Hey, Recently ive noticed a significant reductions on my P2P connection speeds after a 'software upgrade' somewhere in BT (British Telecom). My ISP is e7even which uses BT's phone lines. I have 1Mb/256Kb uncapped ADSL but recently ive noticed i can only get speeds of around 30KB/s on transfers through DC++ and Bittorrent. Even my uploads are slugish and i cant get anythign more than 20KB/s. Im doubting this has anything to do with my setup as i have been using this software for years now getting my full speeds etc (110KB/s). I do still get full speeds when downloading from http servers etc, from websites. My question is, is it possible for ISPs to cap P2P connections but not regular connections to websites? P.S. The torrents i have been trying to dl from have 1000s of possible peers, i should be getting better speeds.
Yes, it is very easy to filter traffic based on application type or tcp port number. You basically define a QoS (Quality of Service) queue for what you want to limit and a higher level for everything else. That way you can rate limit BT but allow HTTP and FTP at full speeds. With things like NBAR, Network Based Application Recognition you can still determine traffic from a particular application even if they attempt to run it over port 80 or some other common port.
Yes but can ISPs differentiate between my traffic and therefore slow the connections to and from P2P software?
Yes, that's what I just said in my previous post. It's easy to filter P2P traffic or drop it altogether if they wanted to. BT will open certain TCP ports so any traffic using those ports they rate limit so you only get a percentage of the bandwidth. Even if you the P2P app will run over port 80 or some other common port, NBAR can still rate limit it, ie slow it down.
Sorry, i misunderstood. I use custom ports for all my P2P activity, surely that should make a difference? Is it known that some ISPs do this? What is this sort of behaviour called so i can ask my ISP if they are doing it? Thanks for your response so far.
Using different ports will not make a difference. Any network protocol analyzer will see that it is a BT packet, that information is right in the packet header. I don't know about which ISPs would do it, but I know at work the firewalls filter out all packets using BT regardless of port since the firewall is examining the packet header of everything going in and coming out anyway.
Thank you, that has cleared things up. I'll email my isp now. I hope that its just a spell of bad luck with my speeds and not that i will now be subjected to 1.5years more of poor P2P speeds, seeing as im on contract.
