Description: This attribute specifies the bearer capability. It is one of the Broadband Bearer Capability (BBC) attributes. The purpose of the BBC information element is to indicate a requested broadband connection-oriented bearer service to be provided by the network.

The value derivedFromServiceCategory specifies that the actual value which is used for this connection is derived from the value of the atmServiceCategory. Either, this attribute must be set to derivedFromServiceCategory, or the atmServiceCategory attribute must be set to derivedFromBBC, but not both.

Class a service is a connection-oriented, constant bit rate ATM transport service. Class a service has end to end timing requirements and may require stringent cell loss, cell delay and cell delay variation performance.When a is set, the user is requesting more than an ATM only service. The network may look at the AAL to provide interworking based upon its contents.

Class c service is a connection-oriented, variable bit rate ATM transport service. Class c service has no end-to-end timing requirements. When c is set, the user is requesting more than an ATM only service. The network interworking function may look at the AAL and provide service based on it.

Class x service is a connection-oriented ATM transport service where the AAL, trafficType (vbr or cbr) and timing requirements are user defined (that is, transparent to the network).When x is set the user is requesting an ATM only service from the network. In this case, the network shall not process any higher layer protocol.