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Unit 13: Session Layer and Presentation Layer




          13.6 Keywords                                                                         Notes

          Abstract Syntax Notation (ASN.1) is an OSI standard dealing with the issue of representing,
          encoding, transmitting, and decoding data structures.

          Activity management enables the user to delimit data into logical units called activities.
          Authentication verifies the antecedents of the remote party being the real party rather than an
          impostor.

          Dialog management works towards to decide whose turn it is to talk.
          Huffman encoding is used to encode symbols according to the frequency of their use.
          Major synchronization points divide a message into a series of dialogs.

          Minor synchronization points are just markers and inserted into the middle of dialogs.
          Run Length Encoding is an alternative to encode data containing repetitive symbols.
          Synchronization provides synchronization points for data transfer.
          Translation converts the complex data structures used by an application strings, integers,
          structures, etc. into a byte stream that may be transmitted across the network.

          13.7 Review Questions

          1.   Explain briefly the functions of the presentation layer.
          2.   What is the difference between minor synchronization points and the major
               synchronization points?
          3.   What are the elements of the presentation layer?
          4.   Explain the process of synchronization with respect to session layer.
          5.   Differentiate between session layer and presentation layer.

          Answers: Self Assessment


          1.   session                          2.   presentation
          3.   session                           4.  activities
          5.    two                              6.  Sequence
          7.   Presentation                     8.   Session

          9.   Transport, session                10.  Synchronization
          11.  Encryption

          13.8 Further Readings




           Books      Andrew S. Tanenbaum, Computer Networks, Prentice Hall.
                      Behrouz A. Forouzan and Sophia Chung Fegan, Data Communications and
                      Networking, McGraw-Hill Companies.





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