December 2009 - WLUG - wlug.mailman3.com

Re: [Wlug] Problem with wireless access point(?)

by Frank Sweetser

On 12/31/2009 5:37 PM, Jorden Mauro wrote: >> In fact, since the 5Ghz band has 19 non-overlapping channels, as >> opposed to 3 in 2.4Ghz, you're far more likely to have two adjacent >> clear channels available, giving you the option of running a 40Mhz >> wide channel instead of just 20Mhz, and therefore twice the bandwidth. >> > > I had no idea. I'll have to tinker with my router. I should also mention that 40Mhz channels are an optional feature in the 11n spec, so not all hardware will implement it. In other words, don't be surprised if you don't see it on SOHO class hardware. -- Frank Sweetser fs at wpi.edu | For every problem, there is a solution that WPI Senior Network Engineer | is simple, elegant, and wrong. - HL Mencken GPG fingerprint = 6174 1257 129E 0D21 D8D4 E8A3 8E39 29E3 E2E8 8CEC

Dec. 31, 2009

Re: [Wlug] Problem with wireless access point(?)

by Jorden Mauro

On Dec 31, 2009, at 5:21 PM, Frank Sweetser <fs(a)WPI.EDU> wrote: > On 12/31/2009 3:58 PM, Jorden Mauro wrote: >> On Thu, Dec 31, 2009 at 8:56 PM, Frank Sweetser<fs(a)wpi.edu> wrote: >>> On 12/31/2009 3:47 PM, Jorden Mauro wrote: >>> >>>> I've never been able to find a channel free from microwave oven >>>> interference, sadly. I'm convinced my ancient microwave puts out a >>>> wide spectrum and leaks plenty. >>> >>> Between cordless telephones, microwaves, bluetooth, and neighbors, >>> the only >>> reliable channel I've found is to ditch 2.4 altogether and use >>> something in >>> the 802.11a band. >> >> That's quite a bandwidth sacrifice if you've designed your network >> for n. > > Huh? 802.11n, unlike the a/b/g operating modes, isn't tied to one > particular band - it'll happily operate in either 2.4Ghz or 5Ghz. > Some particular models only support one band or the other, but > that's an implementation limitation, not one in the spec. > > In fact, since the 5Ghz band has 19 non-overlapping channels, as > opposed to 3 in 2.4Ghz, you're far more likely to have two adjacent > clear channels available, giving you the option of running a 40Mhz > wide channel instead of just 20Mhz, and therefore twice the bandwidth. > I had no idea. I'll have to tinker with my router. > -- > Frank Sweetser fs at wpi.edu | For every problem, there is a > solution that > WPI Senior Network Engineer | is simple, elegant, and wrong. - HL > Mencken > GPG fingerprint = 6174 1257 129E 0D21 D8D4 E8A3 8E39 29E3 E2E8 > 8CEC

Dec. 31, 2009

Re: [Wlug] Problem with wireless access point(?)

by Frank Sweetser

On 12/31/2009 3:58 PM, Jorden Mauro wrote: > On Thu, Dec 31, 2009 at 8:56 PM, Frank Sweetser<fs(a)wpi.edu> wrote: >> On 12/31/2009 3:47 PM, Jorden Mauro wrote: >> >>> I've never been able to find a channel free from microwave oven >>> interference, sadly. I'm convinced my ancient microwave puts out a >>> wide spectrum and leaks plenty. >> >> Between cordless telephones, microwaves, bluetooth, and neighbors, the only >> reliable channel I've found is to ditch 2.4 altogether and use something in >> the 802.11a band. > > That's quite a bandwidth sacrifice if you've designed your network for n. Huh? 802.11n, unlike the a/b/g operating modes, isn't tied to one particular band - it'll happily operate in either 2.4Ghz or 5Ghz. Some particular models only support one band or the other, but that's an implementation limitation, not one in the spec. In fact, since the 5Ghz band has 19 non-overlapping channels, as opposed to 3 in 2.4Ghz, you're far more likely to have two adjacent clear channels available, giving you the option of running a 40Mhz wide channel instead of just 20Mhz, and therefore twice the bandwidth. -- Frank Sweetser fs at wpi.edu | For every problem, there is a solution that WPI Senior Network Engineer | is simple, elegant, and wrong. - HL Mencken GPG fingerprint = 6174 1257 129E 0D21 D8D4 E8A3 8E39 29E3 E2E8 8CEC

