LLQ (lower latency queing) worth?

Discussion in 'Tomato Firmware' started by quisp65, Jan 2, 2010.

  1. quisp65

    quisp65 LI Guru Member

    Would LLQ (lower latency queing) from Cisco be able to do anymore for me than a tomato firmware. The node will be running my Dads WOW and my Slingbox which will be piping 1Mbps IPTV overseas. It's a 10/2 Mbps Charter node. The reason for the QOS is to keep my Dads WOW latency low when they are both running. Anyone know anything about LLQ?
  2. TurtleFang

    TurtleFang Addicted to LI Member

    LLQ is just QOS. Some packets are given higher priority than others, there is no magic.

    I use tomato's QOS to balance online gaming (mostly MW2) and bit torrents on my home network.

    With it turned off I lag like crazy while gaming. Turn it on and you wouldn't even know I was using the network for anything but gaming, no lagging at all.

    And tomato is way, way easier to configure and monitor than an IOS based router. I had a 871W at home and replaced it with an Asus 500PGv2 running USB tomato. The 871W doesn't have a GUI to monitor QOS, nor can the USB slot be used for anything other than booting an image or using a secure token (ie no NAS support at all).

    Hope this helps,
  3. Toastman

    Toastman Super Moderator Staff Member Member

    Keeping it simple, Cisco's popular congestion control system know as "Class Based Weighted Fair Queuing" did not take into account the need for low jitter / latency requirements of VOIP etc. but essentially, it shared out the bandwidth fairly between applications. So LLQ was their improvement to allow strict priority queuing. You could therefore compare it to Tomato's class-based priority queuing system, but as Turtlefang says, Tomato's is more configurable and much easier to use.

    You may have a conflicting situation there with both IPTV and VOIP on the same line, though. You'll need to get up to speed quickly or he'll start throwing a wobbly ...
  4. jsmiddleton4

    jsmiddleton4 Network Guru Member

    When you guys talk like that it makes me feel all funny inside like a school girl getting her first kiss....
  5. karogyoker

    karogyoker Addicted to LI Member

    Use Victek's mod and limit bandwith.
    This could be my motto, haha.

    QoS is useless when you need really low pings in game while the others are downloading porn and stuff via bittorrent and ftp and so on.
  6. Toastman

    Toastman Super Moderator Staff Member Member

    karogyoker, are you serious? That's the whole point of QOS - to allow all applications to co-exist. Sounds like you just have not configured it correctly. Read Turtlefang's post again.

    Jim, those were the days ....
  7. TurtleFang

    TurtleFang Addicted to LI Member

    Limiting bandwidth alone will do just that... Limit the available bandwidth.

    OK, so you limit a definition's (say a MAC, IP, protocol, etc) bandwidth either on a bits per second burst or a max over all value. All you are doing is capping that definition's ability to use the link. It's a race between all the various definitions/classifications up to that point.

    With QOS properly configured, even the lowest priority classification can use 100% of the available link if it's the only traffic passing at the time. That's the beauty of properly executed QOS.

    Hope this helps,
  8. karogyoker

    karogyoker Addicted to LI Member

    I have 2 PC-s, A and B.
    I start playing Quake Live on A.
    Ping = 30.
    Then I start an upload to FTP on B.
    Ping = 60-100.
    This is just unacceptable.

    I can see FTP is on low priority, and the game is on highest.
    Highest minimum upload rate is 12k. This should be enough becouse the game doesn't use more than 10k.

    There is nothing else what i can do, it is just is not working.

    I have to limit PC B's upload speed to 4k, then ping stays at 30 even if PC B is uploading.

    My connection's max upload is 20k.
  9. kenyloveg

    kenyloveg LI Guru Member

    Hi, karogyoker
    Are you sure your're not running DD-WRT? (just kidding)
    It's hard to tell if you properly configured your QoS only few information. And it's strange you only got 20K outbound, do you share connections with others?
  10. karogyoker

    karogyoker Addicted to LI Member

    20kbyte/sec (sometimes it's 22k-23k but not always so i set it to 160kbit/s (20k) in qos) outbound what i get from my ISP.
    The ADSL modem connects to the WRT54GL and two PCs to it, A and B (both wired).
  11. Toastman

    Toastman Super Moderator Staff Member Member

    If your maximum speed is 20kB/s = 160kB/s, and you set that in QOS outbound, then that is why your QOS does not work. You need to set QOS to LESS than 160 so there is room in the transmit buffer to prioritize applications. I usually set to 60-70% or so - so I'd set 100kbps. If your QOS rules are working at all, you should immediately see a big difference.

    I agree. So learn how to use QOS instead of bitching about it.
  12. karogyoker

    karogyoker Addicted to LI Member

    I have upgraded my line, so the new upload speed is 500kbit. I set 400kbit in QoS and it is now works absolutely fine. Thanks.
    (When i set to 500kbit, it was horrible)
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