Connection Admission Control (CAC)

In terms of communication, the existence of CAC is common, especially in network-oriented connections (CAC does not provide any service to connectionless networks). In addition, in connection-oriented networks, CAC plays an important role, particularly for congestion control.

The basic role of connection admission control in connection-oriented networks is to decide whether there are enough free system resources available before establishing a new connection. An end-to-end connection is only established when the availability of free resources is assured.

CAC performs the following two operations while establishing a connection:

1. It establishes a connection when resources are free and available.
2. If the connection is rejected in the absence of free/available resources, a notification is sent back to the originator or requester of the call or connection.

The following factors are to be considered when establishing or requesting a connection:

• The type of service required
• Traffic parameters (source traffic parameters are analyzed)
• Both directions request their required QoS, which is also considered when establishing a connection.