Subject: RE: IETF58 - Network Status

From: "Michel Py" <[email-masked]>
Date: Thu, 13 Nov 2003 10:18:30 -0800

> Randall Gellens wrote:
> I have been consistently unable to maintain a connection
> for more than a very few minutes, usually not even lon
> enough to establish a VPN tunnel and fetch one message.
> The 802.11 coverage comes and goes; the APs seem to 
> vanish and I see nothing for a while, eventually the
> network comes back but only briefly.  This has been
> the case in every session I've attended, as well as
> tonight's plenary.  It doesn't seem to matter if the
> room is crowded or empty, or where I sit.

I have had the same issue. Not suggesting the way I solved it is the
"right" one, it turned out that when I replaced my Linksys 802.11b with
a brand new Motorola 802.11g the problem went away; there is a Radio
Shark on the third floor of City Center that sells them for $70.

If your WiFi card is a removable PCMCIA one, try to swap it temporarily
with another one; some of the older card would work fine in less crowded
environments but can't take the heat of the kind of WiFi we have for
meetings.

Michel.

---

From: "Perry E.Metzger" <[email-masked]>
Date: Thu, 13 Nov 2003 14:38:24 -0500

> Shark on the third floor of City Center that sells them for $70.

Note that getting 802.11a works even better.

Perry

---

From: Randy Bush <[email-masked]>
Date: Thu, 13 Nov 2003 14:46:59 -0600

> Note that getting 802.11a works even better.

until everybody does, and 'everbody' is twice
as many people as now

---

From: Joel Jaeggli <[email-masked]>
Date: Thu, 13 Nov 2003 13:41:46 -0800 (PST)

the map coloring problem is a lot easier with 8 non-overlaping channels.

joelja

-- 
-------------------------------------------------------------------------- 
Joel Jaeggli  	       Unix Consulting 	       [email-masked]    
GPG Key Fingerprint:     5C6E 0104 BAF0 40B0 5BD3 C38B F000 35AB B67F 56B2

---

From: "Perry E.Metzger" <[email-masked]>
Date: Thu, 13 Nov 2003 17:06:35 -0500

> the map coloring problem is a lot easier with 8 non-overlaping channels.

And indeed, it isn't even possible with just three.

Perry

---

From: Simon Leinen <[email-masked]>
Date: Thu, 13 Nov 2003 23:39:58 +0100

> until everybody does, and 'everbody' is twice

I think 802.11a should be able to support more than twice as many
users than 802.11b.  At least in the US, the band reserved for 802.11a
has more channels available than the one for 802.11b, in particular
more non-overlapping channels.  For this reason, and because of the
lack of competition from 802.11b users, 802.11a should also support
more users than 802.11g (54 Mb/s in the 2.4 GHz band).  So for
settings such as IETF/NANOG etc. this seems very attractive.

If someone knows which 802.11a PCMCIA card can be made to work reliably
under Linux (with 2.6 kernel!), I'd really like to hear about it...
-- 
Simon.

---

From: Carsten Bormann <[email-masked]>
Date: Thu, 13 Nov 2003 23:44:37 +0100

> it turned out that when I replaced my Linksys 802.11b with

Similarly, when I put a $70 Linksys WPC54G (directly supported by Mac 
OS X 10.2.8) into my Powerbook to override the builtin (Lucent-made) 
Airport card, and switched on "Interference Robustness", I got much 
more consistent network access.
I'm still losing network access now and then, and my TCP connections 
mysteriously wedge sooner or later, but I'm functional.

I would suspect that most people complaining are using the time-tested 
Lucent/Orinoco card, which is now getting a bit old.
It sure makes sense to have a deck of cards available if you really 
need the Wi-Fi.

Gruesse, Carsten

---

From: "Marcus Leech" <[email-masked]>
Date: Thu, 13 Nov 2003 18:09:52 -0500

>under Linux (with 2.6 kernel!), I'd really like to hear about it...
Atheros released open-source linux drivers for their chips and the 
corresponding reference design.

I don't know which cards use the Atheros chipset, other than ours.

---

From: shogunx <[email-masked]>
Date: Wed, 12 Nov 2003 21:13:28 -0500 (EST)

You can probably find that info at http://personaltelco.net  although I'm
not sure you will be able to take advantage of the Prism2 chipset AP fuctions
avialable using 80211b.

