Autonomous Management

‘Downgrading’ a Cisco Lightweight AP to Autonomous mode

 

Key notes

Not all Cisco models can function as either Lightweight or Autonomous APs. Check out the Cisco Compatibility Matrix to see if your model is listed as Controller capable and if it doesn’t appear within those tables then it probably isn’t! If you have a closer look at the tables you will also see either ‘LAP’ or ‘CAP’ preceding the model number of the AP with LAP indicating the model is available in both formats and CAP indicating that the AP is only available in the Lightweight format. If you have a look on the back of an 1142 AP for example, you may see either AP1142 indicating autonomous by default or LAP1142 indicating Lightweight by default but both are capable of performing as either! However on the back of 3500 AP you will see CAP35xx as it is Lightweight capable only… mostly. You can technically use the 1260 autonomous image on them but it is definitely unsupported by Cisco TAC. Just to make sure you’re not napping the newest shiny range from Cisco – the 3600 series – comes as CAP36xx only but there is an official Autonomous image available which I have played with and it works fine so perhaps Cisco will continue to make future APs either/or… very confusing.

*Update 20th August 2013*

Cisco have announced the End of Sale (EoS) of 1142 APs and have also made the Autonomous image for both 3500 and 3600 APs available. This method of downgrading still works for either AP however you may need to change the name of your default-tar image to match whichever model you are configuring.

Before you start

You will need the following:

  1. An autonomous IOS for your Access Point from http://software.cisco.com/download. You’ll need to be logged in with a registered account linked to a Cisco support contract.
  2. Be connected to your AP via a console connection and Ethernet connection.
  3. Configure your local machine IP within the range 10.0.0.2 – 10.0.0.30.
  4. Be running a local TFTP server with the IOS image in the root directory. I use tftpd32 as it is nice and free and Solarwinds used to max out at a certain file size.
  5. Rename the IOS image to cXXXX-k9w7-tar.default with XXXX being the model number, e.g c1142-k8w7-tar.default in my example below.
  6. Turn off your local firewall (if you feel it is safe to do so).

If you are in the office it can be quite irritating to keep physically and virtually switching between your company network and the AP you are configuring. I bought a few cheap USB to Ethernet adapters off ebay that suit the job perfectly as I don’t need them to perform Gigabit uplinks but simply have enough clout to transfer some IOS images. So far my first one hasn’t died after six months use so that was $2 very well spent.

The Process

Turn off the power to your AP and then power it back on with your finger on the mode button at the back. After around 20 seconds the LED on the front should turn solid red and you can let go. If you are watching on the serial connection then you’ll see the AP report the mode button was pressed down and it will reset its IP to 10.0.0.1 and enter the image recovery process.

LW-Auto1
Figure A – Resetting the AP

Seeing as you setup everything perfectly the local tftp server will tell you it is sending a file over to the AP. A couple of common things that prevent this occurring are:

  1. Ensure your firewall is turned off (again)
  2. If you are using Solarwinds I recall the default option to send files upon request (or something along those lines) is turned off so just go into the properties and make sure that is turned on. My apologies for the vagueness of that suggestion. If in doubt you could turn everything on..not that I’m suggesting that.

Fig B shows the name of the file in my root tftp directory and figure C indicates what you should see when a file is being sent over.

LW-Auto2
Figure B – TFTP Root directory
LW-Auto3
Figure C – Flash transfer via TFTP

Upon completion of the transfer the AP will reboot itself et voila you can log in with the default credentials – Cisco / Cisco – and go autonomous configure crazy! To verify you can always do a show version to see what IOS the AP booted off. One other indication is you shouldn’t be able to enter the global conf t mode on an AP in Lightweight mode.

Lw-Auto4
Figure D – AP booted into Autonomous mode

Final thoughts

I’ve added any hints and tips that spring to mind along the way. If you are in doubt about what to do or get stuck then you can comment on here but may find you get a much quicker response on the Cisco forums. The professionals on there are extremely helpful and enviably knowledgeable!

I’ll do another post at some point detailing how to upgrade from Autonomous to Lightweight as there are several ways to do it and also on how to do these upgrades/downgrades remotely which can come in very handy and score you some client brownie points.

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2 thoughts on “‘Downgrading’ a Cisco Lightweight AP to Autonomous mode

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