What happens when more links are associated with an FEX than are permitted in the max-links parameter? Let’s find out…
Posts Tagged ‘max-links’
Experimenting with Static Pinning
Thursday, February 4th, 2010The FEX information is cached until it’s re-assigned to a different FEX
Tuesday, February 2nd, 2010Continuing 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…)
Methods for connecting FEXs
Friday, January 29th, 2010If you’re wondering what an FEX is, check out this article: http://www.cciezone.com/?p=231.
FEXs are connected to the parent switch(es) via fabric interfaces. These are 10Gbps interfaces which connect the two switches (think of a stacking cable on a 3750-series switch).
There are two methods of configuring fabric interfaces:
- Static pinning
- EtherChannels
Although these are somewhat differentiated in some of the documentation, the static pinning looks almost the same as that used for EtherChannels. The main difference is that static pinning uses physical interfaces, whereas EtherChannel uses a single Port-Channel interface for the fabric interface (there are some minor configuration differences and requirements as shown below).
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