Scott

> under Linux (with 2.6 kernel!), I'd really like to hear about it...

sleekfreak pirate broadcast
world tour 2002-3
live from the pirate hideout
http://sleekfreak.ath.cx:81/

---

From: Iljitsch van Beijnum <[email-masked]>
Date: Thu, 13 Nov 2003 20:52:36 -0600

> mysteriously wedge sooner or later, but I'm functional.

Hm, I've only really lost connectivity a few times but I did suffer 
from hanging TCP sessions fairly consistently when sending somewhat 
large amounts of data at some times in some rooms. But in those cases 
the packet loss was double and the RTTs to the first router triple 
digits. This is with a week old Powerbook with built-in 802.11g.

---

From: Doug Barton <[email-masked]>
Date: Fri, 14 Nov 2003 01:35:05 -0800

> I don't know which cards use the Atheros chipset, other than ours.

The atheros folks are also cooperating with the FreeBSD project, so they 
are making a good commitment to open source with their products. FWIW, 
my trusty old Netgear MA401 card could barely hold a connection in 
Minneapolis, but my shiny new D-Link DWL-AG650 did a much better job. 
This is from ath(4) on FreeBSD. Not intended to be a complete list, just 
a good starting point.

      Card                Chip      Bus        Standard
      D-Link DWL-AB650    AR5211    CardBus    a/b
      D-Link DWL-AG520    AR5212    PCI        a/b/g
      D-Link DWL-AG650    AR5212    CardBus    a/b/g
      D-Link DWL-G520B    AR5212    PCI        b/g
      D-Link DWL-G650B    AR5212    CardBus    b/g
      I/O Data WN-AG/CB   AR5212    CardBus    a/b/g
      Linksys WMP55AG     AR5212    PCI        a/b/g
      Linksys WPC51AB     AR5211    CardBus    a/b
      Linksys WPC55AG     AR5212    CardBus    a/b/g
      NEC PA-WL/54AG      AR5212    CardBus    a/b/g
      Netgear WAG311      AR5212    PCI        a/b/g
      Netgear WAB501      AR5211    CardBus    a/b
      Netgear WAG511      AR5212    CardBus    a/b/g
      Netgear WG311       AR5212    PCI        b/g
      Netgear WG511T      AR5212    PCI        b/g
      Nortel 2201         AR5212    CardBus    a/b
      Orinoco 8480        AR5212    CardBus    a/b/g
      Proxim Skyline 4030 AR5210    CardBus    a
      Proxim Skyline 4032 AR5210    PCI        a

Hope this helps,

Doug

---

From: Jim Martin <[email-masked]>
Date: Thu, 13 Nov 2003 14:15:39 -0800

> until everybody does, and 'everbody' is twice
	Actually, no. 802.11a is inherently better for this sort of 
environment than 802.11b or 802.11g. Instead of having 3 
non-overlapping channels, it has 8. Also, being at 5G it doesn't 
propagate as far as the 2.4G, which for us would be a real win since it 
would reduce interference even further. Oh, and you get 54M to share 
rather than 11M to boot :-)

	I strongly encourage people to consider bringing 802.11a cards to 
future meetings!  (Note: Of course, now that I've said that, the future 
hosts will decide against deploying it)

	- Jim
	IETF 58 NOC

---

From: Tim Chown <[email-masked]>
Date: Fri, 14 Nov 2003 15:05:25 +0000

Deploy both and we can suck it and see...

---

From: Joel Jaeggli <[email-masked]>
Date: Fri, 14 Nov 2003 07:50:33 -0800 (PST)

> hosts will decide against deploying it)

5ghz unii allocations differ by country as well. in the US we have 
5.15-5.35 for indoor/outdoor and 5.725-5.825 for outdoor. japan has 
5.15-5.25 and europe has 5.15-5.35 and 5.47-5.725. I'm not sure what the 
allocation is in korea but it may well be different than that supported by 
regulatory domain A US card was built for.

I would note that the a hopeful sign is that samung is a vendor of 802.11a      
equipment.

---

From: "Henk Uijterwaal (RIPE-NCC)" <[email-masked]>
Date: Fri, 14 Nov 2003 23:08:49 +0100 (CET)

> hosts will decide against deploying it)

If we go for 802.11a, I sugggest that we ask a vendor (or two) to come
with a pile of cards that people can borrow for a few $$ more than the
manufactuiring price, and can return after the meeting, or not.

