Skip to main content

Limiting Bitrate and Network Throttling

We may limit incoming or outcoming data rates to/from our infrastructure to maintain the stability of our service for customers. Bitrate limitation is an action to limit the number of bits that can be passed through a transmission channel in a period of time. Network throttling is an intentional action to slow down transmission speed in a network channel. It is not only about limiting bitrate but also limiting the allowed number of requests in a period of time. There are several tools and techniques that can be used to apply bitrate limitation and network throttling.


Wondershaper

It is an easy-to-use tool for Linux and is already in the package repository. It can limit the bit rate that can be achieved by network interfaces in the system. We can install it by running the following command.

apt install wondershaper

We can choose an interface to have a limitation either or both on download and upload.

wondershaper <interface-name> <download-rate-in-bps> <upload-rate-in-bps>

For example, the following code will limit eth0 to 40k bits/s of download rate and 20k bits/s of upload rate.

wondershaper eth0 40000 20000

To clear the setting, we can run the following command.

wondershaper clear eth0

Trickle

Based on its manual page, Trickle is a tool to limit the download or upload rate of any applications that utilize the socket interface. We can read more information about this tool here. We need to remember that only programs with dynamic linking can work with Trickle. We can test whether a binary can work with Trickle by the following command.

ldd $(which [binary]) | grep libc.so
For example,
ldd $(which wget) | grep libc.so

If it shows the location of libc.so, it means the binary can work with Trickle. For instance, if we want to limit the download rate of the wget tool, we can use the following example.

trickle -d [rate in KB/s] wget [protocol://file-URL] 

Nginx

Nginx is actually a proxy server that provides plenty of features to help us serve our web-based services such as the request rate and bandwidth limiting capability. This feature is used to prevent DDoS attacks by preventing our server to handle too many requests. It needs a defined key to differentiate a client from another, a memory zone to keep states of all the keys, and a rate-setting that states the number of requests per second or minute. The examples are as follows.

http {
    #...
    limit_req_zone $binary_remote_addr zone=one:10m rate=1r/s;

    server {
        #...
        location /search/ {
            limit_req zone=one;
        }
        location /search2/ {
        	# if request rate > specified rate, 5 requests are queued
            limit_req zone=one burst=5; 
        }
        location /search3/ {
        	# 5 excessive requests are served immediately
            limit_req zone=one burst=5 nodelay; 
        }
        location /search4/ {
        	# 3 excessive requests are served immediately, 2 requests are delayed
            limit_req zone=one burst=5 delay=3; 
        }
    }
}

Bandwidth limiting is applied per connection while Nginx originally allows multiple connections. It means if we want the exact bitrate value to be provided for specific addresses, we can set Nginx to allow only one connection.

http {
    limit_conn_zone $binary_remote_address zone=addr:10m;
    
    # mapping for dynamic configuration
    map $ssl_protocol $response_rate {
      "TLSv1.1" 10k;
      "TLSv1.2" 100k;
      "TLSv1.3" 1000k;
    }

    server {
        root /www/data;
        limit_conn addr 5;

        location /download/ {
            limit_conn       addr 1;
            # rate limiting is applied after 1MB data is passed
            limit_rate_after 1m; 
            limit_rate       50k;
        }
        
        # dynamic configuration
        location /secure/ {
            limit_rate       $response_rate;
        }
    }
}

We can get more information from Nginx documentation.


Comments

Popular posts from this blog

Configuring Swap Memory on Ubuntu Using Ansible

If we maintain a Linux machine with a low memory capacity while we are required to run an application with high memory consumption, enabling swap memory is an option. Ansible can be utilized as a helper tool to automate the creation of swap memory. A swap file can be allocated in the available storage of the machine. The swap file then can be assigned as a swap memory. Firstly, we should prepare the inventory file. The following snippet is an example, you must provide your own configuration. [server] 192.168.1.2 [server:vars] ansible_user=root ansible_ssh_private_key_file=~/.ssh/id_rsa Secondly, we need to prepare the task file that contains not only the tasks but also some variables and connection information. For instance, we set /swapfile  as the name of our swap file. We also set the swap memory size to 2GB and the swappiness level to 60. - hosts: server become: true vars: swap_vars: size: 2G swappiness: 60 For simplicity, we only check the exi

