Wireless Access

I had bought two Aruba 135 APs the CLI shows that it is missing the OS that usually comes pre loaded. Is there a way load OS onto the APs.

I have two more APs connected on LAN, will it download the OS via them?

It needs to get from the controller.

I do not have a controller at my location, I have just connected the New AP to the same network as the other two. Hope it does the job. Do let me know if anything else needs to be done.

Are they Instant APs?

If they are standard controller based ones, they need to get the image from the controller.  I have only done this when connected to the same subnet as the controller.

There may be a way to do it across a different network, but I can't say what that is off the top of my head.

If all of the APs are IAP-135 devices then pluggin them into the same subnet will work as they'll find the Virtual Controller and join the cluster. If these are AP-135 devices you'll need a mobility controller for them to work (http://www.arubanetworks.com/products/mobility-controllers/). AP-135 and IAP-135 are not interchangable and the AP-135 will never work with Instant devices (even though an IAP-135 can be converted to work with a controller). 

Controller based APs can get their image from across subnets as long as you use DHCP Option 43 or DNS for discovery of the controller. ADP is a L2 protocol so it only works in the same subnet as the controller.

That's true, but I was thinking that it was in a similar state as having had a "clearos" done to it.