Posts Tagged ‘fabric extender’

FEX configs are retained

Monday, February 15th, 2010

The N5k maintains the config of the FEXs, even when they’re removed (and even though it’s not visible to us). In this article, we’re going to look into this a little further… We’ll start with a working FEX, using Po100 (with Eth1/19-20 being the physical bundle members). (more…)

The FEX information is cached until it’s re-assigned to a different FEX

Tuesday, February 2nd, 2010

Continuing our journey into the world of FEXs on the Nexus 5000 and 2000, today we’re going to look at the behavior of the FEX configs themselves on the Nexus 5000.

All of the configuration and software information (firmware/images) for the FEX (Nexus 2148T) are kept on the parent switch (a Nexus 5000-series switch). Going on this, what happens when the FEX goes offline? Do I lose my config?

A stack of 3750 switches can be provisioned ahead of time, so that as stack members are added (assuming that they’re the correct type/model), no changes must be made – just move on. What kind of behavior is available on the Nexus 5000/2000?

I haven’t found provisioning available yet for FEXs on the N5k, however I did notice that the configurations for the FEX are retained when the FEX goes offline and online. This is great — if the 2148T fails or the fabric interface links are disconnected, the config will still be there (although not visible until the FEX comes back online). This article is looking at it from an association perspective (N2148T association with the N5k, not a configuration (actual port configs on the FEX). With that said, let’s explore this further… (more…)

What happens when the wrong serial number is entered for the FEX?

Sunday, January 31st, 2010

Continuing on the journey of FEXs on the Nexus platform, we’re exploring about serial numbers being statically bound to an FEX instance. It’s possible to allow any N2148T to connect to any FEX instance defined on a N5k. Simply plug in the N2k and off it goes.

This is a good low-maintenance approach, but what if I want to be more granular? What if I have several N2ks and I want to ensure that each N2k is plugged into the correct interfaces on the N5k? The only way to verify this is to tie a serial number to the FEX ID on the N5k, which will only allow that single N2k to come up on that FEX ID… or will it? What happens if the wrong serial number is entered?
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Introducing the Nexus 2148T (Fabric Extenders)

Friday, January 29th, 2010

The Nexus 5000-series (5010 and 5020) support the Nexus 2000-series of switches.  The Nexus 2000-series are fabric extenders (FEXs) – which is essentially a way to stretch out the N5k switch fabric.  Currently there’s only the Nexus 2148T switch, which we’ll cover (at least the basics) in this article.

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