802.11b to 802.11g upgrade gotchas

I've been using 802.11b in our house for a couple of years and
have been pretty happy with it except for a couple of issues. the
first is security. My ancient equipment only supports 64 bit
WEP. But I'm not hiding any state secrets and it seems unlikely
that any of my neighbors is sophisticated enough to implement a
brute force attack and gain access to my LAN. The other issue is
network bandwidth. 802.11b is fine for Internet surfing through a
cable modem, but I also have run X11 applications over the network
and some of them - particularly the graphical ones - would benefit
from more bandwidth. So I'm looking at 802.11g

Right now my wireless LAN consists of an AP (D-link 614+) Thinkpad T30
with a miniPCI adapter and another laptop with a PC card adapter. My
Thinkpad would benefit most from the bandwidth. The other laptop
is my music jukebox and 802.11b is adequate for that, though I
could benefit by replacing the PC card adapter with something that
uses Ethernet. It is a VAIO with one PC card slot and the Wifi card
prevents me from using the external CD-ROM. Occasionally my sons drop
by with their 802.11b equipped laptops and join the LAN. (Wireless
is way cool technology, but you already knew that.

Additionally the 614+ seems to be having issues. Occasionally I need
to power cycle it when my other devices lose connectivity. It may
be preparing to die.

My first thought was to replace the 614+ with an 802.11g
AP and upgrade the Thinkpad also. But I read that
mixing 'b' and 'g' on the same AP may the AP to drop
the speed to 'b' capabilities. I did see one review of the
D-link DI-624 that indicated that not all routers seem to suffer:
http://reviews.cnet.com/D_Link_DI_62...5.html?tag=top
(http://tinyurl.com/6twbo). Their comparison shows that the Dell
Wireless 2300 drops from 23.5 Mbps with only 'g' clients to 18.2
Mbps when 'b' clients are added. Too bad it can't match the WGT624
throughput of 47.1 Mbps (which drops to 12.1 when 'b' is added.) My
googling has not found any similar reviews so I am unable to find
out if other reviewers came up with the same results.

My first question is if there is an AP that supports high throughput
for 'g' devices while serving both 'g' and 'b' devices.

Barring that, is it possible to run my 'b' AP side by side with a
'g' AP and avoid mixing 'b' and 'g' on the same AP? Would the very
presence of a 'b' device cause the 'g' device to revert to slow
operation? For that matter, could a neighbor's 'b' LAN cause my 'g'
LAN to degrade even if we don't share IDs or WEP keys?

If I program my 'b' system to shut down wireless when not in use, will
the 'g' AP resume higher throughput operation, or will it remember
that "there is a 'b' out there somewhere" and remain downgraded
until the next power cycle or whatever.

Oh, yeah. The other wrinkle is that there seems to be no miniPCI
802.11g adapter for the Thinkpad T30. IBM does not list one for the
T30 and third party devices seem to warn that the T30 has firmware
that prevents usage of other than approved devices. So much for
miniPCI interoperability.

Thanks,
hank

You can run a b ap and a g ap on separate channels and on the G ap select
operate in G mode only instead of mixed mode. Make the ssids different.

By the way I just got a Thinkpad t42, its an awesome laptop and worth the
extra few bucks over the competition anyday.

"Hank Barta" <(E-Mail Removed)> wrote in message
news9Mnd.432327$D%.89866@attbi_s51...
> I've been using 802.11b in our house for a couple of years and
> have been pretty happy with it except for a couple of issues. the
> first is security. My ancient equipment only supports 64 bit
> WEP. But I'm not hiding any state secrets and it seems unlikely
> that any of my neighbors is sophisticated enough to implement a
> brute force attack and gain access to my LAN. The other issue is
> network bandwidth. 802.11b is fine for Internet surfing through a
> cable modem, but I also have run X11 applications over the network
> and some of them - particularly the graphical ones - would benefit
> from more bandwidth. So I'm looking at 802.11g
>
> Right now my wireless LAN consists of an AP (D-link 614+) Thinkpad T30
> with a miniPCI adapter and another laptop with a PC card adapter. My
> Thinkpad would benefit most from the bandwidth. The other laptop
> is my music jukebox and 802.11b is adequate for that, though I
> could benefit by replacing the PC card adapter with something that
> uses Ethernet. It is a VAIO with one PC card slot and the Wifi card
> prevents me from using the external CD-ROM. Occasionally my sons drop
> by with their 802.11b equipped laptops and join the LAN. (Wireless
> is way cool technology, but you already knew that.
>
> Additionally the 614+ seems to be having issues. Occasionally I need
> to power cycle it when my other devices lose connectivity. It may
> be preparing to die.
>
> My first thought was to replace the 614+ with an 802.11g
> AP and upgrade the Thinkpad also. But I read that
> mixing 'b' and 'g' on the same AP may the AP to drop
> the speed to 'b' capabilities. I did see one review of the
> D-link DI-624 that indicated that not all routers seem to suffer:
>
http://reviews.cnet.com/D_Link_DI_62...5.html?tag=top
> (http://tinyurl.com/6twbo). Their comparison shows that the Dell
> Wireless 2300 drops from 23.5 Mbps with only 'g' clients to 18.2
> Mbps when 'b' clients are added. Too bad it can't match the WGT624
> throughput of 47.1 Mbps (which drops to 12.1 when 'b' is added.) My
> googling has not found any similar reviews so I am unable to find
> out if other reviewers came up with the same results.
>
> My first question is if there is an AP that supports high throughput
> for 'g' devices while serving both 'g' and 'b' devices.
>
> Barring that, is it possible to run my 'b' AP side by side with a
> 'g' AP and avoid mixing 'b' and 'g' on the same AP? Would the very
> presence of a 'b' device cause the 'g' device to revert to slow
> operation? For that matter, could a neighbor's 'b' LAN cause my 'g'
> LAN to degrade even if we don't share IDs or WEP keys?
>
> If I program my 'b' system to shut down wireless when not in use, will
> the 'g' AP resume higher throughput operation, or will it remember
> that "there is a 'b' out there somewhere" and remain downgraded
> until the next power cycle or whatever.
>
> Oh, yeah. The other wrinkle is that there seems to be no miniPCI
> 802.11g adapter for the Thinkpad T30. IBM does not list one for the
> T30 and third party devices seem to warn that the T30 has firmware
> that prevents usage of other than approved devices. So much for
> miniPCI interoperability.
>

> Thanks,
> hank

On Sat, 20 Nov 2004 18:37:23 GMT, in alt.internet.wireless , Hank Barta
<(E-Mail Removed)> wrote:

> My first thought was to replace the 614+ with an 802.11g
> AP and upgrade the Thinkpad also. But I read that
> mixing 'b' and 'g' on the same AP may the AP to drop
> the speed to 'b' capabilities.

many (most?) newer routers don't have this problem as they can segregate
the B and G traffic to an extent. look for Mixed Mode or something like
that on the box.

> Barring that, is it possible to run my 'b' AP side by side with a
> 'g' AP and avoid mixing 'b' and 'g' on the same AP?

Yes, but tricky - you'd have to force the B devices to use a different
channel to the G devices, and they may wander off between APs unexpectedly

> If I program my 'b' system to shut down wireless when not in use, will
> the 'g' AP resume higher throughput operation, or will it remember
> that "there is a 'b' out there somewhere" and remain downgraded
> until the next power cycle or whatever.

No


--
Mark McIntyre
CLC FAQ <http://www.eskimo.com/~scs/C-faq/top.html>
CLC readme: <http://www.ungerhu.com/jxh/clc.welcome.txt>