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Is it normal for an RT-N16 to choke with 500 uTorrent connections?

Discussion in 'Tomato Firmware' started by Gaius, Oct 26, 2012.

  1. Gaius

    Gaius Networkin' Nut Member

    I regularly have my RT-N16 with Shibby's Tomato disconnect when downloading a torrent and I'm wondering if this is normal. Are there recommended settings for torrent clients with this router or is there something that can be done with Tomato settings to stop the router from disconnecting when using torrents?

    I would imagine that the default settings for uTorrent wouldn't be out of the question for the RT-N16 with Shibby's Tomato but even downloading a single torrent with a lot of seeds will regularly result in a disconnection that comes back to normal 3 or 4 minutes later.

    And yes I'm the only person using torrents. I live alone.
  2. koitsu

    koitsu Network Guru Member

    I haven't had any such problems with my RT-N16 router running Toastman builds (for quite some time), and using uTorrent 2.x and 3.x on Windows XP Pro SP3 (with TCP stack driver (tcpip.sys) modified to support a very large number of half-open connections). I've had literally 900-1000 concurrent TCP sessions going (doesn't matter if it's a seed or a peer) without a single problem. I do not use any form of QoS, and I do not use wireless.

    One thing I will state is that in uTorrent I rate-limit my upload speed to about 60KBytes/sec. My Internet connection (Comcast) is rated for 50mbit/sec down / 10mbit/sec up.

    I can imagine that if you're completely saturating your network interfaces (either PC-->router, router-->DSL bridge or cable modem, or DSL bridge or cable modem-->ISP) then you're going to see connections drop off and some "strangeness" happen given TCP behaviour ("this handshake is taking too long, f*** it, TCP RST...")

    I can't help other than provide the above information.
  3. Gaius

    Gaius Networkin' Nut Member

    That's probably what my problem is. I keep my upload at 80% of my upload bandwidth. Might drop it to 50%.

    I don't understand why it should be a problem however, seeing how powerful the RT-N16 is.
  4. EpsilonX

    EpsilonX LI Guru Member

    Where did you check this number..?
    In uTorrent..? or in Tomato's Conntrack..?
    Cable or DSL (modem as bridge)..?

    When I move to 8Mbps/512kbps DSL (previously cable), my WRT54GL dropped all connection when my bandwidth are 90% utilized (as per QoS setting limit)...
    I only set uTorrent to use max 60 global connection...
    When I check in Conntrack, turn out that the router is opening around 4000 connection, and the number was increasing quickly (100 in about 5 seconds)...
    The router was running out of memory and CPU usage is high, eventually it shuts down services...
    Without uTorrent running, everything is fine (the problem occurs quite randomly)...

    Currently using RT-N15U and everything is fine...
    Weird thing is, I never see the connection increases that quickly anymore...
    Firmware problem..? Maybe...
    My household maxed out around 400-500 connection, and no problem here...
    Try to check the connection number, CPU and memory usage...
  5. Monk E. Boy

    Monk E. Boy Network Guru Member

    Personally I set connection timeouts to artificially low numbers, as low as they'll go w/o causing problems (which, for me at home, means running as low as 10% of the default values, though at work I'm less brave and never go below 50%).

    I would guess one of two things are happening:
    1) You're overflowing conntrack. Setting the timeouts lower should help, because I guarantee if uTorrent says it has 500 connections open then it's tried to open 5000 or more connections. Until those connections expire then Tomato's trying to manage all of them.
    2) You're overflowing QoS buffers. Setting the connection bandwidth values lower would help this.

    Ideally I would love to wholly rely on QoS but Transmission is still configured the same way it was before I discovered Tomato (years ago) with connection and bandwidth limits in the application to prevent DD-WRT (on a WRT-54G) from exploding. On the rare occasion when I've experimented and removed all limits, the router didn't explode, it worked perfectly fine for other traffic, but BT traffic was squelched so badly that transfer rates were all over the map.

