802.11a versus 802.11b

[mondoughboy]

What are your opinions on 802.11a -vs- 802.11b? Basically, if you had to choose one or the other, not both, and you were to invest on only one architecture, which would you choose?

What are your pros and cons of either of the two.

I have been stumbling on this qestion for days, now it looks like i need to look for other people's insight.

:confused:


Thanks so much in advance for any input.

[MoleStrangler]

802.11b is more widley used and if you have a laptop (like my PowerBook) you are more likley to come across other 802.11b networks, 802.11a is still very new and more expensive than 802.11b, so you are going to find more 802.11b networks out there.

802.11a = 5.2GHz
802.11b = 2.4GHz

802.11b is still very slow when compared with 10baseT.

802.11a is a lot faster and it maybe possible to do backups in a reasonable time (have yet to test this).

If you are in Europe then you have no choice but to go for 802.11b. 802.11a will not be available for another 8-10 months, maybe.

802.11b may have a larger area of coverage than 802.11a when comparing similar speeds speeds.

802.11b = 1,2,5.5 & 11mbps
802.11a = 6,9,12,18,24,36,48 & 54mbps

Remember the high the data rate the closer you have to be to the Access Point. And as the 802.11a standard is 5.2GHz then you are going to have less range than the 802.11b 2.4GHz radio anyway.

Remember that each Access Point is like a single port. Everyone shares the same medium. So a switched 10mbps network will always outperform 802.11b. A wirelessLAN is not always the way to go, it all depends on your users.

So 802.11a maybe able to take most desktop traffic, but plan on more than 1 Access Point, always. But still plan on backups being a bit slow.

802.11b is more suited to adhoc users like sales people hot-desking, meeting rooms etc. Its not for all desktop users.

[rvandling]

If you can wait a bit, companies like SMC are developing access points that will handle both 802.11a and 802.11b. These points are ideal for companies who want to push the envelop but still be backward compatable.

However, I do have a questions about them... Let's say you are using your PDA or Laptop and it has a 802.11a/b NIC and you are currently connected on the 802.11a side... if you travel a bit with the device and move out of range for the 802.11a, will it automatically switch to 802.11b and maintian your connection??? If not, then I assume that when you are placing access points in a building, you need to set the distance between them to be optimal for 802.11a, right?

All in all though, these type of access points sound like the right answer. Also, I did read about the 802.11g standard. According to what I read, 802.11g works at 2.4Ghz, can transmit up to 54Mbs AND is backward compatible to 802.11b, is this correct?

Thanks for any input.

Rob

[MoleStrangler]

I cannot comment on companies developing new hardware. But it seems that they would have to write the software to handle the hand-over between the two standards. Note: This is not a part of the standard (I think) so there could be some initial compatibility problems.

@ the moment we have an Access Point that handles both 802.11a and 802.11b, there is no roaming between the two radios, its just allows customers to use clients with the two different technologies, easy for upgrades etc... There are also some other reasons for doing it this way.

You are correct about the location of the Access Point will differ when comparing 802.11a & 802.11b.

I have not seen the 802.11g draft yet but I would think they would have backward compatibility from 802.11g to 802.11b. I suspect that purchasing an 802.11g NIC would allow the client to talk to both 802.11g and 802.11b Access Points.