N-GEN Communications Web-based Seminars ©NGCS

Seminar - An Overview of Communications Technologies

Module 1 - An Overview of the Communications Industry                                                              Slide 17 of 26 _________________                                                                                  __________

                                             Access Network Protocols

                                            Packet

                                            Frame

                                            ATM

                                            IP

_________________                                                                                  __________

X.25, Frame Relay, ATM and IP are access protocols terminating on the ATM switches to consolidate traffic and then go to the core network ATM switches to go over SONET links. Customers LANS terminate on the core network node using Frame Relay or ATM.

X.25 packet protocol was the dominant end-to-end protocol in the late 1970s to 1980s. Private multiplexer networks also used this protocol in their high speed links.

Frame Relay relegated packet protocol to access protocol in the networks. Frame Relay became the core network protocol. For example the 56 k bps links in the telephone companies' DataPac network were replaced by T-1 speed Frame Relay. 

As ATM protocol standards matured, it replaced Frame Relay in the core networks and Frame was Relay relegated as an access protocol. ATM protocol is also used as an access protocol.

TCP / IP is an end-to-end protocol. TCP / IP traffic is consolidated in the Core network giving traffic efficiency.