Dec. 31, 2009

Re: [Wlug] Problem with wireless access point(?)

by Andy Stewart

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 E Johnson wrote: > Thanks Andy. > > For clarification: > >> Then, I turned on the phone and immediately saw > the wifi come to a screeching halt. > > turned on -- Did you initiate an actual phone call (TX & RX sigs) at > this point, or do you mean that you plugged in the telephone base unit > to the power and the phone line? Hi Liz, I specifically removed the handset from the base of the telephone and turned on the handset. That allows me to hear the dial tone, which I'm sure causes a radio signal to be initiated between the handset and the base. > >> In addition, I ran kismet and sniffed the local wireless networks. I >> can see networks from 3 of my neighbors. Ch 3 is not in use by any of them. > > Tomato on my Linksys will detect nearby wireless sigs & indicate what > channel they're using, plus several more details about them. My > Linksys has about 16 MD of memory, long may it live. I have seriously considered putting Tomato on my WRT54GL but I haven't done it yet. HTH, Andy - -- Andy Stewart (KB1OIQ) Founder: Worcester Linux Users' Group Founder: Chelmsford Linux Meetup Group President: PART of Westford, MA (WB1GOF) -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2 (GNU/Linux) Comment: Using GnuPG with SUSE - http://enigmail.mozdev.org iD8DBQFLPSLLOjiraCaOTOoRAjEXAJ4u7bezzZ45bQyE07/G+0WExk+x3wCg3N7u BkCUqxGoHYW9yVJkHKeEC8g= =lT55 -----END PGP SIGNATURE-----

Dec. 31, 2009

Re: [Wlug] Problem with wireless access point(?)

by Jorden Mauro

On Thu, Dec 31, 2009 at 8:56 PM, Frank Sweetser <fs(a)wpi.edu> wrote: > On 12/31/2009 3:47 PM, Jorden Mauro wrote: > >> I've never been able to find a channel free from microwave oven >> interference, sadly. I'm convinced my ancient microwave puts out a >> wide spectrum and leaks plenty. > > Between cordless telephones, microwaves, bluetooth, and neighbors, the only > reliable channel I've found is to ditch 2.4 altogether and use something in > the 802.11a band. That's quite a bandwidth sacrifice if you've designed your network for n. > > -- > Frank Sweetser fs at wpi.edu | For every problem, there is a solution that > WPI Senior Network Engineer | is simple, elegant, and wrong. - HL Mencken > GPG fingerprint = 6174 1257 129E 0D21 D8D4 E8A3 8E39 29E3 E2E8 8CEC >

Dec. 31, 2009

Re: [Wlug] Problem with wireless access point(?)

by Frank Sweetser

On 12/31/2009 3:47 PM, Jorden Mauro wrote: > I've never been able to find a channel free from microwave oven > interference, sadly. I'm convinced my ancient microwave puts out a > wide spectrum and leaks plenty. Between cordless telephones, microwaves, bluetooth, and neighbors, the only reliable channel I've found is to ditch 2.4 altogether and use something in the 802.11a band. -- Frank Sweetser fs at wpi.edu | For every problem, there is a solution that WPI Senior Network Engineer | is simple, elegant, and wrong. - HL Mencken GPG fingerprint = 6174 1257 129E 0D21 D8D4 E8A3 8E39 29E3 E2E8 8CEC

Dec. 31, 2009

Re: [Wlug] Wlug Digest, Vol 74, Issue 14

by E Johnson

Thanks Karl, > What's humorous is the difference between the words "Default" and "default". > Most routers may allow you to log on, but subsequent packets of data may not > verify correctly, hence the speed loss. So these packets are being checked maybe more than once, to make sure they are really, really allowed to go where they're supposed to go. That's what I think was happening with mine. Luckily I managed to get a wire down to my room here, so I had the luxury of taking a break from trying to get this right. But I'll be back, since before the summertime I do want get the wireless working well in the non-wired parts of the house. If you feel like sharing sometime, I would be interested in seeing what your file /etc/network/interfaces looks like (minus the psk & stuff, of course). TY Liz

Dec. 31, 2009

Re: [Wlug] Problem with wireless access point(?)