Installing VSCode Server Manually on Ubuntu

I've ever gotten stuck on updating the VSCode server on my remote server because of an unstable connection between my remote server and visualstudio.com that host the updated server source codes. The download and update process failed over and over so I couldn't remotely access my remote files through VSCode. The solution is by downloading the server source codes through a host with a stable connection which in my case I downloaded from a cloud VPS server. Then I transfer the downloaded source codes as a compressed file to my remote server through SCP. Once the file had been on my remote sever, I extracted them and align the configuration. The more detailed steps are as follows. First, we should get the commit ID of our current VSCode application by clicking on the About option on the Help menu. The commit ID is a hexadecimal number like  92da9481c0904c6adfe372c12da3b7748d74bdcb . Then we can download the compressed server source codes as a single file from the host.

Rangkaian Sensor Infrared dengan Photo Dioda

Keunggulan photodioda dibandingkan LDR adalah photodioda lebih tidak rentan terhadap noise karena hanya menerima sinar infrared, sedangkan LDR menerima seluruh cahaya yang ada termasuk infrared. Rangkaian yang akan kita gunakan adalah seperti gambar di bawah ini. Pada saat intensitas Infrared yang diterima Photodiode besar maka tahanan Photodiode menjadi kecil, sedangkan jika intensitas Infrared yang diterima Photodiode kecil maka tahanan yang dimiliki photodiode besar. Jika  tahanan photodiode kecil  maka tegangan  V- akan kecil . Misal tahanan photodiode mengecil menjadi 10kOhm. Maka dengan teorema pembagi tegangan: V- = Rrx/(Rrx + R2) x Vcc V- = 10 / (10+10) x Vcc V- = (1/2) x 5 Volt V- = 2.5 Volt Sedangkan jika  tahanan photodiode besar  maka tegangan  V- akan besar  (mendekati nilai Vcc). Misal tahanan photodiode menjadi 150kOhm. Maka dengan teorema pembagi tegangan: V- = Rrx/(Rrx + R2) x Vcc V- = 150 / (150+10) x Vcc V- = (150/160) x 5

Managing MongoDB Records Using NestJS and Mongoose

NestJS is a framework for developing Node.js-based applications. It provides an additional abstraction layer on top of Express or other HTTP handlers and gives developers a stable foundation to build applications with structured procedures. Meanwhile, Mongoose is a schema modeling helper based on Node.js for MongoDB. There are several main steps to be performed for allowing our program to handle MongoDB records. First, we need to add the dependencies which are @nestjs/mongoose , mongoose , and @types/mongoose . Then, we need to define the connection configuration on the application module decorator. import { MongooseModule } from '@nestjs/mongoose'; @Module({ imports: [ MongooseModule.forRoot('mongodb://localhost:27017/mydb'), ], controllers: [AppController], providers: [AppService], }) Next, we create the schema definition using helpers provided by NestJS and Mongoose. The following snippet is an example with a declaration of index setting and an o

Resize VirtualBox LVM Storage

VirtualBox is a free solution to host virtual machines on your computer. It provides configuration options for many components on our machine such as memory, storage, networking, etc. It also allows us to resize our machine storage after its operating system is installed. LVM is a volume manager in a Linux platform that helps us to allocate partitions in the system and configure the storage size that will be utilized for a specific volume group. There are some points to be noticed when we work with LVM on VirtualBox to resize our storage. These are some steps that need to be performed. 1. Stop your machine before resizing the storage. 2. Set new storage size using GUI by selecting " File > Virtual Media Manager > Properties " then find the desired virtual hard disk name that will be resized. OR , by running a CLI program located in " Program Files\Oracle\VirtualBox\VBoxManage.exe ".  cd "/c/Program Files/Oracle/VirtualBox" ./VBoxManage.exe list

How To Use Protocol Buffer in Javascript

We have understood a few advantages of protocol buffer like what I've explained in my other post . Now, let's look at how we can implement it in our code. The "transpiler" tool, named protoc , supports the generation of a helper class for managing the object instance in a variety of programming languages. In this post, we use Javascript as an example and run in a Linux environment. Preparation Before we develop our code, we should install protoc for generating the helper class. Download protoc binary from the release page . Extract the content and store the directories  ( bin  and  includes ) in /usr/local  directory so that the executable binary can be accessed directly. Run protoc --help to check its manual. Install a required dependency globally to enable protoc  to generate the Javascript files by running: npm i -g protoc-gen-js . Create a proto file First, we should create an empty directory