Downloading and Browsing simultaneously issues.

wassap · 3 Mar 2009 at 10:12

Hi Guys im hoping someone can help me, im currently on VM 20mb BB, I seem to be having problems, when I dl stuff via Newsgroups, browsing becomes stupidly slow, nigh on unusable to be frank.

Im getting good speeds via NG 22mb to be precise, I run the latest VM modem with a linksys wrt54g router, and the main pc is harwired to the router, and rest of the computers are wirelessly connected.

Has anyone any experience of anything similar?

Cheers for any advice.

G J · 3 Mar 2009 at 10:34

Sorry I don't have any experience with newsgroups, but running torrent/other programs might be the same.

On my machine with my torrent program or any program that takes all the download speed it can get is going to have an effect with normal browsing, slow loading of pages/pages sometimes refuse to load etc...

Also i've read that dedicating too much upload bandwidth with some applications can also cause these problems, it used to actually make my wireless router reset itself.

Try adjusting the settings with the newsgroup program if thats possible

tolien · 3 Mar 2009 at 10:36

If you're maxing out your connection it's going to make everything slow...

Rabtech · 3 Mar 2009 at 10:38

Cap your dowload speed slightly, set it to something like 2200KB/s or 2048KB/s - should free up enough bandwidth for smooth browsing.

wassap · 3 Mar 2009 at 10:48

Ive tried throttling the speed to 15mb and its still bloody slow, i wonder if the router is on the way out?

Ive dropped it right down to 10mb and its just usable now.

PESolution · 3 Mar 2009 at 10:58

I have the same speed connection as u, the same router, and also download using newsgroups while browsing at thwe same speeds. If you limit your connection count on your newsgroups to no more than say 3-4 then you shouldbe fine. If your hammering your newsgroups with about 10-20 connections then your poor browser isnt getting a breath..

NathanE · 3 Mar 2009 at 11:19

You can have 1,000 connections but if you've capped the software to only download at 10Mbit and your connection is 20Mbit then that will still leave 10Mbit for web surfing... which is more than enough.

I often download stuff on BitTorrent and I just set my software 100KB/sec below my maximum line rate (14Mbit). I also have a perma-cap of 5 to 10KB/sec upload (but this shouldn't matter on Newsgroups). I find web surfing to be perfectly fine...

I would hazard a guess that something may be wrong with your network configuration and/or router.

Rabtech · 3 Mar 2009 at 11:50

NathanE said:
You can have 1,000 connection *snip*

...and most residential routers wouldn't be able handle that many connections and without causing major speed/packet loss issues.

However I agree that this is going towards a router issue as most newsgroups providers would only let you have upto 10-20 connections, which should be easy enough for routers to handle.

If your on cable, have you tried connecting the cable modem directly to the machine and downloading/browsing. You could at least see if your router is causing the issue.

rz30 · 3 Mar 2009 at 13:01

As said before if you have too many connections then something like the TCP buffer or stack gets filled up and there is no room left for any more TCP connectivity, or it beomes very slow. It's something alone those lines, just think in terms of buffers(bit like cache) and you are overflowing them with too many connections, hence there is no room left for yout http tcp/ip requests.

NathanE · 3 Mar 2009 at 13:08

Rabtech said:
...and most residential routers wouldn't be able handle that many connections and without causing major speed/packet loss issues.

Dunno. My cheap £30 Speedtouch 546v6 supports like 2500 connections on its NAT table.

Even then, once exceeded it just prevents further new connections until some of the old ones are disconnected/reset/timeout. Shouldn't ever cause packet loss or speed issues. It's just a memory thing, not really processing power related. Each connection requires a small'ish entry in the NAT table. I suppose a point could arrive where the router no longer actually has enough memory to store-and-forward packets. But that should be exceptionally rare considering the TCP windowing mechanism was partly designed to prevent overloading of routers.

I say "connection" but really they are "sessions". Because even UDP (a connectionless protocol) has entries in the NAT table.

Rabtech · 3 Mar 2009 at 13:10

NathanE said:
Dunno. My cheap £30 Speedtouch 546v6 supports like 2500 connections on its NAT table.

Some routers handle more connections and refresh the NAT tables like they should. However I've seen lots of Netgears and Belkins for example killed by too many simultaneous connections (usually torrent programs).

When I say killed: the router goes slow, new connections take a long time, YES packet loss. Usually the only solution is a power cycle or soft reboot. It is down to badly programmed firmware though imo as my WRT54GL w/tomato can handle 4192 connections fine.

Skidilliplop · 3 Mar 2009 at 13:15

rz30 said:
As said before if you have too many connections then something like the TCP buffer or stack gets filled up and there is no room left for any more TCP connectivity, or it beomes very slow. It's something alone those lines, just think in terms of buffers(bit like cache) and you are overflowing them with too many connections, hence there is no room left for yout http tcp/ip requests.

I think what you meant to say there was, router CPU load caused by routing and NAT requirements in both directions for each connection. The buffer is a staging area for data waiting for the CPU to deal with it. IF you have a decent CPU then your buffer usage will be low.

This sounds like you need to setup QoS on the router to manage the minimum bandwidth available for web traffic and the priority given to connections.

wassap · 3 Mar 2009 at 16:25

I'll try the direct connection from the modem to PC.

Mind I do have 20 connections set on my news client.

hohum · 3 Mar 2009 at 18:22

You may be hitting the O/S security limit for TCP connections (only allows a limited amount within a certain space of time). If so, then that would probably explain it - your web browser would be unable to open new connections easily.

TCP/IP has reached the security limit imposed on the number of concurrent TCP connect attempts.

Check event viewer.

rz30 · 3 Mar 2009 at 20:27

hohum said:
You may be hitting the O/S security limit for TCP connections (only allows a limited amount within a certain space of time). If so, then that would probably explain it - your web browser would be unable to open new connections easily.

Check event viewer.

Beat me to it

I just learned this today as well.