jd_hupp
join:2003-08-02
South Bend, IN
| Downloads stall with large files
I seem to have a consistent problem with stalling out of large downloads. A speed test shows normal results for me in the range of 1.3Mbps download and 300Kbps upload. But right now I'm trying to download a 250MB Adobe Acrobat 8.0 trial, and it goes 30MB and stalls. I cancel and restart the download and it picks up where it left off but stalls after another 25MB. Same drill and I get another chunk. I often experience this with large downloads. Often the download will resume on its own if I wait long enough (5-10 minutes).
My usual machine is a Win XP P4 1.7GHz with 1GB and plenty of free hard drive. Speedstream 5100B modem (several years old) and TrendNet TEW-432BRP router. I'm using inline filters and hardware PPPoE with no SBC/AT&T/Yahoo software installed.
The problem occurs with or without the router in place. Right now I'm also seeing it on a Win 98 machine running behind the firewalled router without any software firewall, anti-virus or anti-spyware running, so it does not seem to be an issue with security software.
The problem occurs with IE 5, IE 6 or Firefox 2.
Anyone recognize this phenomenon? |
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nwrickert
sand groper
Premium,MVM
join:2004-09-04
Geneva, IL
 ·AT&T U-Verse
 ·AT&T Midwest
| This can be caused by line errors. The line errors cause packets to fail. Sometimes you reach the retry limit, and then the connection stalls.
Usually this shows up on smaller downloads than you are seeing. The larger the packet, the higher the probability of a problem with that packet. But you get to max sized packets with even modestly large file downloads.
The fact that you only see this on 30Mb or so downloads suggests that your line problem is relatively minor. Statistically, it is more likely to affect a larger download.
If you have not set your MTU to 1492 (or smaller), then you could try that.
That's my best guess at a diagnosis.
I have also come across a similar problem, but with the stall occurring always at exactly the same position in the file. My conjecture is that some bit string in the transmitted date is triggering a line problem (maybe a wierd echo). But that does not seem to be your problem. |
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jd_hupp
join:2003-08-02
South Bend, IN
| Max MTU is already set at 1492 in the modem's PPPoE setup. Do I need to set MTU anywhere else under Win XP?
Interesting about the line errors idea. If a packet failure retry limit causes a stall, does it then restart again automatically after 5-10 minutes (which is what I'm seeing in this current huge download)?
Thanks for your help! |
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nwrickert
sand groper
Premium,MVM
join:2004-09-04
Geneva, IL
·AT&T U-Verse
·AT&T Midwest
| If it restarts from the beginning, that's something your download client is doing.
If it resumes, that's probably tcp error handling. It works on ACKnowledgements. Your system periodically sends an ACK to indicate what it has received. The sending system resends packets that you haven't ACKed. I think the time interval between retries increases.
You could also be having problems with a funky router between you and the server. I have seen a connection stall for several minutes, with an intermediate router missing a routing information update (or some similar failure). If it stalls for more than 15 minutes, the connection is probably going to be closed/reset by your system. This might be operating system dependent. |
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jd_hupp
join:2003-08-02
South Bend, IN
| To clarify about restart/resume: I mean that the download simply stalls, with the download window remaining visible but downloading not proceeding. Then after 5-10 minutes it may show that downloading is making further progress. Although, as you note, if it stalls too long, then I get an "operation timed out" error and the download is terminated.
If I understand, you would guess that the problem is caused either by 1) line/packet errors that hit an absolute retry limit or a lengthy delay due to increasing time between retries, or 2) a funky router somewhere along the current route (a router which I apparently get frequently, since this behavior with large downloads is common for me). |
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nwrickert
sand groper
Premium,MVM
join:2004-09-04
Geneva, IL
·AT&T U-Verse
·AT&T Midwest
| That about sums it up.
If you get that often, with many different servers, then the problem is close to home (the part common to all routes).
If you are connecting via WiFi, then I guess wireless inteference might cause similar problems. |
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jd_hupp
join:2003-08-02
South Bend, IN | This is a wireless + Ethernet router, and I am connecting by Ethernet.
Thanks for helping me to understand the likeliest causes. |
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