UPDATE 2017, most recent link technologies will transfer complete L2 ethernet frames including the FCS; that in turn means that they will effectively all inherit the ethernet minimal packet size of 64 bytes. The bottom line, if you're trying to control ingress packet flow use ingress mode, else don't. Conceptually a traffic shaper will drop and/or delay packets in a way that the rate of packets leaving the shaper is smaller or equal to the configured shaper-rate. SQM seems to be confused, my measured download speed is actually close to my configured upload speed: Depending on the directionality of the interface with the directionality towards the internet that is not unexpected; try to flip the values in the GUI and see whether measured values better match your expectation. The diffserv modes split DSCP into an increasing number of tins. To keep throughput up, the qdisc now only has the small time window from handing the last packets up to the diver and the point these packets will be transmitted at the desired shaper rate to hand more packets to the driver. Also take note of your bufferbloat rating. Likely the CPU power required for wifi limited the CPU available for other processing and the router choked. The algorithm cannot automatically adapt to network conditions on DSL, cable modems or GPON without any settings. Now optionally you can experiment play with the 85% of your speed thing. SQM QoS is a very lightweight package. By now, we hope the SQM message has been clear: stick to the defaults and use cake. Those defaults are: The default cake queueing discipline works well in virtually all situations. To use SQM in your router, use the SQM QoS tab in the web interface. This interface is usually connected to an ISP's modem. You may still find it useful to get into all the details of classifying and prioritizing certain kinds of traffic, but the SQM algorithms and scripts (fq_codel, cake, and sqm-scripts) require a few minutes to set up, and work as well or better than most hand-tuned classification schemes. As of middle of 2018 sqm-scripts will try to evaluate tcMPU for cake also. Comcast Instructions for enabling DMZ (Video Included): This can be done by plugging a PC into one of the modem Ethernet ports. Now to adjust SQM please navigate to the Network -> SQM QoS tab. In this example without load, both CPUs idle > 90% of the time, no sign of any overload ;). More recently Cake switched to triple-isolate, which will first make sure that no internal _or_ internal host will hog too much bandwidth and then will still guarantee for fairness for each host. The default piece_of_cake.qos script has a traffic shaper (the Queueing Discipline you select) and three classes with different priorities for traffic. 20 Mbit/s download / 2.1 Mbit/s upload and 19 ms latency shown in the flent summary graph. And to avoid backspill we need to make sure that the combined rate of packets coming into the upstream device (rarely) exceeds the bottleneck-link's true capacity. There have been numerous attempts at mitigating Bufferbloat, but most of these are for corporate-grade networks and are proprietary. If you have a slow connection such as less than 2Mbps in either direction and/or you regularly use several VOIP calls at once while gaming etc (so that more than 10 to 20% of your bandwidth is small packets) then it can be worth it to tune the overhead more carefully, see below for extra details. As far as I can tell the more aggressive dropping in ingress-mode automatically scales with the load and hence it should make it possible to get away with configuring an ingress-mode rate closer to the true bottleneck-rate, and actually also get higher throughput if only few bulk flows are active. After logging in, run the following command to locate and install the SQM core package with an OpenWRT interface. In this post, I will install both the SQM QoS core package and SQM QoS Luci package. Regular modems only have one Ethernet Port and no WiFi built in. An important exception to the above rules is when the bandwidth limit is set by the ISP's traffic shaper, not by the equipment that talks to the physical line. Note: As of early 2017, cake is an improvement both in speed and capabilities over the original fq_codel algorithm first deployed in May 2012. cake is in every way better than fq_codel. If you retest at dslreports and get a B+ or B rating at 92%…. In that case add “mpu 64” to the advanced option strings for ingress and egress. I understand it’s better to setup sqm on your main router that gets internet from ISP but my router from my isp won’t let me get openwrt so I setup another router connected to it in which I have openwrt. Please note that for multicore routers reading %idle gets more complicated, as 50% idle on a dual core, might mean one core is fully loaded and one is idle (bad if sqm runs on the overloaded core) or that both cores are loaded only 50%. If you want to do the work, you can read the full description at the Traffic Control HOWTO. We'll come back to the 'ingress' option a little later. The Queue Discipline tab controls how packets are prioritized for sending and receipt. Since that test will only show aggregate usage over full second intervals, but SQM operates on smaller time windows, often an observed min %idle of 10% already indicates CPU limitations to sqm. Traffic shaping is relative CPU intensive, not necessarily as sustained load. Except where otherwise noted, content on this wiki is licensed under the following license: docs:guide-user:network:traffic-shaping:sqm-details. CAKE has been my go to solution to bufferbloat for years, not just because of solving bufferbloat but also for fairer sharing of my link. In other words (and a bit simplistically) google's hosts cannot monopolise all the bandwidth from Apple's hosts (or Microsoft, Facebook, github etc) in the same way that one internal host