Showing results for 
Search instead for 
Did you mean: 

UCS uplink to Nexus 2K


Hi to All,

We are on the process of deploying 2 Nexus 7k, 2 nexus 5K and a bunch of nexus 2k in our data center, we use vPC inside our data center, we do have UCS is our DC which is currently connected to our 6509E core switch via port channel with 1GB link speed each physical link having a bundle of 4GB aggregated bandwidth. Since we will replace the 6509E with the Nexus platform, our 5K will be the aggregation and is having vPC to the 7K, while the 2k is also having vPC to 5K. My plan is to connect the the fabric of my UCS (total of 4 links in each fabric) via layer 2 port-channel via trunk mode on my nexus 2k, allowing specific VLAN on the trunk ports, this is the same set uo with my 6509E switch. My concern is does the N2K support this type of deployment? I am aware that I can connect the UCS either on my 5K's or 7K's I just want to know if there are any caveats if I use the 2K and atthe same time I don't have to procure addition SPF's if I connect it to my 2K. Please advise...


Best Regards,


20 Replies 20

Walter Dey

Best practise for UCS connectivity is 10G wire rate vPC to Nexus 5k or Nexus 7k ! Therefore N2k is not recommended. Btw. if you need native FC, it means FCoE, and not all N2k models support FCoE!

Hi Walter,

I don't need native FC as of this moment as we do have our own SAN infrastructure, can you tell me the issues that I may face if I use my 2K?



Oversubscription and Hop Count.

Don't forget, that in any UCS domain, you might have East - West L2 traffic, that has to leave and reenter the UCS domain (has been discussed in this forum many times), in addition to East - West traffic which is L2 switched inside UCS domain on the fabric interconnect.

I remember the early days of UCS, when customers did 1G North bound connections, and ended up in a bottleneck.

I know a hundreds of UCS implementations, and not a single one has connected UCS to a N2k (FEX).

Anyway, it's a commercial argument, saving port licenses, I know;

Again: best practise is vPC from UCS FI to a N5k or N7k.

Good luck