What should I expect from traffic shaping?



  • I have a simple question: what is a realistic expectation from traffic shaping?

    For example, should I be able to give eMule/Bittorrent an unlimited upload speed, and still expect (near) maximum speed downloads? Should I expect good web surfing? Low ping times?



  • Yo, if set up correctly  :D



  • Okay, cool!

    So, how can I do it? I have a PIII 650 running pfSense, working perfectly as we speak. I ran the Traffic Shaping wizard and it set everything up, with P2P catch-all, DNS at high priority everything else normal, but it has not made the slightest difference. I can see the correct queues being filled up though.

    I'm on NTL 10MB broadband, which I benchmark consistantly at 9.2Mb down and 500k up. I entered these values into the wizard, and even tried values 10% lower, but nothing made any difference.



  • What exactly is the problem? You can't get better values than your line can deliver without trafficshaping and no load and you will have slightly less good results with trafficshaping when you put high load on it (speaking of pings for example).



  • The basic problem is that uploading kills my download, or vice versa.

    With Bittorrent or FTP uploads, the download speed drops from 9.2Mb/sec to around 1Mb/sec. In eMule, the opposite happens - as download speeds go up, upload speeds drop to around 70Kb/sec (that's bits, maybe 6k bytes/sec).

    I thought the point of prioritising acks was to prevent this, but it doesn't seem to work. Having said that, web browsing is a bit more usable than it otherwise would be, and ping times generally stay under 300ms.



  • Try reducing your upstream/downstream speeds in the wizard. Also set service4s like http, icmp, dns to high priority. What cpu load does your system show under high load? maybe your system is too weak?



  • Thanks hoba, I did try lowering my upload speed but it didn't help. I tried the download speed as you suggested, but that made no difference either.

    My machine is a PIII 650, it shows about 5% CPU usage on average.

    Do you think it could be something to do with the kind of packets eMule is using? Maybe they are fragmenting a lot or something, causing me not to get anything like the speed I should? NTL recommends an MTU of 1500.

    One other thing, I have noticed that NTL seems to have particularly massive queues for uploads. On ADSL, queues seemed a lot shorter and even a maximum upload couldn't kill web browsing. But on NTL, a maximum upload can cause timesouts and massive packet loss. To give you can idea, although I can benchmark 62k/sec to FTP sites, if I upload more than 12k/sec in uTorrent my downloads start to slow down. Ditto with NNTP. Is there something special I should do to compensate for this?



  • Read this thread and make sure your not seeing drops on your queues:

    http://forum.pfsense.org/index.php/topic,1384.0.html



  • Thanks sullrich, I did read that and I'm not getting drops on my queues.

    Appologies for not responding sooner, I was locked out of the forum for a while because it was rejecting connections from behind proxies.

    Does around 20-30pps for acks seem reasonable? That's with an 11kB upload speed, getting about 280kB down. 7kB/sec worth of acks. Seems about right, on an MTU of 1500. It never seems to get above 50pps, with an unlimited upload.

    PS. I think this could be something to do with NTL, but I'm not sure what.

    NTL gives you a 512kb upload, which I can max out uploading to NTL web space or Flickr. However, anything over 11kB seriously kills download speeds. That simply shouldn't happen. Does anyone have any ideas what could cause it? It's via a cable modem, so the overhead should be quite low compared with, say, ppoe. Yet, the exact same software on the same routers and PCs allowed me to upload at 40kB/sec on 480kb up ADSL without loss of download performance.


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