What is QoS?

QoS stands for Quality of Service. That is, QoS is used to make sure the quality of a particular service or services. So, what are services? services are traditionally what you offer from your computer/server. Eg. web service, mail service, FTP service, etc.

Why QoS is important?

Lets take an example to understand the importance of QoS. Lets assume you made a backup of your computer/laptop. Lets say your backup file is 50GB. This make up all your documents, images, songs, etc. Now you need to transfer your backup file to a server or to another computer. You make a FTP transfer, now its running at its maximum speed, its takes few hours to complete the transfer! So, during its transfer, can you browse Internet? Can you check your mail? You know, if try to browse, its not practical till the transfer is over, it just crawls. Worse yet, if you receive a VoIP call before the transfer is completed, other party may find its not practical to talk to you, because there are so many crackling sounds!

Why your browsing crawls? Why your voice crackle? That is due to your computer does not make any distinction between VoIP traffic, web traffic or FTP and Peer-to-Peer (P2P) (eg. BitTorrent) traffic. It treats all Internet packets the same priority and send them away through your network card or modem as an when packets arrive in FIFO fashion.

The VoIP traffic are considered real-time traffic, VoIP traffic cannot wait until web or FTP traffic to clear first. FTP/P2P traffic are called bulk traffic, that is, they flood your network interface making no room for other traffic, where as bulk traffic can really wait.

This is where the QoS is required to correct the situation. The QoS is used to prioritise the traffic. QoS decides what to clear first, what to wait. Obviously, VoIP gets the highest priority, web next and bulk traffic the last. That is, in our example, during a heavy FTP transfer, if you want to make a VoIP call, QoS makes sure VoIP traffic clear first, thereby, making no disruption at all to your voice communication. Similarly, if you want to browse Internet or check your mail during the heavy FTP transfer, QoS makes sure web/mail traffic gets higher priority, thereby, you won't notice any slow down.

How does QoS work in Tomahawk Desktop?

How the QoS is programmed in Tomahawk Desktop is, your Internet traffic path to your network interface (network card/modem) is divided into three channels. The first channel is for Real-time traffic, second channel is for interactive traffic such as web/mail, and the third channel is allocated for all kind of bulk traffic.

When Internet packets arrive to the QoS system, it first queue them under relevant channel. How does it dequeue packets to be sent out is as follows: If there are Internet packets in the Real-time channel, it clears first. As long as there are packets in the Real-time channel, the second and third channels are not processed. That's, packets in the second and third channels have to wait until there are no more packets in the first (Real-time) channel. Thereby, real-time traffic gets the utmost priority, therefore, no interruption at all to VoIP traffic!

When no more packets in the Real-time channel, QoS processes the second channel (ie. Interactive traffic channel). Packets in the third channel (ie. Bulk traffic channel) have to wait until no more packets in the first channel and the second channel. Thereby, even during a heavy bulk transfer such as FTP, provided you don't make/receive a VoIP call, if you browse Internet, your web traffic get clear first, FTP has to wait, therefore, your Internet browsing does not slow down at all.

When your computer is really free, the QoS clears the bulk traffic. This gives another opportunity to you. That is, you can share files using P2P without slow down your computer. Tomahawk Desktop now offers the feature to automatically configure your computer to share the evaluation version of the Tomahawk Desktop via BitTorrent. You can now participate to share the evaluation version of the Tomahawk Desktop via BitTorrent without any fear, you now know, it does not slow down your computer.

How to enable QoS?

There is nothing for you to configure. QoS is now a core feature of Tomahawk Desktop.

Note: QoS only applicable to outgoing traffic. That's what you can control. Its like in real life, you cannot control your incoming mail, you cannot prioritise incoming Internet traffic. You can only drop them if you are not interested. Therefore, if you make a heavy download, it can effect your VoIP communication or Internet browsing. And also note, Tomahawk Desktop only prioritise Internet traffic leaving your computer, if you are on a LAN, you need to prioritise Internet traffic also at your router.