Solved: Nexus 5010 uplink to VSS-1440

First Team Netops · ‎03-10-2009

We are deploying a new set of VMware server farms and would like to use the Nexus line for these 40 servers. Does is make sense to connect these via layer 2 to our VSS on a WS-X6708-10G-3C? Or should we wait a few years until we have a budget for a pair of Nexus 7k's and run everything to the VSS? thanks

ltd · ‎03-11-2009

hi Jim,

Nexus 5000 is a L2 switch, so pretty much whatever you do, its going to be a L2 Portchannel 'northbound' from N5K up to the C6K VSS pair.

Your VSS pair would be the L2/L3 boundary, so you'd have a SVI configured on it that is the L3 default gateway (from your servers).

Best practice would be that you distribute the portchannel members across the pair of physical switches in the VSS pair.

I'm involved in the development of the Nexus range within Cisco, so I'd be all for recommending you deploy Nexus 7000 too. :) But the reality is that you can probably achieve what you want today with C6K VSS, and in future if you did deploy Nexus 7000 too, you could make use of virtual Port Channel (vPC) to allow for full bisectional bandwidth from 'access' to 'agg/core' without any blocked links in STP.

vPC is available today on N7K and provides roughly similar L2 multichassis etherchannel as what VSS enables today in C6K VSS.

hope that helps.

cheers,

lincoln.

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colin.mcnamara · ‎03-11-2009

Nexus 5k's uplinked to a VSS cluster is a perfectly fine solution (and the most economical for smaller setups). I personally have a couple of customers that have that setup, and it works fine.

One thing to keep an eye on with the WS-X6708-10G-3C is that it is oversubscribed (4 ports straight to the back plane, and 4 ports that hit MUX chips). If you are using all of these ports coming out of your 5k's (8 to each 5k) then it may make sense to just use a 4 port card and not be oversubscribed.

First Team Netops · ‎03-11-2009

Can you tell me if in your experience with this topology do you setup the connection to the VSS on layer 2 or 3 or does it just depend on the farms connected to each switch domain?

Thanks,

Jim

colin.mcnamara · ‎03-11-2009

Well, the 5k is layer 2 only. So it is layer 2 port channels up into the VSS cluster. I normally recommend putting the l3 boundary in the VSS cluster, and then routing out into your core.

ltd · ‎03-11-2009