Dual-WAN & Bittorrent Speeds



  • I'm using pfSense to combine two RoadRunner cable internet connections that average around ~500KB/s each. The first connection is one that I pay for, the other is a neighbor's who has agreed to allow me to wirelessly bridge to theirs. The problem I'm having is in the fluxuation of bittorrent download speeds since I've been using pfSense.

    Doing some testing, I downloaded a 722MB well-seeded file from a private site in about 45 minutes. Speed ranged from hitting the expected high speeds of the combined connections, then plummeting down to ~30KB/s and eventually getting back up into the high speeds. It repeated this for the entire torrent, and never really hit a constant speed area as most torrents usually do, which is why it took so long to get the file. Also, looking at the traffic graphs of the WAN and OPT1, the load was always balanced mostly equally, even when the speeds plummeted. Could this mean the entire internet for my area/neighborhood was the cause of this?

    I've attached a picture of the speed graph uTorrent created for the duration of the download in 30 second steps. As you can see, speeds topped out at an expected ~1000KB/s for a bit near the end. The constant wave in the graph is troublesome to me since I'm use to getting speeds that stay generally pretty consistent.

    Any insight into what would be causing this would be excellent. Thanks!



  • Can you post the graph from downloading that same torrent using only one WAN?

    With all the crap ISPs do to/with Bittorrent anymore, I'm suspect if you can consistently download regardless of load balancing setup.



  • @cmb:

    Can you post the graph from downloading that same torrent using only one WAN?

    With all the crap ISPs do to/with Bittorrent anymore, I'm suspect if you can consistently download regardless of load balancing setup.

    Hmm you seem to be onto something. I disabled OPT1 so everything was going out the WAN and found a similar 715MB well-seeded torrent and gave it a shot. Speeds got very fast (faster than I thought my single cable connection could go ~800KB/s) despite no load balancing, and then plummeted down frequently as before. (Although it never went to quite as low speeds as before.)

    The torrent downloaded in just over 25 minutes, so it does seem like its faster on just one WAN even with the constant wave of peaks and troughs. Load balancing over the WAN and similar OPT1 connection should make it faster, right?

    Any ideas what could be causing this? I know its immensely hard to duplicate something like this for proper testing. I'm thinking it could be the overall internet provider for my area, but I'm not really sure. Possibly I should try the same test connected to a non-pfSense router aka retail linksys?




  • Since both connections are on the same ISP, it's hard to say how it should behave with two WANs rather than one. With two different ISPs I would definitely expect that to be the case. With a single ISP, it's hard to say. From what your graphs show it does indeed appear your ISP is interfering with your traffic. They'll let it ramp up for a bit, then it appears likely that some traffic is being dropped which really lowers your throughput, then it ramps back up again, and repeats.



  • I agree that it seems to be some funny business with his ISP.  With a well seeded torrent, I've been able to completely saturate my home cablemodem (Optimum Online) and get 10-12mbits/sec.  With that same hardware in a dual WAN setup (1.5mbit SDSL + 1.5mbit T1), I tested the same torrent and got almost 3mbit/sec.

    Best,



  • You may be hitting some bandwidth limits by increasing your 'neighborhoods' total download bandwidth by increasing it due to using two lines instead of one. So your ISP may be kicking in some bandwith limiter now.



  • @Stoutman:

    You may be hitting some bandwidth limits by increasing your 'neighborhoods' total download bandwidth by increasing it due to using two lines instead of one. So your ISP may be kicking in some bandwith limiter now.

    Unfortunately that's not the case, as I can download files via HTTP from rapidshare at a continuous 1.5MB/s (maxing out both WANs) without problem. So maybe as familyguy hinted at above, RoadRunner is 'limiting' the bittorrent download speeds.



  • @Creighton:

    @Stoutman:

    You may be hitting some bandwidth limits by increasing your 'neighborhoods' total download bandwidth by increasing it due to using two lines instead of one. So your ISP may be kicking in some bandwith limiter now.

    Unfortunately that's not the case, as I can download files via HTTP from rapidshare at a continuous 1.5MB/s (maxing out both WANs) without problem. So maybe as familyguy hinted at above, RoadRunner is 'limiting' the bittorrent download speeds.

    That still could be the case though that you're hitting a neighborhood limit of some sort, just that it's one only limited to bittorrent. Since your download speeds didn't really improve with both WANs that is certainly feasible.


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