Connecting a Nexus 2148 to a Nexus 501030 November 2010 · Filed in Tutorial
The Cisco Nexus 2000 series fabric extender (or “fex”) is an implementation of network interface virtualization. Because the Nexus 2000 fabric extender acts as a remote line card to the upstream IV-capable bridge (a Nexus 5000 series switch, typically), all the configuration takes place on the upstream bridge. In this post, I’ll describe how to connect a Nexus 2148T to a Nexus 5010. In reality, the process is incredibly simple and not really worthy of a blog post, but in the interest of completeness I’ll document it here.
The key to making the fabric extender work is the
switchport mode fex-fabric command, used on a specific interface to let the Nexus 5000 know that a fabric extender is connected to that port:
nexus(config)# interface eth2/1 nexus(config-if)# switchport mode fex-fabric
You can use the
switchport mode fex-fabric command on a specific interface, as shown above, or on a port-channel:
nexus(config)# interface port-channel 2 nexus(config-if)# switchport mode fex-fabric nexus(config-if)# interface eth2/1 nexus(config-if)# switchport mode fex-fabric nexus(config-if)# channel-group 2 mode on nexus(config-if)# interface eth2/2 nexus(config-if)# switchport mode fex-fabric nexus(config-if)# channel-group 2 mode on nexus(config-if)# interface port-channel 2 nexus(config-if)# fex associate 100
In this example, I created a port-channel with two interfaces and associated the fabric extender to the port-channel, providing link-level redundancy for the connection between the Nexus 2148 and the upstream Nexus 5010.
To verify that the fabric extender is coming online properly, you can use a few different commands. The
show fex detail command produces some useful output (only the first several lines are included here):
FEX: 100 Description: FEX0100 state: Online FEX version: 4.2(1)N1(1) [Switch version: 4.2(1)N1(1)] FEX Interim version: 4.2(1)N1(1) Switch Interim version: 4.2(1)N1(1) Extender Model: N2K-C2148T-1GE, Extender Serial: JAF1321ANJN Part No: 73-12009-05 Card Id: 70, Mac Addr: 00:0d:ec:cf:03:42, Num Macs: 64 Module Sw Gen: 12594 [Switch Sw Gen: 21] post level: complete pinning-mode: static Max-links: 1 Fabric port for control traffic: Eth2/1 Fabric interface state: Po2 - Interface Up. State: Active Eth2/1 - Interface Up. State: Active
And that’s really about it. Yes, there are more advanced configurations—I’m interested in exploring the use of virtual port-channels upstream of a Nexus 2000 series fabric extender to multiple Nexus 5000 switches—but this will get you started.
Feel free to post corrections, suggestions, or any other feedback in the comments!Tags: CLI · Cisco · Networking · Nexus Previous Post: SAN Port Channels from Nexus 5010 to MDS 9134 Next Post: VLAN Trunking Between Nexus 5010 and Dell PowerConnect Switches