Quality of Service (QoS)

Finally I am going to say something about Quality of Service (QoS). QoS is becoming the need of every network now a days and one should be aware of this technology and one have to implement this in his network in order to have smooth communication. In this part of QoS I will be talking about the following few concept and slowly we will be going in dept of QoS.

 Brief History
 QoS Requirement
 QoS Deploying Methods
 QoS Toolbelt

History

Best-Effort Model was based on first come and get, means whoever comes in so they will be assigned the bandwidth, then Integrated Services comes in and that was the first QoS application which uses RSVP to reserve bandwidth for our traffic. Differentiated Services was another application which was based on or gives services on per-hop basis to prioritized traffic, more flexible than Integrated Services as we don’t need to do reservation. After this MPLS/VPN QoS comes in, then Auto QoS then QoS for security, NBAR (Network Based Application Recognition) is used by QoS for security; I will discuss NBAR in detail later on in this QoS series.

QoS Requirement

We can have traffic in our network like DATA, VOICE or VEDIO; normally data is not that much important in comparison to Voice or Video and data is not that much bandwidth hungry like video. Voice is giving priority than all other traffic including video as we should have voice clear and a bit delay in video is acceptable. Now days we having video conferencing (Voice + Video):

There are four evils of your network:

Lack of Bandwidth is when you not sufficient bandwidth available in your network for data.

Packet Loss is when you lose your data traffic because of delay or jitter.

Delay means how long it takes a packet to reach from one point to another point, For example ITU said that for PSTN the delay (one side) can be < 150 ms.

Jitter is known as Delay Variation means one packet take 100 ms to reach from point-A to point-B and another packet take 130 ms, so the variation in the delay is called jitter. We can say that in this communication the jitter is 30 ms which results in packet loss.

QoS Deploying Methods

1. Command-Line Interface (CLI)
2. Modular QoS CLI (MQC)
3. Auto QoS
4. QoS Policy Manager (QPM)

QoS Toolbelt

1. Classification & Marking
2. Policing & Shaping
3. Congestion Avoidance
4. Congestion Management
5. Link Efficiency Tools

Study this site for more about the QoS in the coming posts.

I Hope this will be informative for you

Cheers :)