Telecommunications Signaling
Highlights the conventions of signalling systems and provides a detailed assessment of their architecture.
TABLE OF CONTENTS Telecommunications Signaling
Chapter 16: Broadband Access Signalling, DSS2
16.1 Introduction
This chapter describes the Digital Subscriber Signalling System No.2 (DSS2), which defines the ITU-T procedures and formats for establishing and clearing broadband connections in the access network.1 DSS2 is the broadband equivalent of DSS1, which is described in Chapter 12. DSS2, in conjunction with the CCSS7 Broadband ISDN User Part (B-ISUP), provides the opportunity for users to invoke broadband services.
DSS2 applies to the control of broadband ISDN (B-ISDN) point-to-point calls on virtual channels. The point-to-multipoint mode of operation that is an option for DSS1 is not used in DSS2 at this stage. The procedures are specified at the interface between B-ISDN terminal equipment and the network. The signalling system is allocated its own virtual channel. The procedures and formats for DSS2 are similar to those for DSS1. This Chapter focuses in the differences applicable to DSS2.
16.2 Capabilities
This Section describes the capabilities provided by DSS2 at present. Further capabilities will be added as part of the evolution strategy for the system.
16.2.1 Connections
The main purpose of the signalling system is to support the setting-up, operation and clearing-down of connections. The connections are of a switched nature, are established in real time and are not automatically re-established in the event of network failure. They operate on a point-to-point basis and represent a collection of ATM Virtual Channel Links that connect two end points (e.g. two user terminals). Such virtual channel connections are explained in Chapters 2 and 14.
The connections are bidirectional, but the bandwidth allocated...
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