[Patrick Colbeck]

Thats a shame. It means they will have to use two contexts on the middle switch to get uplink resliance from the access layer stacks.

I dont like the three switch model but unfortunatley its dictated by the existing fibre runs on the campus.