Re: Two access points in same house

The Ghost of Thomas Jefferson <Thomas@xxxxxxxxxxxxx> hath wroth:

On Sun, 21 May 2006 07:52:41 -0400, William P.N. Smith
<news2006c@xxxxxxxxxxxxxxx> wrote:

[Gee, I'm sounding like Jeff. 8*]

You left off the trademark symbol. I should have my bad attitute
copywritten.

I have a Dlink DI-624 revc firmware version is 2.70 and a DWL-2100ap
firmware v2,00. I'm trying to test the roaming with the builtin
Broadcom 802.11g adapter that came with a HP Pavillion dv5140us.

The choice of access points don't matter much. It's the client
software that has to make the switch between access points. The way
it works is that the access point will try to retain an association
for as long as possible. On some access points, you could literally
disable the wireless client, wait a few minutes, turn on the wireless
client back on, and it will continue where it left off as if nothing
had ever changed. That's great for reliability in multipath, fading,
or interference infested environments, but not so great for roaming.
It's also a good test to see how long it will take for the access
point to just give up in disgust and try to disconnect. As I recall,
the DI-624 is somewhere near forever.

That leaves the responsibility for switching in the hands of the
client. The problem there is that most clients will not connect to a
new access point without first disconnecting from the old access
point. The client will issue a de-associate packet, and wait for a
response. If the the old access point is already out of range, it can
wait for quite a while before deciding that it's time to switch. This
time interval seems to vary wildly among wireless clients. I know
that Cisco and Intel Proset 10.x allow programming the tenacity of the
client. However, it's not very fine grained.

It's easy enough to test. Find a location where you can connect to
either of your two access points. Connect to one and then have
someone turn off the access point so that the access point does not
respond to a de-association request. Now, try to connect to the other
access point. I predict a wait of at least 10 seconds or perhaps
more. (I have an HP ze2000 laptop which probably has the same
Broadcom radio, but I'm too lazy to go out to the truck and get it.
It's raining.) In this case, fast roaming really means "assume the
deassociate request arrived and don't bother waiting for a response".

I tried changing the SSID on the access point to match the SSID of the
router late last night. At that point the laptop appeared to connect
to the Access point, but was unable to pass ip traffic at that point.
At that point the network became completely unstable, with the router
losing connection to the wan.

Naw, that's all wrong. It should work with identical SSID's. I have
customers with lots of systems with identical SSID on each AP. I
currently have 2 AP's in my house with identical SSID's. Even if you
put both radios on the same RF channel, with the same SSID, it should
work just fine. (Hopefully not in the same room or you'll have lots
of interference problems). I can't really tell what went wrong. Try
the usual remedies of check your settings,

I really like the term "unstable" as it presents the image of
impending explosion or mechanical collapse. Could you be a bit more
specific as to what happens?

I've had problems with the DWL-2100ap. Setup as a point to point
bridge, they would hang far too often. I bought them because they
supported SNMP, but soon found some of the returned numbers to be
erratic. I soon found that in order to make it work, I had to disable
ALL the advanced features (no 108Mbits packet burst, no WPA, no
802.11b compatibility, etc).
| http://support.dlink.com/emulators/dwl2100ap/html/CfgWLanParam.html
(What the h**l is "Radio Wave on/off"?) I also found that it would
work on any channel exept channel 6. At first, I though it was
interference, but it turned out to be a known bug. This was about 3
years ago and some of these bugs may have been fixed by now. However,
I had a paying customer that wanted something that worked immediately.
So, I bought a pair of WAP54G radios, removed the DWL-2100ap link, and
lived fairly happily thereafter.

Somewhat later, I decided to see how they would work as an access
point. Some of my Centrino clients would not connect with WPA
enabled. (I just noticed that the DLink web page claims Centrino
tested). After much wasted time testing a multitude of laptops, I
just gave up (again) and installed a WGR-614v3 or v4 setup as an
access point, and sold the DWL-2100ap's.

Sadly, because I have invested a lot of money in the Dlink junk,
coming to realize that their hardware is junk. I have tried to use
Dlinks support people, they are the biggest asses I have ever tried to
deal with in my 30 yrs experience in the IT field.

I've tried to avoid dispensing my personal opinion of companies in
general and try to concentrate on individual products. That's because
all the bottom of the line companies (Linksys, Belkin, DLink, Hawking,
Netgear) buy from vendors in China, Korea, and Taiwan, and just put
their plastic box and name on the product. Inside, they're quite
similar depending on source. For example, all these are approximately
the same inside:
http://www.vallstedt-networks.de/?vendors/GST_Vendors

There are substantial differences in the quality of support from these
vendors. They're all fairly bad because a low cost product simply
doesn't have enough margin built in to provide quality support. An
offer of "premium" support sounds more like extortion, so they don't
do that. The result is fairly uniformly dismal support. For example,
I recently had to ask for an unreleased firmware image from one
vendor. I tried twice asking for it directly and failed. So, I let
them walk me through a stupid script, guessing where it would end. I
was right and eventually received the necessary firmware.

However, I still remember the bad old days (late 1990's), when getting
support required a 1 hour wait on hold, and where the customers were
training the support staff. It was fairly obvious from customer
complaints that they really wanted someone to answer the phone in a
reasonable amount of time. So, we have todays support system, with
fairly quick response, but seriously lacking in quality and
experience. Since 90% of the support calls are fairly simple, the
script method offers the greatest benifit for the greatest number (at
the lowest cost). Call them with anything that requires experience or
knowledge, and the script method just doesn't work.



--
Jeff Liebermann jeffl@xxxxxxxxxxxxxxxxxxxxxx
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
.

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