Airport Dropping Signal & Bittorent clients, A connection?

Filed under pure, wild speculation”¦

Many Mac Pro’s since Leopard are experiencing interment signal drops with their Airport Extreme wireless cards. This issue was first brought to my attention only after I lugged my seventy-pound monster three blocks and hoisted it up on the counter of the Genius Bar.

“It’s a known issue with Leopard,” I was apprised and sent on my way, boat anchor in tow.

Not being content with a computer that’s price compatible with a mid-tier Hyundai, and similarly incapable of navigating the Internet with any reliability, I decided to dig into this a little bit deeper, what follows are my observations only.

#1. The problem seems to be especially active when Bittorrent clients are running.
With a BT client running I’m experiencing a drop at least every 15 minutes or so. I have segregated networks (a G only network, and a N only (5mhz) network) both are Airport networks. My Mac Pro and Macbook pro are the only two computers on the N network. When the Mac Pro drops connection the Macbook Pro does not.

The engineering answer to the problem of signal drop with a BT client active is that we’re pushing bits so hard and fast the silicon might be over heating, which causes signal loss on at the computer. I could believe this except:

#2. The problem doesn’t seem as active (with a BT client running) when the Network Preferences dialog is open.
Now this I discovered purely by accident. But If I leave my network preferences pane open (not minimized) on my second monitor, my signal doesn’t drop hardly at all. I have noticed a signal drop, but it is VERY infrequent. This suggests the problem lay in code, not in hardware.

Evil Speculation: Is there some connection intentional or otherwise between dropping wireless connections and the use of BT clients? Correlation does not equal causation but I have to wonder particularly in light of:
#3 I don’t seem to loose signal when we’re not running a Bittorrent Client.
I can’t go so far as to say that the signal drop problem doesn’t occur at all when my bittorrent client isn’t running, but after several days not running a BT client, I’ve yet to observe a signal drop. I also took steps to push bits as hard and fast as I could, downloading Linux distributions over HTTP, uploading thousands of photos over FTP. The signal seemed to stay rock solid.

So I’m back to Evil Speculation again: Is there something in code that is causing these drops to happen (at all or at least more frequently) when running Bittorrent clients?

I’d like to ask our fellow Cultists to run their own experiments. If you’re not having dropping problems fire up a bittorrent client (the problem happens with either BitRocket or Transmission) and download and seed a legal torrent (can I suggest Leander’s book?) and see if it starts happening. If you are experiencing the dropping problem: are you running a BT client in the background, does it go away when you stop?

If there are any bit-jockeys out there who can trace the actual code in memory, can we find a real connection, or is this just paranoid speculation?

Related
  • dorkhero

    Three Macs – MacBookPro (Leopard), MacBook (Leopard), G3 iMac (Panther). AirPort Extreme wireless router. G3 iMac does not have an AirPort card and is connected to the network by an ethernet cable. BT client (Transmission) running almost constantly on the G3 iMac, and every now and then on the MacBook. No drop of connection in at least the last 6 months (except for the day that I kicked the cable modem under my desk and pulled out the power cord…)

  • elimp

    Four Macs= MacBook, Macbook Pro, and an iMac all connect wirelessly to a PoweMac G4 that has internet sharing turned on. (All running Leopard)

    Now, as I read this post I laughed my ass off cuz in the last 2 days we’ve had LOTS of connection drops and guess what… I started up transmission 2 days ago. Turned it off and everything is back to normal. I too did notice that whenever I opened the network preference dialog the problem seemed to go away.

    Still, it does sound like a conspiracy theory… right?

  • António Lopes

    I believe that this is not a Mac issue (or any other operating system, for that matter). This is a router issue, so the unstable behavior is due to the differences in the routers. Some routers do not handle very well the excessive number of connections created by the BitTorrent clients and sometimes the router loses connectivity.

    I used to have this problem when I was a Windows user and the solution was to limit the number of maximum connections that the BitTorrent client accepted, thus avoiding any connectivity problems with the router.

    Now that I’m a Mac user (but with the same router), I’ve never had this problem again not because it’s a Mac, but because I limited the maximum connections on Transmission on my first use :-)

    NOTE: in the “Advanced” tab of Transmission’s Preferences, you’ll see the following note: “High connection limits slow down some routers”

  • JP

    Hi,

    Is this problem noticed exclusively with airport networks or with ethernet connection it also happens? I run transmission non-stop from an iMac with leopard connected to an wifi modem and since I updated to Leopard I noticed some network issues without find a pattern. I’ll try to search for repeated issues.

  • RaBu

    I have the exact same problem with my BT client (Transmission) on my PB with a Airport network…

  • Anthony

    I’m running Tiger on an iBook G3, and soon after reading this article i loss connection. Transmission running in the back ground. Happens frequently when transmission is running, never thought there may be a correlation. Can’t remember if i drop connection when it’s not running transimmion.

  • Alan Fleming

    Nope, sorry. You’re paranoid.

    Drops here happen pretty randomly – they happen more often when using BT, but they also happen more often when doing big transfers via other protocols – a big push to Time Capsule, or a big download from Apple for example.

