N-GEN Communications Web-based Seminars ©NGCS

Seminar - An Overview of Communications Technologies

Module 4 - ATM Technology                                                                                                                      Slide 33 of 46 _________________                                                                                  __________

                                     ATM Network Interfaces                                    

                                User Network Interface (UNI)

                                Network-to-Network Interface (NNI)

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Virtual Channel connections and Virtual Path Connections provide User-to Network Interface (UNI) and Network-to-Network Interface (NNI) transfer with network switching happening at Virtual Channel, Virtual Path and Transmission Path levels.

The Virtual Channels mapped into Virtual Path and the Transmission Path form Virtual Channel Connection. The aggregate bundles of Virtual Channels mapped into Virtual Paths form Virtual Path Connections.

UNI and NNI specifications to interface a Frame Relay network to an ATM network are defined  by Frame Relay Forum and ATM Forum.