Big Downloads pausing

[banger]

Just got my Billion 7800 today, replacing a Speedtouch 546v6. Using the speedtouch I used to get solid download graphs on DU meter from good servers. But after swapping to the Billion big downloads seem to pause for a second then continue. Currently connected on LLU to Broadcom Linecard. Are there some settings on the billion to stop this. Have updated MTU to 1500 to match the speedtouch but problem still occurs. eg a 100 mb file will pause twice.

[banger]

http://www.flickr.com/photos/banger_this/6478924725/

Here's a picture of DU meter downloading SP3 for XP. Note the gaps how can I stop this didnt happen with my speedtouch.

Here's another example

http://www.flickr.com/photos/banger_this/6479013547/

[banger]

After googling came accross another forum, http://forums.whirlpool.net.au/archive/1533529 and apparently it is a known problem. Be interesting to see if anyone else on here is suffering this as it's not easily spotted. Also effects 7800N.

[banger]

Well it went back for an exchange to Broadband Buyer, but they wouldnt exchange it as their testing said the problem would not be resolved. So have asked for a refund and bought another from Amazon. Strange BB Buyer were adamant an exchange would not fix the problem. They seem to be selling like hot cakes.

[banger]

New hardware same problem. Have tried every option I can think on the GUI but no difference. If I use multiple streams for downloads on servers that support it the stall isnt noticeable as only one out of eight streams times out. Where it is noticeable is 3 megabit HD single video stream, which causes buffering because of the 1 second stall in the stream. Still working with Billion to solve.

[banger]

Still suffering this. Main problem is streaming HD video at around 3.5 mbps. Download pauses cause stalls in videos which is annoying for such an expensive router. I have plugged my Speedtouch into the Ewan port and no stalls but the speedtouch has a habit of rebooting at crucial times.

I'm convinced this a modem firmware problem as the speedtouch connected to Ewan works fine when used as a modem. Have downloaded Wireshark and discovered what I think is the problem. I am getting "TCP Window Full" which causes the download to stop until the server buffer is cleared. Why I dont know. Wouldnt think 19 mbps was too high a speed for this router. Come on Billion sort this out.

[tinytim]

Just a very wild guess but it wouldn't be anything to do with "Jumbo Frames" would it?

The Billion only has a fixed size of 6k (others might be fixed at 9k) and if that didn't match your network adaptor then who knows what might happen.

[banger]

Turning Jumbo frames off does slightly improve the situation, eg less pauses but not a total fix. But then again I can connect the speedtouch to Ewan port and run it as a dumb modem and this cures the problem.

[banger]

Just discovered turning Jumbo frames to 1500 slows my LAN to a crawl, about 10 mbits, and it just reduces the amount of pauses anyway. One card has a max frame of 4k and the other 9k. I presume the Jumbo frame should be smaller than the 6k on the Billion.

One thing I cant understand is that if I have two downloads running, one will pause for a couple of seconds but the other will keep running as if nothing had happened. Not understanding TCP may explain my puzzlement. But according to the Billion Chinese Engineer the router pauses the network to defrag memory. This doesnt make sense as the router keeps going with the other download.

[banger]

It seems I am not alone, another user on a different ISP with a 7800N has noticed a similar problem with big files pausing.

http://forums.thinkbroadband.com/dslrou ... 7800n.html