[c-nsp] Nexus FEXs and pinning max-links

[-Hammer-]

Someone showed me a document offline. I like your approach. Thanks for 
the hint.

Data Center Access Design with Cisco Nexus 5000 Series Switches and 2000 Series Fabric Extenders and Virtual PortChannels

http://www.cisco.com/en/US/prod/collateral/switches/ps9441/ps9670/C07-572829-01_Design_N5K_N2K_vPC_DG.pdf


-Hammer-

"I was a normal American nerd"
-Jack Herer



On 2/15/2012 9:16 AM, Bielawa, Daniel Walter wrote:
> For our N5k/N2k implementation, we choose to have our servers use port channels (via vPC) to connect to the N2k, and to then have an outbound vPC from our N5k's, instead of a vPC connecting the N2k's.
>
> Thank You
>
> Daniel Bielawa
> Network Engineer
> Liberty University Network Services
>
> (434)592-7987
>
> LIBERTY UNIVERSITY
> 40 Years of Training Champions for Christ: 1971-2011
>
> -----Original Message-----
> From: cisco-nsp-bounces at puck.nether.net [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of -Hammer-
> Sent: Wednesday, February 15, 2012 9:53 AM
> To: cisco-nsp at puck.nether.net
> Subject: [c-nsp] Nexus FEXs and pinning max-links
>
> All,
>       I've been playing with some Nexus gear in our lab and I'm confused on a physical layer issue. When defining the FEX, you define the max-links. Originally I set it to four and then built my port channel.
> Of course, it gave me an error
>
> ERROR: FEX max-links not configured to be one
>
> Which after googling and thinking thru makes sense. I'm defining the ports as a port channel so I need a max-links of "one". Not "four" (as in four wires between the N5K and N2K). That makes sense. What I'm struggling with is in what scenario I would NOT create a port channel.
> When would I just assign the physical links to the FEX and not build an etherchannel for them? Anyone?
>
>
> !!!get your FEX on
>
> !!!! define a FEX
>
> fex 101
>       desc FEX101
>       !!! define maximum links!
>       !!! trick question! If the link is a PO then your max links is 1.
>       pinning max-links 1
>
> !!!! define the port channel
> interf po101
>       !!! MODE!
>       switch mod fex-fabric
>       !!! associate it with the logical FEX
>       fex asso 101
>
> !!!! Bring the physicals (with the FETs connected) into the PO101 interf ra e2/1 - 4
>       !!! MODE!
>       switch mode fex-fabric
>       !!! call the fex!
>       fex ass 101
>       !!! call the PO
>       channel-group 101
>       no shut
>
>