IBM ATM OC-3c manual ATM is Service Transparent, ATM is Connection-oriented

ATM is Service Transparent

ATM allows for the high speed transfer of a wide range of user traffic, including voice, video and other data.

The cell format means that more than one service (traffic type) can be multiplexed over the same physical line, see Figure 2-4.

Figure 2-4Service Processing

Cells are de-multiplexedat the other end of the connection and forwarded to the correct service destination.

Multi-service processing promotes scalability by significantly reducing the number of changes needed to add new service traffic types to your network.

Asynchronous Transfer Mode (ATM) Layer 2-9

ATM is Connection-oriented

ATM is a connection-orientedtransport service that requires a communication channel to be set up between the ATM source and destination end-systems before ATM cells can pass between them.

Before a direct data connection can be set up between two end-systems, a number of control connections are set up. These control connections are beyond the scope of this guide. If you require further information about control connections, refer to the ATM Forum’s “LAN Emulation Over ATM” document.

Figure 2-5 shows the logical structure of a communication channel.

Figure 2-5Communication Channels

Several communication channels can operate over the same physical link. Each Virtual Path Connection (VPC) contains several communication channels known as Virtual Channel Connections (VCCs).

The ATM Module only manages Virtual Channel Connections (VCC).