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--- technical:ppsk-sqm [2024/08/08 06:46] – [PPSK with Bandwidth Limits] system
+++ technical:ppsk-sqm [2024/08/08 10:11] (current) – system
@@ Line 6: / Line 6: @@
 -----
 ====== PPSK with Bandwidth Limits ======
-  * All the pages on PPSK up to now did not touch much on one very important topic.
+  * On all  previous pages about PPSK, a very important topic has hardly been addressed.
-  * Once we give a user access to our network, we need a way to **manage the bandwidth** he consumes.
+  * Once we grant a user access to our network, we need a way to manage the bandwidth they consume.
-  * Both captive portal and PPPoE server has the ability to do this and it was designed with the functionality in mind.
+  * Both the Captive Portal and the PPPoE server are able to do this and have been developed with this functionality in mind.
-  * Giving someone access to a WiFi network does not automatically enable you to manage that user's bandwidth.
+  * Giving someone access to a WiFi network does not automatically allow you to manage their bandwidth.
-  * Although we offer advanced features to change a user's assigned VLAN based on their usage during a specified timespan, we still need the ability to limit the speed on a VLAN.
+  * Although we offer advanced features to change a user's assigned VLAN based on their usage during a certain period of time, we still need the ability to limit the speed of a VLAN.
-  * This is where Smart Queue Management (SQM) comes in.
+  * This is where Smart Queue Management (SQM) comes into play.
-  * SQM not only allow us to limit the bandwidth on an interface to the value we choose, it also does queue management, leaving the user with a more pleasant online experience.
+  * With SQM, we can not only limit the bandwidth on an interface to the value we choose, but also manage the queues so that the user has a more pleasant online experience.
 ====== Options for a MDU deployment ======
-  * The philosophy of RADIUSdesk is to provide a non disruptive solution that can work along other vendors.
+  * The philosophy of RADIUSdesk is to offer a non-disruptive solution that can co-operate with other vendors.
-  * The following schematic shows a PPSK solution where the client opted to use PFsense to do the NAT/DHCP and bandwidth limiting:
+  * The following diagram shows a PPSK solution where the customer has chosen to use PFsense for NAT/DHCP and bandwidth limiting:
 {{:technical:ppsk:mdu_overview_scaled.png?nolink|}}
-  * We also offer the client the option to use OpenWrt that implements SQM.
+  * We also offer the customer the option of using OpenWrt, which implements SQM.
-  * This can then be managed through APdesk.
+  * This can then be managed via APdesk.
-  * Since OpenWrt can run on various architectures or even on a Virtual Machine, it gives us even more options:{{:technical:ppsk:arrow_sqm1.png?nolink|}}
+  * As OpenWrt can run on different architectures or even on a virtual machine, it offers us even more possibilities:{{:technical:ppsk:arrow_sqm1.png?nolink|}}
+  * Lets take a closer look at SQM on OpenWrt
+====== SQM on OpenWrt ======
+The following sections are a brief summary of information from this wiki page (https://openwrt.org/docs/guide-user/network/traffic-shaping/sqm) and from our own experiments.
+===== Required Packages =====
+  * To make SQM available in OpenWrt, you need the package **sqm-scripts**.
+  * If you also have Luci on the OpenWrt device, it is recommended to install the additional package **luci-app-sqm**.
+  * This will install the Luci SQM package which is well developed and provides you with an intuitive way to apply SQM to selected interfaces via the Luci web interface.
+===== Config File =====
+  * Essentially, the SQM application in Luci manipulates the UCI-based configuration file **/etc/config/sqm** and starts and stops the SQM service to apply these settings.
+  * Let's take a look at an excerpt from the sqm configuration file:
+<code bash>
+config queue 'br_ex_v104'
+    option interface 'br-ex_v104'
+    option enabled '1'
+    option script 'piece_of_cake.qos'
+    option linklayer 'none'
+    option verbosity '5'
+    option upload '4096'
+    option download '4096'
+    option debug_logging '0'
+    option qdisc 'cake'
+</code>
+  * Some notes on this snippet:
+        * The queue discipline is CAKE. There are also other options like fq_codel that you can use if performance is an issue.
+        * The upload and download values are in kbps, so this snippet limits the value to 4Mbps (4*1024)
+        * The script to set up the SQM (based on the settings in the /etc/config/sqm file) is called **piece_of_cake.qos**.
+        * The SQM section is applied to the **br-ex_v104** interface, which is actually a bridge.
+    * Let us take a look at the /etc/config/network file to learn more about the br-ex_v104 interface.
+<code>
+config device
+    option type 'bridge'
+    option name 'br-ex_v104'
+    option stp '0'
+    list ports 'eth1.104'
+config interface 'ex_v104'
+    option device 'br-ex_v104'
+    option proto 'static'
+    option ipaddr '10.200.105.1'
+    option netmask '255.255.255.0'
+</code>
+  * Although the word //interface// is used intuitively in the /etc/config/sqm section, it can also be applied to a //device// such as a bridge.
+  * In our case, the br-ex_104 bridge has one port, eth1.104. This port receives traffic from VLAN 104 on eth1 (e.g. when a user connects to a private PSK and the dynamic VLAN assigned to it is 104)
+  * The data traffic that runs via this bridge is therefore throttled and managed with SQM.
+Now that we have covered the configuration of SQM, we can take a look at some practical commands under the heading
+===== Troubleshooting =====
+  * To start and stop SQM:
+<code>
+#You might first need to stop it before starting it:
+/etc/init.d/sqm stop
+SQM: Stopping SQM on br-ex_v104
+#Start it
+/etc/init.d/sqm start
+SQM: Starting SQM script: piece_of_cake.qos on br-ex_v104, in: 4096 Kbps, out: 4096 Kbps
+SQM: piece_of_cake.qos was started on br-ex_v104 successfully
+</code>
+  * SQM creates a matching IFB interface with the convention //ifb4-<interface>//. In this way, you can easily determine whether the start was successful.
+<code bash>
+#Real interface
+ifconfig br-ex_v104
+br-ex_v104 Link encap:Ethernet  HWaddr 08:00:27:EA:B7:D5
+    inet addr:10.200.105.1  Bcast:10.200.105.255  Mask:255.255.255.0
+    inet6 addr: fe80::a00:27ff:feea:b7d5/64 Scope:Link
+    UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
+    RX packets:0 errors:0 dropped:0 overruns:0 frame:0
+    TX packets:8 errors:0 dropped:0 overruns:0 carrier:0
+    collisions:0 txqueuelen:1000
+    RX bytes:0 (0.0 B)  TX bytes:1088 (1.0 KiB)
+#Matching IFB
+ifconfig ifb4br-ex_v104
+ifb4br-ex_v104 Link encap:Ethernet  HWaddr AA:93:EE:2A:4D:E6
+    inet6 addr: fe80::a893:eeff:fe2a:4de6/64 Scope:Link
+    UP BROADCAST RUNNING NOARP  MTU:1500  Metric:1
+    RX packets:0 errors:0 dropped:0 overruns:0 frame:0
+    TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
+    collisions:0 txqueuelen:32
+    RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B
+</code>
+  * To get stats on SQM, you can use the tc command:
+<code bash>
+tc  -s qdisc show dev br-ex_v104
+</code>
+  * This brings us to the end of SQM's section in OpenWrt.
+  * In RADIUSdesk we have taken this knowledge and created the SQM Profiles applet, which makes managing SQM in MESHdesk and APdesk a breeze.
+  * There is a special page for SQM Profiles that allows you to apply limits in no time at all.