[NTLUG:Discuss] Wireless Home Network -- 802.11 v. 11a v. 11b v. 11g v. "54g"

[Bryan J. Smith]

Jack Snodgrass wrote:  
> the wireless part is easy... it's the brand/type that's hard...

Everyone seems to like the Linksys WRT54G which is a MIPS (probably a,
64-bit R4000 variant, like the original PSOne and N64, varies between
125-200MHz)  Linux box with a good amount of EEPROM and SDRAM (varies
between 4-8MB and 8-32MB, respectively).

There are now Linux kits that let you build your own firmware, being
that Linksys' solutions have been Linux-based for some time.  Many other
vendors are as well -- even if they use an ARM and uCLinux (ARM8/9 does
not have a MMU, but some higher-end ARM variants, like StrongARM/XScale,
do).

About the only complaint I have about the Linksys solutions it that they
make is damn hard to switch away from the default channel of 6 in their
router and Windows drivers (just set my father up the weekend for Day's
day).  I like running on channel 9 for various reasons -- including
trying avoid issues with 2.4GHz cordless phones (WLAN typically wins).

> wireless-b 11Mbit - cheap ( becuase of all of the G stuff ) 
> wireless-g 54Mbit 
> wireless-g Plus - 108mbit ( uses two channels at once... may 
> 				cause more interference ) 
> wireless-g w/ speed boost ( uses one channel, but timed to go faster )
> All of the G stuff should work at the 54Mbit G speed. 
> The 'faster' stuff only works with like equipment. 
> A 'b' thing will probably slow down the network to b ( 11mbit ) 
> speed. 

There IEEE802 standards are as follows:  

 802.11   2.4GHz   2Mbps
 802.11a 5.0GHz 54Mbps
 802.11b 2.4GHz 11Mbps
 802.11g 2.4GHz 22Mbps (yes _22_Mbps)

2.4GHz is world-wide.  The original .11 was 2Mbps, .11b was 11Mbps and
the .11g has _always_been_ 22Mbps!  The 54Mbps speed is a stretch of the
spec that the IEEE could never get stable enough to standardize, but
that hasn't stopped people.  Only 22Mbps is guaranteed on .11g, although
most vendors have been able to "scale" the speed higher based on the
signal quality.  That's why they are labelled "54G" and if you read the
specs, 802.11g is only 22Mbps.

802.11g was designed to be backward compatible with 802.11b and 802.11.

5.0GHz is a bandwidth not available world-wide, but 802.11a  typically
does give you a far more reliable 54Mbps connection.  The range is
shorter, but I was messing with it back in 2001 (along with 802.11g)
and we always found it perferrable to 802.11g.  That might have changed
now, but the IEEE kept 802.11g at 22Mbps for a reason.

You need a dual-band (i.e. far more costly) access point to do both
802.11a and all the other 802.11/b/g speeds.

> lots of choices / decisions. Once you pick one, it should work fairly
> easily.... the distance / speed usually isn't as fast / far as 
> advertised. 

Exactomundo.  The IEEE 802.11 specification is always your key.
Vendors continue to overstate the capabilities.

But I was able to get 22Mbps from one side of my father's house to the
other with the WRT54G Linksys plus a Linksys PCCard.  Using my 4 year old
Intersil Prism 2 MAC at 802.11b, I was able to go outside.


-- 
Bryan J. Smith, E.I. -- b.j.smith at ieee.org