Cisco Switzerland Technology Blog

Release Recommendations for WLAN-Controllers

Wednesday, 21 December 2016

My last post about the Release-Numbering of WLAN-Controllers raised a couple of more questions – actually already while writing and discussing it with Cisco-Peers.
And the questions were all somehow similar.

When I go to and look for SW-Images of my WLAN-Controller, I do find about 10, 15 or more different releases to download.
Based on your post I can understand how the release-number is being defined … but which release should I really use now?”

I therefore decided that this blog-post should be about the question “What AireOS-Release to use?”

To say it upfront – if you want a very concrete recommendation from Cisco on this topic, there is a service you can buy!
My colleagues of Cisco Services will analyze, which SW-Release is going to match best your requirements and fit into your network infrastructure. Based on that analyzes they will recommend a specific release to you.

To be really honest:
We as Sales SEs cannot do that; we’re actually not even allowed to do that!
However, in this blog I want to give you some guidance, so you can do at least some of the steps yourself.


Before we can dig into selecting an AireOS-Release for your productive network, we need to discuss and understand a few terms.



I already described in my previous post, how you can identify MR-Releases based on the AireOS-Release-Numbering.
Now, later MR-Releases usually indicate more stable releases than earlier images – simply because they contain more bugfixes.

Now, under special circumstances it happened in the past, that MR releases also contain support for new features or Hardware.
That usually means completely new code … and with any new code, there is the potential for new bugs.

And as in the last post I can make the same suggestion how to tackle that:
Read the release-notes carefully – there you will be see what (if at all) new features have been included.


“ED” and “MD”

When you are on the Software-Download-Pages for AireOS-Releases you will quickly recognize, that there are mostly SW-Images marked with “ED” and just a few marked with “MD”.
What does that mean?

ED = Early Deployment (ED) releases
ED-Releases provide new features and new hardware platform support in addition to bug fixes.
These releases are categorized as Early Deployment (ED). These are short-lived releases.

MD = Maintenance Deployment (MD) releases
MD-Releases provide bug-fix support and ongoing software maintenance.
These releases are categorized as Maintenance Deployment (MD) and may be part of the AssureWave program.
These are long-lived releases with ongoing software maintenance.

I allowed myself to copy above definitions from the following Cisco.Com-Page:

This Cisco.Com-Page also lists the advantages of each:
ED-Releases allow customers to deploy the latest features and new hardware platforms or modules.
MD-Releases provide customers with a software release that offers stability and long support duration with periodic maintenance releases (MRs).

Beside these definitions the mentioned Cisco.Com-Page also reveals much more details about:
– the AssureWave program
– ED- and MD-Release recommendations for AireOS
– some more detailed release recommendations fro AireOS starting 7.0

I really recommend you have a look and might also bookmark this page, as it will be updated from time to time.

And how does this now help?
When choosing the next AireOS-Release you need to think, where you want to put your focus.
To you want the latest and greatest, then you probably end up with ED-Releases – if your focus is on stability, then you probably want to choose an MD-Release.

When would you probably end up with an ED-Release even you would like to put your focus on stability (aka a MD-Release)?

If you’re using new Hardware or mandatory need a specific new feature, you probably have to use a ED-Release.


Is there more information available that might help choosing the right AireOS-Release?
Yes, there are!

“Latest” vs “Suggested”

On the Software-Download-Pages there are several other terms listed.
Beside some obvious ones there are these two – but what do they mean?

This tab is easily explained, as it just lists the latest available release for each SW-Train.
There is really no other meaning to this than what the name says: This are the latest images available.

Yes, later images most likely have more bugfixes included.
But if the SW-Train-Number also increases, there are potentially new bugs introduced with new features.

This tab is much more interesting to discuss – so these are the suggested releases.
Does that mean we have found what we’re looking for? Do we as Cisco recommend everyone to use one of these releases?

Well, not entirely!

These suggestions are automatically generated based on some metrics and marked with a star on Cisco.Com.
And these metrics may or may not have any relation to your requirements and expectations for your productive network.

My personal advice therefore is:
The star on Cisco.Com is indeed an indication, but it’s only an indication.
These releases are probably worth of being evaluated more closely – but don’t choose it just because of this “star”.

Again, dig into the release-notes and see, what features and hardware it supports; what open and closed caveats are listed, etc.


Before concluding this post, there is one more important source of information:


Our friends at our Technical Assistance Center (TAC) also publish their suggestions.
TAC-People are support people, they do not belong the Engineering, Product Marketing nor Sales.
Their recommendations therefore are only based on what they see in practice.

You can find their suggestions on the following Cisco.Com-Page:

For many customers this link is probably exactly what they are looking for.
But I have to repeat myself:
Also this you should use as an indication – probably one with a quite preferable weighting.

In any case you should have look into the release-notes and verify, if that release probably would suit your network.



If you as a customer want a recommendation for specific release, you can buy this as a service from Cisco Services.
Other than that, you need to weight the different arguments, release-notes, etc. and decide yourself.

To conclude this post I want to add following table (by my Austrian colleague Stefan Honeder), which summarizes pretty well


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