    Since I know what the limit is, and I'm the only one using BT at home, I just set the client to a figure under that number, so that if QoS comes in and says it needs to drop me down to the minimum (guaranteed) bandwidth them it can start bouncing transfer rates but otherwise it'll run smoothly.
  6. jinjorge

    jinjorge Networkin' Nut Member

    just curious... why rate-limit your upload speed?
  7. koitsu

    koitsu Network Guru Member

    For two reasons: 1) SLA/TOS reasons, 2) do not care to have my entire connection saturated both directions (down and up), given the handshaking nature of TCP. I do not care to prioritise packets (make use of QoS) either.
  8. eahm

    eahm LI Guru Member

    I am going to be the only one to say it but this router sucks.

    I mainly test routers with torrents and this one it crashed with 3-4 of them. I've tested it maybe two years ago and I don't want to say it's only hardware but mostly it is. Even my least favorite brand for p2p crashed after the N16: NETGEAR (I believe it was the WNDR3700).

    If you want to guy an N16 buy an E3000 or an E4200v1, if you want to best yet IMO buy an N66U.

    I've used the E3000 for business for years but I am switching to the E4200v1 for its awesome price and because LAN/WAN - WAN/LAN is so much better. Still, for homes, the best one is the N66U.
  9. Toastman

    Toastman Super Moderator Staff Member Member

    I have a great many RT-N16's in use as you know, and I have not experienced any problems with them at all. All my installations usually limit at around 1,000-1,300 connections using fast expiration times in Advanced/Conntrack. At my location, I currently have about 170 users, and I generally have anything up to 90 people online together. Usually around 20 of them will be using uTorrent etc. Download is of the order of 500GB+ per day even after QOS reduces the amount of downloads by P2P.

    The router QOS has to deal with all that, which it does without difficulty.

    If yours doesn't, then I would say that you have something wrong with your particular setup.

    I have used an E3000 briefly under tha same conditions, but I would most definitely not like to rely on that router.
    koitsu likes this.
  10. koitsu

    koitsu Network Guru Member

    My own experience (already documented as well; see comment #2) backs up Toastman's statements as well, though his RT-N16s in the field are handling much higher loads than mine.

    Most of the issues I've seen reported with them turn out to be software-level problems in the firmware (people turning on features/etc. that might not be as stable/reliable as we hope), and not "problems with the router". Wireless drivers (which are binary blobs -- we have no control over if they cause problems) are also known to be a problem source.

    In fact, I would go so far to say the RT-N16 is by far better than the E3000 considering how the E3000 models kept overheating (here's more evidence: #1 and #2 -- note the lack of vendor-supplied heat sinks). So seeing someone recommend an E3000 over an RT-N16 is shocking to say the least (my personal opinion: it borders on FUD).
  11. lefty

    lefty Networkin' Nut Member

    The RT-N16 is an ok unit, nothing over the top as made out to be, many under spec'd units out did it in the smallnetbuilder tests, even the linksys wrt310n out did it in wireless performance which is a VERY under spec'd unit compared to the RT-N16.


    Its an attractive unit because of its specs, made it out to be somewhat of a modder's dream machine, but as far as its performance is/was concerned, many found it to be not so choice. I have one now that sits in my closet doing nothing for this same very reason. Perhaps the hardware specs and features gave it somewhat of a placebo effect, but research companies that put it under tests found that it performed very much under the expectation that it would out do some lower spec'd units, which it in fact did not.

    I wouldn't go so far as to say the RT-N16 sucks, but atleast with my own findings, i found alot of less priced/less spec'd units out performed it.
  12. Monk E. Boy

    Monk E. Boy Network Guru Member

    Personally I suspect "research companies" unless they fully disclose all sources of their funding. There's a very large tendency for "journalists" to let the tail wag the dog. Otherwise they can (mysteriously) recommend the vendors that gave them the largest amount of funding.
    koitsu likes this.
  13. lefty

    lefty Networkin' Nut Member

    Yes, its ok to suspect "research companies", but as i noted in my last sentence, i am going off of my own findings with it, and my funding is coming from good ole manual labor. Also to note, most people i know that have/had the RT-N16 have since moved away from those units, many of them are using either the newer RT-N66U or some other unit entirely, why? Because they wanted something better.. which in itself speaks volumes. As i said, i don't think the RT-N16 sucks, but i do think there are many other alternatives that are much cheaper and lower spec'd and run cooler etc. that are much better performance wise.