by Jorden Mauro

On Thu, Dec 31, 2009 at 5:08 AM, Andy Stewart <andystewart(a)comcast.net> wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > John Stoffel wrote: >> Andy> There were a lot of suggestions in your email - thanks! >> >> You're welcome! >> >> Andy> I'll need time to try them out. I'll report back when I get more data. >> >> Good luck with it. > > Hi gang, > > OK, I think I have succeeded in fixing the problem. Here's what I did: > > a) reset the Linksys box > > b) picked a new radio frequency that does *not* have interference issues > with my 2.4GHz wireless telephone...(I haven't tried the microwave oven > yet...). I've never been able to find a channel free from microwave oven interference, sadly. I'm convinced my ancient microwave puts out a wide spectrum and leaks plenty. > > c) insured that the Linksys box was in Gateway mode (vs. router mode > which seems not to work for me). > > After doing these three things, my laptop with 802.11g capability can > download files off of my server at a sustained rate of 13Mbits/sec > according to iptraf, or 1.4Mbytes/sec according to sftp. This is one > laptop doing one download, no other computers on the wireless network. > This is *much* faster that what I was previously able to sustain. > > On my older laptop with only 802.11b capability, by itself, I repeated > the same experiment and saw a rate of 425Kbytes/sec according to sftp, > or 3.7Mbits/sec according to iptraf. > > With both computers downloading simultaneously, the wireless net > naturally downshifted to the lower speed. When I turned off the > download on the slower computer, the speed quickly increased for the > faster laptop. > > The aforementioned data rates have been sustained for at least 15 > minutes, where before, I couldn't do this for even 1-2 minutes. > > I think I can declare victory. Thanks for the help! > > Happy New Year! > > Andy > > - -- > Andy Stewart (KB1OIQ) > Founder: Worcester Linux Users' Group > Founder: Chelmsford Linux Meetup Group > President: PART of Westford, MA (WB1GOF) > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1.4.2 (GNU/Linux) > Comment: Using GnuPG with SUSE - http://enigmail.mozdev.org > > iD8DBQFLPDHrOjiraCaOTOoRAhGOAKDGbFyuNUwoNtBZyP8pqEA9yUUFIwCgmP4n > m+svFxGvxXhKue9emJlWjG8= > =/Mkl > -----END PGP SIGNATURE----- > _______________________________________________ > Wlug mailing list > Wlug(a)mail.wlug.org > http://mail.wlug.org/mailman/listinfo/wlug >

Dec. 31, 2009

Re: [Wlug] Problem with wireless access point(?)

by E Johnson

Thanks Andy. For clarification: > Then, I turned on the phone and immediately saw the wifi come to a screeching halt. turned on -- Did you initiate an actual phone call (TX & RX sigs) at this point, or do you mean that you plugged in the telephone base unit to the power and the phone line? > In addition, I ran kismet and sniffed the local wireless networks. I > can see networks from 3 of my neighbors. Ch 3 is not in use by any of them. Tomato on my Linksys will detect nearby wireless sigs & indicate what channel they're using, plus several more details about them. My Linksys has about 16 MD of memory, long may it live. TY Liz

Dec. 31, 2009

Re: [Wlug] Wlug Digest, Vol 74, Issue 14

by Karl Lind

Karl had posted an answer about the Linksys (under the subject line "Re: [Wlug] Wlug Digest, Vol 74, Issue 13") One comment in there I found very interesting: > Now this is going to blow your mind, but if there is ANY difference in the Workgroup name between the router and the computers, it causes the router to "restrict" bandwidth. Does this only apply to various forms of filesharing, or to all wireless traffic through the WRT54GL? I (and my housemates) are not doing big downloads, and not using Samba. Maybe one of the Windows PCs here might occasionally d/l a movie. But in experimenting with wireless here, using one or other of my Debian PCs, Tomato on the Linksys, I also thought the wireless worked rather slow, even though we have a +20MBps connection. Mostly what I was doing was browsing. Do all computers using wireless here have to belong to the same Workgroup, no matter what kind of internet traffic they're doing? If I do need a Workgroup name for the router, how do I do that? Thanks, Liz J Hi Liz What's humorous is the difference between the words "Default" and "default". Most routers may allow you to log on, but subsequent packets of data may not verify correctly, hence the speed loss. As noted by Andy, wireless always defaults to the slowest speed connected. (I seem to have a lot of neighbors that try to break in to my network and when they do at G, B or even A speed the router slows and that tells me that somethings up and I can do something about it.) Karl

Dec. 31, 2009