Henk

------------------------------------------------------------------------------
Henk Uijterwaal                             Email: [email-masked]
RIPE Network Coordination Centre            WWW: http://www.ripe.net/home/henk
P.O.Box 10096          Singel 258           Phone: +31.20.5354414
1001 EB Amsterdam      1016 AB Amsterdam    Fax: +31.20.5354445
The Netherlands        The Netherlands      Mobile: +31.6.55861746
------------------------------------------------------------------------------

That problem that we weren't having yesterday, is it better? (Big ISP NOC)

---

From: Iljitsch van Beijnum <[email-masked]>
Date: Sat, 15 Nov 2003 23:03:41 +0100

> manufactuiring price, and can return after the meeting, or not.

Note that 802.11a isn't an option for everyone due to lack of PCMCIA 
ports or driver support.

Also, I don't think the troubles we had are inherent to 802.11b. In 
Vienna there were even a few more people, but IIRC not wireless 
problems to speak of. I do seem to remember there were huge amounts of 
base stations deployed there and they used overlapping channels. (But I 
may be wrong.)

I believe we had two problems the past week:

1. Congestion
2. Clients jumping to peer to peer networks

Ignoring obvious solutions to 1. such as more 802.11a and better RF 
surveying/design, I think adding some 802.11g to the mix might also 
help. If the number of 802.11g capable hosts is large it would make 
sense to put them on a separate channel (and possibly SSID) where the 
higher bandwidth allows for a larger number of clients on a single 
channel and the other channels can be used by 802.11b-only hosts. If 
the number of 802.11g hosts is small, then it would probably be a good 
idea to have the base stations in mixed mode. The g hosts can still 
achieve higher speeds this way (although not as high as in g-only mode) 
so they'll leave the channel free for b traffic a larger percentage of 
the time. Also, the RTS/CTS mechanism that is used to make the b-only 
stuff be quiet while 802.11g is doing its thing could in itself be 
helpful.

As for 2., it seems some stuff tries to hang on to the same base 
station network when the base station in use disappears while other 
implementations simply jump to the strongest network they can find, 
even if this is a different SSID (when the SSID isn't explicitly 
selected) or a peer to peer network using the same SSID. Obviously it 
would help if the clients improved their behavior, but wouldn't it also 
make sense for the base stations to simply not disappear? That would 
also solve the problem.

---

From: "Spencer Dawkins" <[email-masked]>
Date: Sat, 15 Nov 2003 19:49:57 -0600

----- Original Message ----- 
From: "Iljitsch van Beijnum" <[email-masked]>
> selected) or a peer to peer network using the same SSID.

I am not an 802.11 genius and am not trying to debug a LAN protocol I
understand vaguely on the IETF discussion list without looking at the
specs first, BUT this is approximately the behavior I thought I was
seeing, too - I happened to be running Network Stumbler, especially
Tuesday and Wednesday (just before the network hygiene signs were
taped to all the rest room doors, in a burst of fitting irony).

What I THOUGHT I was seeing was a heckuvalotta peer-to-peer
transmitters insisting they were ietf58, but (at least by the time I
noticed a problem and turned my attention to Network Stumbler) there
were also a pretty good collection of access points for ietf58 that
were reachable and active.

FWIW, if my (Dell TrueMobile) card had lost its mind and connected to
a different SSID based on signal strength, I would have expected to
see the Hilton network pop up at least once, and I never did, so I'd
be a tiny bit surprised if that was happening. It looks more like the
check was for strongest signal with same SSID, not including "is this
also an access point?" check.

Once that happened, of course, I was off into the land of link-local
addresses, etc.

> Obviously it

I had a nice conversation with one of the university NOC chaps on
Friday morning, who said a lot of the access points came up
transmitting at 1 milliwatt, which was plenty until somebody walked
between you and the transmitter. This should have been fine (just find
another transmitter, right?), but the process kept stumbling over
adjacent machines already announcing ietf58 in ad hoc mode, and (like
all great networking phenomenon these days) the problem managed to
spread because when (if?) the new machine went into ietf58
peer-to-peer mode, it's now close to other machines, so the next time
someone interrupts their signal from the access point, they home on
you, and...

Sorry I don't remember the name - hope I said "thank you" then!

Spencer