cannot monopolise all the bandwidth. Note that most (but not all) ATM based links will exclude the FCS and hence probably do not require that setting. SQM is designed to manage the queues of packets waiting to be sent across the slowest (bottleneck) link, which is usually your connection to the Internet. CAKE looks at each data flow in turn and either releases or drops a packet from each flow to match the shapers' schedule and by dropping packets from a flow before it has built up a significant queue is able to keep each flow under control. For example VDSL modem links will have some framing overhead and may also acquire a 4 byte VLAN tag. For example, if you have measured 6.2 megabits down and 0.67 megabits up (6200 kbps and 670 kbps, respectively), set your Download and Upload speeds to 95% of those numbers (5890 and 637 kbps, respectively). If you’d like to use fq_codel instead choose fq_codel & simple.qos. If you’re a twitch streamer you’ll benefit from configuring the SQM further by following this guide: https://www.stoplagging.com/modifying-sqm-for-twitch-streamers/, Copyright © 2020 | WordPress Theme by MH Themes, Quick Start for SQM preloaded OpenWrt routers, SFFPC: Golden Field M3S (18.7L) next to Silverstone SG13 (11.5L), SFFPC: Rosewill FBM-X2 vs Goldenfield M3S, http://www.stoplagging.com/wp-content/uploads/2020/07/DMZComcastFullTutorial.mp4, https://www.stoplagging.com/modifying-sqm-for-twitch-streamers/. Use a speed test program or web site like the DSL Reports Speed Test to get an estimate of the actual download and upload values. Now to adjust SQM please navigate to the Network -> SQM QoS tab. At some point in time, these advanced cake options may become better integrated into luci-app-sqm, but for the time being this is the way to make cake sing and dance…, This discussion assumes SQM is instantiated on an interface that directly faces the internet/. Now in that Download and install package field, type luci-app-sqm and click OK. Simplistically, codel works by looking at how long a packet has been in a queue at the time it is scheduled to be sent and if it is too old the packet gets dropped. You should also check the Bufferbloat site for considerably more detail. Finally, copy/paste the entire session into your report. Also to make things even more complicated, CPU power/frequency scaling (to save power) can interfere negatively with SQM. “Internet-Egress” is the shaper instance handling traffic towards the internet, “from” the router. If you are someone like me who likes to set up his router once and then keeps running 24x7x365 without any interaction, then it might be the savior for you. With wired 110/15 there was more difference. But cake offers new options that make it the nicest and most complete shaper for a typical home network: Per-Host Isolation in the presence of network address translation (NAT), so that all hosts' traffic shares are equal. This provides good defaults. Under Queue Discipline make sure cake and piece_of_cake.qos are selected as well if not select them then Save & Apply. Choose fq_codel if you plan on using this router’s WiFi. Packets also tend to accumulate extra data or overhead the closer they get to the ISP's link. Cake now uses the true source/destination address information to create Per-Host Isolation, and dynamically distributes the available bandwidth fairly between the currently-active IP addresses. As another example, if your upload speed 6000 you should enter in 5100 under Upload Speed. This will optimize the performance of the WAN interface (generally eth0) that connects your router to the ISP/the Internet. This website uses cookies. If you ensure that traffic doesn't arrive at the modem faster than it can pass to the ISP then bufferbloat within the ISP's modem is eliminated. NAT works pretty well, too, but causes problems when shaping traffic. If you’re buffer-bloat rating is A or A+ that means it is working. The right queue setup script (simple, hfsc_lite, …) for you depends on the combination of several factors like the ISP connection's speed and latency, router's CPU power, wifi/wired connection from LAN clients etc.. You will need likely to experiment with several scripts to see which performs best for you. The “Advanced Link Layer” choices are relevant if you are sending packets larger than 1500 bytes. Install and configure luci-app-sqm on openwrt. This was tested with WNDR3700 running trunk with kernel 4.1.16 and SQM 1.0.7 with simple, hfsc_lite and hfsc_litest scripts with SQM speed setting 85000/10000 (intentionally lower than ISP connection speed), 110000/15000 (that should exceed the ISP connection speed and also totally burden the router's CPU), as well as 110000/15000 using Wifi. Whilst CAKE has some sensible defaults there are a few extra options & tweaks that can improve things further. @experts, please feel free to elaborate on which power save settings are worth exploring. It’s worth it. There are three sub-tabs in the SQM QoS page that you may configure: Set the Download and Upload speeds in the web GUI for the speed of your Internet connection. This works well on egress, but for post-bottleneck shaping as is typical for the internet ingress (the download direction) this is not ideal. If you do not agree leave the website. Instantiating sqm on eth0 (note the lack of the VLAN tags) will make sure that eth0.2 is effectively throttled to min(download_bandwidth, upload_bandwidth), as eth0 egress shaping will affect both internet egress (via eth0.2 egress) as well as internet ingress (via eth0.1 egress). ingress mode modifies how CAKE's shaper accounts for dropped packets, in essence they still count to the bandwidth used calculation even though they're dropped - this makes sense, since they arrived with us but we decided that the particular flow was occupying too much bandwidth so we dropped a packet to signal the other end to slow down.