Скачать или смотреть Hard Quality of Service (QoS) - 8 : Traffic Types

The concept of QoS is covered in detail in the following 3 playlists:
1 - #QoS - Explains how the quality of service (QoS) provides different levels of priority to traffic crossing the network. Discusses the need for and advantages of QoS.
   • 42 : QoS -  Fundamentals of Communications  

2 - #Hard QoS - Discusses the advantages and disadvantages of hard QoS, which provides guaranteed levels of service to network traffic.
   • 43 : Hard QoS - Fundamentals of Communicat...  

3 - #Soft QoS - Discusses the advantages and disadvantages of soft QoS, which provides priority levels (rather than guarantees) to network traffic.
   • 44 : Soft QoS - Fundamentals of Communicat...  

ATM supports different traffic categories for each type of communication.

Traffic categories are like templates, and there are different templates for each type of traffic.


Let's look at an example:
If voice traffic is transmitted, the switch detects it and then determines that it must use the voice QoS traffic category. The voice traffic category is called constant bit rate, or just CBR. CBR defines what QoS parameters are important to voice communication. These parameters include a guaranteed amount of bandwidth, a limited amount of end-to-end delay, and also very little variations in delay. While these parameters are important to voice, the traffic category templates for other types of traffic are different.

Each of the traffic classes is designed specifically to support one type of traffic. This does not mean it cannot support other types-it's just optimized for one type.


In the following scenes we will look at the four most common traffic categories: CBR, VBR, ABR and UBR.