Impact of 802.11b legacy devices on higher spec 802.11x wireless LANS

[shane_king]

I have a healthcare client that is a high care facility surrently running AP121's soon to be replaced with AP122's

They are about to retire their existing cable based Nursecall System with a 3rd party product that only operates on 802.11b. At present all devices (Laptops, Tablets, Vocera Badges) connected to the AP's are 802.11n capable so transaition to the AP122's wasnt going to be an issue.

What is the impact of having legacy devices running 802.11b when all others run at higher rates? The WIreless LAN has run flawlessly for 5 years since installed, and my concern comes from my limited understanding of what I saw with a Ruckus deployment at an equivalent site where the Ruckus units would ramp down to accomodate the 802.11b devices then after a period ramp back up to 802.11n. This lag time affected other services on the site such as Telehealth Video Conferencing (*where a patient was engaged in a consult with a GP or specialist Dr via viedo link attached to the Wifi)

Is there a deadline for 802.11b to eb EOL by the IEEE or Wifi Alliance? SHould I be concerned?

[shane_king]

Thanks Brian, we are on the same page with my suspicisions and ensured I am on the right track with the AH sites I support.

The product is a Nursecall System called Alexys here in Australia and they are still producing a product that runs in the 802.11b. It also seems dfue to the lack of responses that they dont intend to change. I've been suspicious of vendors who have a "reluctance" to move with the times seeing it as an indicator that the product development has stalled or the vendor simply cant keep up with developments in new tech.

Sadly the Board of Dir's for the client made the call on the vendor without much consultation, so were stuck with it. Perhaps its a little paranoia on my side too given the Wireless environment has been issue free for 5 years with every piece working nicely and logs being a very very boring read 🙂

Wish me luck

[bpowers]

Any time there are legacy devices on a WLAN, there will be some degradation of service. The 802.11 protocol allows for backwards compatibility, but it comes at a cost. Determining said cost however can be difficult. If your new system is the only thing operating on the 2.4 GHz network and everything else lived on the 5 GHz network, you could minimize it's impact. That would be my approach I believe if I wasn't able to convince the proper party that this new 802.11b system was simply not a good idea.

The 802.11b devices would not support any of the enhancements that led to the increased speeds w/802.11n/ac. No channel bonding. No Block ACKs, no short GI. RTS/CTS would almost have to happen all the time to lock access to the medium for the newer devices since they'd be talking basically gibberish that could not even be decoded by the legacy devices since they'd be using data rates that an 802.11b devices simply would not understand.