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Choosing products for racks and aggregation layers


I am practicing designing a data center and have a question regarding the best choice of products.

I have 30 racks. In each rack I have 2 switches (NIC Teaming) and 20 servers which each have 2 x 1G NICS and 1 mgt NIC.

What sort of rack model and switches would I choose? I think I would use for the rack and find line cards with at least 30 ports correct? What switches?

I also have 2 aggregation switches that connects to all the racks. What product would I choose for this? Would that just be this:

Anythign else I need to consider?

7 Replies 7

Andras Dosztal

What about a collapsed aggregation/access design? You can use Nexus 2K (N2K-C2248TF-E) for ToR switches and N7K for the fabric of the 2Ks and for aggregation.

Most of the time I recommend to use the racks of your servers' vendor.

I get a little confused with the terminology, so let me see if I get you.

For each rack I would add 2 switches (

N2K-C2248TF-E) and for my aggregation switches I would use the n7k?

For example:
C1 and C2 are my n7ks and a-h would be my racks?


Yes. The N2K acts as a remote linecard so you don't have to manage them separately, but the 7Ks only. There's one drawback tho: the N2K doesn't have a backplane, so it can't switch locally; everything goes up to the parent switch. It can be a problem when your servers communicate with each other a lot.

Interesting solution. But that would mean I cant use vMotion if I were to? as the servers cant talk to each other? Or would it be possible still?

They can talk to each other, but all traffic goes up to the parent N7K first, which leads to a 1.2:1 oversubscribe ratio (48x 1G access vs 4x 10G fabric); though it's not a high rate, could be worse if the FEX had 10G access ports.

I have a few other questions not entirely related that I would love some advice on:

1) If my rack servers have an HBA for SAN, should I connect these to my aggregation switchs (n7k)? or should  I have another dedicated witch for this SAN?

2) Also in the future if I upgrade a few servers to have 2x10G ethernet ports, could the current n2k and n7k support these new speeds or would I have to upgrade anything?

3) The n2k will initially connect to the n7k using 10G but in the future i may upgrade this to 40G. Would I encounter any problems?

4) for the n7k, would this model switch be fine:

5) Can you recommend a console port terminal server? I think id use this for accessing the switches.


Mate There is a lot of questions we can ask as to why you chose this design. But honestly Slipping in a Pair of Nexus 5596UP at the agg with the N7K in the core would be good. But again the constraint of budget is there. Also What is the core made of is a question.

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