Quality of Service

-
Quality of Service

Network Services are considered end-to-end, this means from a Terminal Equipment (TE) to another TE. An End-to-End Service may have a certain Quality of Service (QoS) which is provided for the user of a network service. It is the user that decides whether he is satisfied with the provided QoS or not.

To realise a certain network QoS a Bearer Service with clearly defined characteristics and functionality is to be set up from the source to the destination of a service.

A bearer service includes all aspects to enable the provision of a contracted QoS. These aspects are among others the control signalling, user plane transport and QoS management functionality. A UMTS bearer service layered architecture is depicted below, each bearer service on a specific layer offers it's individual services using services provided by the layers below.



QoS

QoS Architecture


There are four different QoS classes:

  • conversational class
  • streaming class
  • interactive class
  • background class


    Traffic class Conversational class

    Real Time

    		Streaming class


    Real Time

    		Interactive class


    Best Effort

    		Background class


    Best Effort
    Fundamental characteristics - Preserve time relation (variation) between information entities of the stream
    - Conversational pattern (stringent and low delay )

    		 - Preserve time relation (variation) between information entities of the stream - Request response pattern

    -Preserve payload content

    		 -Destination is not expecting the data within a certain time
    -Preserve payload content
    Example of the application   voice   streaming video   web browsing   telemetry, emails

    UMTS QoS classes



    List of UMTS Bearer Service Attributes:

  • Traffic class ('conversational', 'streaming', 'interactive', 'background')
  • Maximum bit rate (kbps)
  • Guaranteed bit rate (kbps)
  • Delivery order (y/n)
  • Maximum SDU size (octets)
  • SDU format information (bits)
  • SDU error ratio
  • Residual bit error ratio
  • Delivery of erroneous SDUs (y/n/-)
  • Transfer delay (ms)
  • Traffic handling priority
  • Allocation/Retention Priority
  • Source statistics descriptor ('speech'/'unknown')

    SDU = Service Data Unit

    • Comments

    Post a Comment

    Popular posts from this blog

    Python Programming

    -
    Image
    Python is a very simple yet very powerful object oriented programming language.  Python is developed by Guido van Rossum . Guido van Rossum started implementing Python in 1989. Python is a very simple programming language so even if you are new to programming, you can learn python without facing any issues. Interesting fact : Python is named after the comedy television show Monty Python’s Flying Circus. It is not named after the Python snake. Features of Python programming language 1. Readable: Python is a very readable language. 2. Easy to Learn: Learning python is easy as this is a expressive and high level programming language, which means it is easy to understand the language and thus easy to learn. 3. Cross platform: Python is available and can run on various operating systems such as Mac, Windows, Linux, Unix etc. This makes it a cross platform and portable language. 4. Open Source: Python is a open source programming language. 5. Large standard
    Read more

    how to free port 80 in windows

    -
    Image
    his classical situation today when I was trying to run Apache on  Windows  (Basically the  WAMP  package called as  vertrigo ). I was getting the error message while trying to run Vertrigo (apache) that port 80 is being used and for my amusement, I never had other servers running to use port 80. However, I wanted to dwell deeper and hence I ran the following command to see which process was using port 80. Start  Command Prompt Hit the combination key of Windows+R (or start run window) Type  cmd  and hit enter. This will open the command prompt Check which process is using port 80 On the command prompt window, type the following command. netstat -o -n -a | findstr 0.0:80 You’ll see an outcome like the one below. The last column is what is called as the  process ID  column. Open  Task Manager  to check the process ID Right click on the taskbar to open the the  task manager . Go to the  Processes  tab. Click the  View  menu And make sure you select the  PID (
    Read more

    Adding a New Protocol IN NS2 (NETWORK SIMULATOR)

    -
    Image
    Adding a New Protocol My Advice to implement new protocol in ns2 is           1)Study the implementation of protocols in ns2                  Eg: If u wanna implement new MAC protocol in the ns2 study the 802.11 MAC implementation in   ns2.           2) Take a Clone of the source protocol(the older one)             3)Modify the clone according to your needs We are taking 802.11 MAC as an example Step 1: Study the implementation of protocols in ns2                                         MAC in ns-2 1. The general structure of MAC related sourcecode:   mac.cc,  mac.h MAC class is derived from Bi-Connector class. Local Variables: pktTx_  pktRx_ Macstate_ : index_  : mac address Basic functions of General MAC class. recv (packet, handler) This is the entry from upper target (a callback handler is given as a parameter) to send a packet to MAC. After the MAC transmit this packet successfully, it will use this callback handler to inform the up
    Read more