- Shopping Bag ( 0 items )
This hands-on book focuses on the practical aspects of ATM signalling that network engineers and designers will need to know now and in the foreseeable future. It covers the basic call control functions as well as Internet Protocol over ATM, LAN emulation, multiprotocol over ATM, and much more. Case studies are also included to demonstrate this technology in action.
Asynchronous transfer mode (ATM) is the most sophisticated telecommunications technique available for simultaneous transmission of sound, data, and images across broadband integrated services digital networks (B-ISDN). Signalling in ATM networks includes standards governed by different standardization bodies.
In aTM networks the information is transmitted between communicating entities using fired-size packets, referred to as the aTM cells. an aTM cell has a length of 53 octets, consisting of a 5-octet header and a 48-octet payload field. Therefore, all data transmitted from a source must be se-mented into cells of this size. Then these cells can be transported as a stream by the aTM network. If different streams need to he transported, the associated cells can be multiplexed inside the aTM network. This process increases the network utilisation and is essential to achieve an economically working network. Connection-oriented networks like aTM substantially differ from con connections networks like Internet Protocol lip) in the need for control protocols. In connectionless networks all information that is needed to act the information from the source to the destination is contained in every datagram. In connection-oriented networks a connection must be established before data can be transmitted. This is done by means of control protocols. Naturally. in connection-oriented networks it is easier to support quality of' servicemuch more information can he exchanged in the connection establishment phase between the network and the user (in pure Con connectionless networksone would need to carry this information in every datagram) and network resources can be verified and reserved in the establishment phase. The network can optimise the route and lit it to the needs of the user.
The philosophy and architecture of the aTM control plane stems from the telephone network. Many of the concepts and much of the terminology are adapted to a broadband em ironment (in aTM speak narrowhand means the telephone network. broadband means asynchronous Transfer Mode (aTM)). In contrast to IP. aTM was first standardised and then implementation begun. all this together has led to a quite complicated architecture.
The aTM protocol architecture is usually described as a cube consisting of planes (Figure I . I ). aTM networks distinguish between the data, control and management planes. The data plane defines the protocol layers that are used to process user data, whereas the control plane defines the stack of protocols that are used to establish. tear-down and modify user and control connections. The management planes are used to manage the layers of the user and control plane (layer management) and the planes as a whole (plane management). In this book .ve focus on the control plane protocols used in private aTM networks. We expect the reader to he familiar with the general concepts of aTM: cells, virtual channels 1.1 Organisation of the Book This hook describes the most impoi-talit protocols of the aTM control plane that are used in private aTM network. In Chapter 3 we start with the User-Network Interface (UNI) protocol, w hick is the central protocol to establish connections in an aTM network. Chapter 5 analyses the layer below the UNI-the Signalling aTM adaptation Layer (SaaL). This lave provides transport ,,ci-% ices to the UNI. aTM is asymmetric in the sense that the protocols at the boundary of tile network (the UNI) are different ti-ont the protocols inside the network. Chapter 6 concentrates on tile routing and connection control protocols inside the network Private Network Node Interlace (PNNI). UNI links need to he managed. This is the task of the Integrated Local Management Interface (ILMI) which is discussed in detail in Chapter 7. a couple 1 protocols use the services of the aTM control protocol a» to to provide other network services. The most popular of these protocols. Classical IP over a'I'M (CLIP) and I-aN Emulation over aTM (LaNE.), are described in Chapter S. Two appendices help the reader to find the way through the labyrinth of ITU-T standards (appendix a) and to find source code for tracing `l tools and protocol software as well as to find standard documents (appendix I3).
1.2 Systems used for Experiments
In this book we show the results of several experiments with aTM systems. The experiments were performed in the aTM laboratory of GMD Fokus. In our experiments we used up to lour different aTM switches. The names of these switches are foreplay, forelle...
Overview of ATM Signalling.
UNI: User-Network Interface.
SAAL: Signalling ATM Adaptation Layer.
PNNI: Private Network Node Interface.
ILMI: Integrated Local Management Interface.
Protocols on Top of ATM Signalling.
Appendix A: ITU-T Standards.
Appendix B: Source Code Availability.