    You may be close to the mark in saying that high continuous throughput could be a cause of the problem but to blame it on an inbuilt problem with BT is *way* into tinfoil hat territory, I’m afraid.

  • Matt

    I don’t use bittorrent and I get wifi drops randomly and without explanation. I use a 24″ iMac Core 2 duo. I live in a condo with lots of wifi signals around me. I have my channel set to 9. (I have changed it each time the wifi drops, so I am on my 9th drop since installing Leopard and reading the tip on setting a manual channel when in a “wifi-crowded” area).

  • leigh

    To be clear: the primary (and most likely) thesis is that the Wireless cards are likely over-heating, and dropping connections.

    The tin-foil-hat stuff come in that the problem is less apparent when the network preferences dialog is open, or when a BT client is not in use.

    On the notion of it being a router issue, that’s well and good, except the router remains up (this behavior is reported repeatedly through the message boards) it’s only the subject computer’s connection which is dropped.

    UPDATE: I did notice my first “drop” the other day when a BT client was not running, but that had been the first time in several days. My thesis that running a BT client increases your drops (either by over work, or by intent) remains.

  • PupilPhoto

    I definitely had some frustration using the current generation Airport Extreme with my 2.2 Ghz MacBook running Leopard. And yes, it definitely seemed to drop my connection more often when I was running my bittorrent client, Azureus. Lately however, I seem to have got it configured in such a way that it does not drop signals at all, regardless of BT use. I don’t know if it has anything to do with the new firmware, but I’ve seen an end to my frustration. I was beginning to think that my trusty old Linksys WRT54G was outpacing the AEBS.

  • J

    My router, for whatever reason, needs restarting daily. My Mac Mini with Leopard will reconnect to the wireless network, but won’t get an IP address until I open the network preferences pane when it will suddenly remember. My housemates XP and Vista laptops work fine, request a new address, and off they go. My PowerBook with Tiger works fine and gets a new address.

    I’ve basically put it down to Leopard being a bit weird with it’s networking. Bring on 10.5.3!

  • leigh

    Tim, you want to share any configuration details with us? did you do anything beyond firmware?

  • Mike Taylor

    Holy crap Dude. I can confirm that my MB runs fine (G + N) until I run Azureus for awhile and then the flow stops. I do not lose association with the AP, traffic just stops. I have not updated the firmware on my AE, but I did update my MB and PBG4 (although this doesn’t happen on the PB, weird) via Software Updater with the latest.

    Not cool.

  • Evan

    This has been happening to me to during torrent downloads the only difference is it is on my macbook. It also happens when I download third party apps on my ipod touch.

  • g so

    I’ve been watching hours of streaming Real Player videos studying for a nursing exam. My MB 2.2gHz c2d drops the signal every 15-20 minutes, consistently. When you are watching these streaming videos 2 hours nonstop, you notice the 5 or 6 “Loading: 5%” bar mocking you, lol.

    Is Leopard messing with the airport card? My brother’s Tiger G4 PB does not seem to have the problem, and neither does my PC tower. Just my 1 month old Macbook. Anyone have a documented, solid technology related answer?

  • Lieutenant of Barad-dûr

    try using DHCP w/ manual address i had the same issue and tried that and its fine now

  • Mat Hall

    I get similar disconnects when running Azureus, but the disconnection happens at other times too; although it *seems* more frequent when Azureus is working hard I always put it down to me being more likely to notice the connection has dropped if I’m using something that’s making constant use of it — if I’m busy with Photoshop it could be disconnecting every 10 seconds without attracting my attention, but everything going red in Azureus tends to catch my eye.

    Possibly related, but whenever I’ve tried Transmission I lose *all* network connectivity (apart from Mail) until I quit it, at which point everything springs back to life. Bizarre.

  • Dan

    I had exactly the same problem with my Tiger Running Powerbook, and Leopard-running MBP. Tiger seemed to have the connection slow, but Leopard kept dropping it.

    I also found all the same “glitches” you did, and suspect the same things. Both computers are fully-updated as far as Software Update goes, and they are both connected to the school wireless network. (G band)

    I’m also using Transmission, as you are (judging by the screenshot). I wonder if that’s part of the problem?

  • David

    I have this problem with Skype a lot (especially with conversations to folks in asia). Not tried BT. I have this with a new MacBook, not with my old 12″ powermac.
    Went to the genius bar. They said it is a problem with interactions wth the router (specifically, they say the 2wire routers from at&t are the ones they see the most problems with).
    It’s very spurious, though. I’ll go a long time with no problems, then have a whole series in a short period. Or sometime soccasional drops regularly over a period of time. It’s very strange.
    Problem seemed to be reduced with the recent software update, but it is still there.
    I’m suspecting it is a kinda “perfect storm” thing… a variety of factors are playing into the problem.

  • altopod

    I have a MacBook with a Linksys N router but not using file sharing. My connection was dropping constantly for awhile. I tried different settings on the router but nothing worked. Then it stopped happening. I noticed that two of my neighbors networks were no longer detected. I think that is what was causing the problem.

