N-GEN Communications Web-based Seminars ©NGCS

Seminar - An Overview of Communications Technologies

Module 4 - ATM Technology                                                                                                                      Slide 21 of 46 _________________                                                                                  __________

                    ATM Services, ATM Layer and Adaptation Layers
                                       (ATM Protocol Reference Model)

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The ATM protocol stack for discussion in our seminar consists of:

1.    A physical layer - SONET or Cell-based
2.    An ATM layer - where the cells are built
3.    An ATM Adaptation layer - interfaces upper layer protocols with the ATM layer i.e. grooms the
       information put into ATM cells. It is equivalent to the layer 2 (data link) of the OSI model. 

The other layers and functions of the ATM Model are beyond the scope of this seminar. The following slides will discuss the ATM Adaptation layers in detail.