    And oddly enough, this thread has turned into a discussion on whether the RT-N16 is a good unit or not, which all this honestly is irrelevant and opinionted, but one thing we all can agree upon, tomato makes these units a much tastier treat, for that i thank all you guys. :)
  14. Monk E. Boy

    Monk E. Boy Network Guru Member

    I wonder how you would describe the difference in experience such as mine and Toastman's to yours.

    Do you think we're lying when we say we have hundreds of devices passing through our routers without trouble?
  15. Toastman

    Toastman Super Moderator Staff Member Member

    Let's just put an end to pointless discussions. Everyone's opinion is different. The RT-N16 is now an old and as far as I am concerned, a "trusted" unit that I know I can rely on 100%. Some later devices, I don't know and some I do know and I can't trust. At the moment, because for me, reliability is far more important than having the latest model, my preferred option is still to buy these units for the routers and to use the WRT54GL for the AP's. Wireless "N" is completely useless for use as an AP in apartment blocks, I have little or no interest in it. With what I have, I have pretty much 100% uptime and no weirdness, none of the problems that other people seem to report every day, and that is the aim of the firmware I release. It's for access control, QOS, and routing ... period.

    Interestingly, last time I checked, there have been in excess of 75,000 downloads of this firmware since January 2012. When all is considered, the vast majority of people have no problems.

    I would point out that I don't use the VLAN builds myself, and still regard them as experimental. The Multi-SSID particularly so. I can't even remember the last time the routers rebooted unless I did it myself.

    Soon the RT-N16 will no longer be available and I will turn to something else, and I will then use the fastest and best spec'd router I can find at that time and test it thoroughly before committing to it, as it will have to last another 2-3 years before the next upgrade.

    As far as my own opinion, so far there has been no "quantum leap" in the hardware specs of most routers, rather, the increased use of SOC chipsets has brought a lot of problems. There are signs of some moves away from this trend to produce better routers, which is nice to see. Routers need to be able to handle 100Mbps+++ connections now running full QOS - not by smoke and mirrors (Fast NAT etc) ...

    I would hope to see 1.2 - 1.5GHz devices soon.
    koitsu likes this.
  16. lefty

    lefty Networkin' Nut Member

    Your experience is yours and Toastman's experience is his and, mine is mine, that's how i describe it. Did anyone say you were lying? You are entitled to your opinion as anyone, but with this type of retort, you are acting as if no one else is entitled to any opinion if it doesn't back up your experience with the RT-N16. Which is very incorrect..
  17. Monk E. Boy

    Monk E. Boy Network Guru Member

    You are entitled to an opinion, but there is a difference between stating an opinion and stating facts. Claiming that the hardware is incapable of X or Y because it's too old or slow isn't really stating an opinion, its trying give your opinion the weight of fact. What I saw from you were statements of fact, which is why I got rather upset that you were basically calling everyone who's experiencing zero problems with an RT-N16 a liar.

    Here's what I see. The WRT-54GL could sustain 30Mb (or more) of throughput through the unit, but would get substantially less if configured incorrectly. The hardware was so borderline that it didn't tolerate any foolishness at all - it didn't take much to bring the entire house of cards down. The RT-N16 has far more capable hardware, so as a result there's more leeway for what's going to be tolerated and what's not, but there's still configurations that are going to have problems. And so it goes down the line, with faster, more capable hardware better able to tolerate configuration decisions.

    It isn't just consumer class routers here, when you've got an older Cisco rackmount router it doesn't take much to throw an entire wrench into the works, while some of the newer Cisco rackmount routers can do just about anything and it still will just laugh and humor you. The more you spend the more you get, but part of what you're getting is hardware tolerance for wetware ignorance.

    That being said, there is absolutely no way I'm going to reward Cisco for their cloud firmware fiasco (replete with a remote kill switch) by purchasing their consumer class hardware. The only way they're going to learn is by withholding funds, because so long as those funds keep coming in they'll just keep ignoring complaints. So long as there are other - perfectly reliable - options available, then I'll keep using them instead.

    I will also say that the RT-N16 is right at the limit of what I'm willing to pay for a consumer class router, so anything above that point is nice but no thanks. Especially since the RT-N16 in my experience works perfectly fine and with rock-solid reliability.
    koitsu likes this.

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