  • clifford

    Dual 867 G4, original Airport base station, Transmission as the client.

    Before I began to limit the number of connections, my connection would drop every ten minutes or so. Both limiting the number of overall connections and limiting the number of things downloading at the same time solved the problem for me — I can have a bunch of stuff running with a connection limit, or I can download one or two things with no connection limit and I’m fine.

  • Alex

    If we’re spinning conspiracy theories, does anyone recall the rumour Leopard would be including it’s own torrent engine?

    Oh come on, let’s add 2+2 and make 6.

    FWIW, Leopard was constantly dropping connection to my wifi router; I’ve gone back to Tiger and it’s rock solid even with torrents running.

  • eyespark

    I experienced this last summer on my home network running a MacBook Pro,iMac 24″, and a Airport Extreme Base Station. The drops would occur every 15 or so minutes while running Azureus and would not completely stop until I had rebooted everything. After a lot of trial and error I found that running Azureus for just 5 minutes or so would eventually lead to a drop even if was many hours later — compared to AirPort never experiencing a drop if Azureus has NOT been used since rebooting.

    I don’t know the exact cause but I did find a solution — it required 2 steps that I found floating around a couple different BitTorrent/P2P forums.

    First, they suggested downgrading the AirPort BaseStation from 7.2 to 7.1 (which Apple makes pretty easy to do). This did seem to help at least part way. Note — I am now running version 7.3.1 without problem so Apple likely fixed whatever bug 7.2 introduced with this recent update.

    Next, and this seems to be the *big* fix, I disabled DHT (distributed hash tables / distributed database) in Azureus and put reasonable caps on the number of concurrent connections. That completely fixed the problem. Why… not sure. But using DHT seemed to be the main culprit. My understanding (which is limited) is that the connection or I/O activity increases exponentially when using DHT so maybe that points to the underlying problem AirPort is having. Clearly SOMEthing gets overloaded and quits. My guess, is it’s not heat related… because just a few minutes of Azureus running DHT *seems* to trigger a drop several minutes or hours later regardless of continued use/heat… as if some sort of buffer is filling up with junk that eventually kills the connection. The only thing I’ve experienced that “seemed” similar was when the Code Red Worm was knocking out Cisco DSL routers on the Qwest network several years ago… the worm couldn’t infect Macs, but the worm incessantly probing for connections somehow overloaded the router (a tech explained it as similar to filling RAM full or errors until it couldn’t function and the fix was to reboot… like clearly PRAM on a Mac in the old days).

    Anyway, maybe this helps someone else figure out the real cause. All I know is disabling DHT in Azureus fixed my problem (along with my Base Station *not* running firmware 7.2)

  • Martin Gray

    Filtering through the hundreds of posts on this subject the problem seems to be the combination of Leopard and the macbook. Nobody seems to have a robust diagnosis and equally there is no reliable solution. What is notable is that there is no advice offered from apple which seems to be a major flaw as there are many customers suffering the same problem.
    Apple needs to sort this problem out or it is set to lose the loyalty of it’s customer base.

  • Darryl

    My issue is drops using Time Machine. I have a MacBook Pro 2.2 GHz connecting to an Airport Extreme (current generation) over 802.11g (I have some older hardware that I have not yet migrated to .11n). I have had large downloads using various clients, no problem. But since I recently put a USB disk on the Airport for Time Machine backups, I see occasional drops. It seems that once Time Machine starts, it fails after about 10-20 minutes and the whole connection is down. All it takes is a click on the network status in the tool bar up top and it re-establishes, but the backup is already aborted and has to start over. Haven’t figured out why yet.

  • mufngruf

    Running a mac dual through ethernet, I get the same dropouts with either Azureus or Transmission… sometimes it’s just a coupla seconds, sometimes it just freezes and the router and the computer have to be restarted and even unplugged (router..). The router DOES have wifi capabilities which run whenever the router is on so, even tho’ the computer connects by E’net cable, the airport may also be a culprit. I’ll try leaving the prefs open and see if it helps.
    For some consolation, whenever it happens I remember the early modem days when 1.2k speeds were considered wonderous and of the number of hours/days/weeks spent watching tiny progress bars creep funeral-pace across my monitor and praying that the computer wouldn’t crash and make me have to start all over again.
    You’d be surprised how much this helps one’s attitude towards speed and connections.

  • LeMacBacon

    Hi there!
    I’ve recently installed in my Mac Mini a Mac Pro airport extreme card to add 802.11n support to my dear mini…
    I’ve noticed the same problem. Airport drops connection when I’m running Azureus. And thanks to Mr McMullen, when my network preference is open my networks issues simply disappear ! Great solution.
    Apple, please correct this problem in the next release of Leopard.
    LeMacBacon

About the author

Leigh McMullen

Leigh McMullen leads the Advisory Services & Strategy practices for the professional services arm of one of the Big-Five firms. He has written several books that would cure any insomnia you might have, and is an avid Mac junkie.

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