Cisco Nexus Fabric Extender Static Pinning Overview

The Nexus 2000 does not perform any local switching functions, and all traffic is switched in a centralized fashion by the parent switch. The front panel ports on a Nexus 2000 do not operate the same way that a normal switch port would and should be used only for host connectivity. One of the most apparent differences in operations between the Nexus 2000 and other switches is the implementation of BPDUGuard on all front-panel ports.

The initial configuration of the Nexus 2000 is simple and when configured can then be treated as additional ports configurable on the Nexus 5000 or 7000. The Nexus 2000 can be connected to the 5000 or 7000 in one of two distinct modes:

Static Pinning: This configuration creates a direct relationship between front-panel ports and their uplinks. The pinning is based on the number of uplinks available. For example, if one uplink is active, all front-panel ports are mapped. Static pinning is a good option in which tight control over the bandwidth and oversubscription is preferable. The drawback of static pinning is that if uplinks are added or removed, the host ports are bounced to repin the hosts across the uplinks. One to four uplinks are supported in this configuration.

Etherchannel: This configuration aggregates the uplink ports into a single logical interface that all front-panel ports are mapped to. As discussed later in the chapter, in an Etherchannel configuration only one, two, or four uplinks should be used. In this configuration hosts’ ports remain up if uplinks are added or removed. The uplink portchannel can also be a vPC to two different Nexus 5000s.

Shown in the diagram below is a basic example of Static Pinning –

cisco nexus fabric extender static pinning

Configuration below shows static pinning configuration between Nexus 5000 & Nexus 2000 –

NX5000(config)# fex 100

NX5000(config-fex)# pinning max-links 2

Change in Max-links will cause traffic disruption

NX5000(config-fex)# description FEX100

NX5000(config-fex)# exit

NX5000(config)#

NX5000# conf t

NX5000(config)# interface ethernet 1/17

NX5000(config-if)# switchport mode fex-fabric

NX5000(config-if)# fex associate 100

NX5000(config-if)# no shutdown

NX5000(config-if)# exit

NX5000(config)# interface ethernet 1/29

NX5000(config-if)# switchport mode fex-fabric

NX5000(config-if)# fex associate 100

NX5000(config-if)# no shutdown

NX5000(config-if)# exit

NX5000(config)# exit

 You can monitor the Nexus 2000 using the following commands:

  • show fex: Displays a list of fabric extension (FEX) units, their description, state, model, and serial number.
  • show fex fex-id detail: Provides verbose status information about a particular Nexus 2000. The output of this command provides details as to the software versions, operational configuration, uplink status, and much more.
  • show interface status fex fex-id: Displays the status of front-panel host ports on a particular FEX.
  • show interface ethernet mod/slot fex-intf: Displays front-panel hosts’ ports pinned to a particular Nexus 5000 interface.

Recommended Reading –

Also don’t forget to use and rate our DNS Troubleshooting tools