Functions of header subfields

Q.  Which of the following is/are functions of header subfields?

I. Router change flag
II. Virtual path identifier
III. Header error control
IV. Cell loss priority

- Published on 19 Oct 15

a. III, IV
b. II, III, IV
c. I, II
d. I, III, II



  • Prajakta Pandit   -Posted on 07 Oct 15
    - For transferring data from one machine to another, we can use different methods in networking.
    - ATM (Asynchronous Transfer mode) is a part of networking that can be used for transferring the data.
    - ATM is a packet oriented transfer technique, which is based on the use of fixed length cell.
    - This cell is classified into two sections,
    1. Header
    2. Payload
    - Header consists of 5 bytes that identify the cells belonging to the same virtual channel.

    - The following functions are performed by header subfields,-

    1. Virtual path identifier
    2. Header error control
    3. Cell loss priority

    1. Virtual path identifier
    - It creates a path for the network routing.

    2. Header error control
    - It provides CRC (Cyclic Redundancy Check) calculation over the header field for error detection and correction which helps to reduce the cell loss problem and mis-routing due to transmission errors.

    3. Cell loss priority
    - It identifies the lower priority cells which can be discarded on the basis of network condition.

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