N2k 2248PQ Can active/active be achieved to multiple N7K switches with one QSFP–4SFP10G?

[jheck@woodforest.com]

Can I uplink one N2k 2248PQ to two upstream N7K using one QSFP–4SFP10G cable, or does the upstream switch have to be one N7K?

Nexus 7K's are running 7.2(2)D1(2)

[Reza Sharifi]

If the 7ks have 40gig ports and are not far from the 2k, you can connect them directly using 40gig interfaces using this type of cable.

Cisco QSFP-H40G-CU5M

HTH 

[jheck@woodforest.com]

Thank you for the reply. I have 10Gig ports in my 7K's. Do you know if I can do what I am asking with the one QSFP–4SFP10G copper cable to two 7K's upstream? I know It will work to one upstream 7K

[Reza Sharifi]

I am not sure if that is going to work. In your case, the 2k is 40gig and the parent switch (7ks) is 10Gig.

In order for the breakout cable to work you would need to use the breakout command on the parent switch, but in this case, the parent switch is 10 and not 40.

HTH 

[clsulliv]

The 2248PQ does not have true 40gig uplinks. The uplink is structured in 4x10g lanes so the cable or connecting it to 10 gig ports will not be a problem. As for whether or not you can dual home the fex using a single uplink, I am not sure. I know that if you use any number of the links, you should be able to bring up the FEX to the parent switch.

I can see if I can find some information about dual homing in this fashion.

[Reza Sharifi · Accepted solution]

So, even if the FEX uplink ports are structured as 4x10 gig, the same restriction of not being able to use the breakout command should apply.

HTH

[jheck@woodforest.com]

Thank you very much. I figured as much. I will probably try it just for kicks to see but I think you have confirmed what I thought. 

[clsulliv · Accepted solution]

There is no need to use the breakout command here. The breakout command would only be necessary if we are trying to connect the 2248PQ to a 40gig port. Since the 2248PQ is 4x10g in a QSFP form factor, it will not link up and would require that port to be broken out. When using a break out cable, the QSFP end will be used on the FEX and will connect to the 10 gig ports on the N7K if it does not have 40 gig ports.

This is discussed here for n5k/n6k but will apply to n7k as well

https://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus5000/sw/operations/interfaces/602_n1_1/N5K_Interfaces_Ops_Guide/n5k_qsfp-_portsoperations.html

[jheck@woodforest.com]

Thank you very much.