�1���� Introduction
�2���� Circuit witched data transmission
service
�3���� Packet switched data transmission
services
������� 3.1���� Direct access to a packet switched
data transmission service
������� 3.2���� Port access to a packet switched
data transmission service (user classes of service 20-26 and 29)
������� 3.3���� Port� access to a packet switched data transmission service (user
classes of service 8-12, 26 and 30)
������� 3.4���� Additional capabilities provided
by multicast service
�4��
��Frame
relay data transmission service
������� 4.1���� Direct access to a frame relay
data transmission service
������� 4.2���� Port access to a frame relay data
transmission service
�5���� Leased circuit data transmission
service
Appendix I � Coding of optional user
facilities
������ II.1���� Introduction
������ II.2���� Independent operation
������ II.3���� Minimum relationship
������ II.4���� Maximum relationship
������ II.5���� Summary