Nexus 5548 interface hardware configuration

[stevecollz1]

We have a pair of Nexus 5548's.  My questions is regarding the hardware configuration of the interfaces.  The 5548 has 32 x 1/10Gb interfaces, are these interfaces hardware or ASIC independent, or are they grouped / oversubscribed in any way?

What I am trying to work out is if I was to connect a FEX or peer 5548 using 2 interfaces, am I OK to use interfaces E1/1 & 1/2 for example or would I be better off using a different combination of ports to give greater availability in certain hardware failure scenarios.

It looks like port 1-16 are on a separate daughter board to ports 17 - 32, but I may be wrong.

Any info that anyone could provide regarding this would be greatly appreciated.

[Lucien Avramov]

There is no oversubscription, the 5548 can do full 10 GB on all the ports. Feel free to connect the FEXs where it's most convenient for you.

[stevecollz1]

Ok, so no over-subscription.  When you say connect the FEX's where ever, does that mean that each port is completely independant of each other in terms of internal wiring etc.

[Lucien Avramov]

Take a look at the architecture white paper:

http://www.cisco.com/en/US/prod/collateral/switches/ps9441/ps9670/ps11215/white_paper_c11-622479.html

[Anahita Abdollahifar]

I found this article in Network computing

http://www.networkcomputing.com/data-networking-management/how-to-set-up-cisco-nexus-fabric-extende/240147148

which is written in 2013.

it mentiones:

"In the Nexus 5500s, ASICs are mapped to groups of 8 consecutive Ethernet ports on the front to the switch, 1-8, 9-16, etc. Therefore, spreading FEX uplinks over ports 1 and 9 is smarter than 1 and 2. If the ASIC servicing ports 1-8 fails, you won't lose both FEX uplinks."

Is this correct or not?

I have 2 Nexus 5548up, and want to know about different group between 32 fixed ports!

[Steve Fuller]

Hi Anahita,

It is correct that eight consecutive ports of the Nexus 5500 series use the same ASIC. If you take a look at the attached screen scrape from the Cisco Live session BRKARC-3452 - Cisco Nexus 5000/5500 and 2000 Switch Architecture you can see that the switch consists of a number of UPC (Unified Port Controller), each providing connectivity for a group of eight ports.

If you want to connect to a Nexus 5500 series switch in the most resilient way possible then connecting to ports 1, 9, 17 etc., would remove the UPC as a single point of failure. Note though that there are other SPOFs in the Nexus 5500 series switch e.g., the crossbar fabric ASIC, so you should design end system resilience accordingly.

Regards