Integrated services digital networks

The purpose of this thesis is to study three types of
bandwidth allocation strategies for a network integrating
voice and data, commonly referred to as Integrated Services
Digital Network or ISDN, using GPSS V simulati ons. The
strategies are Non-Boundary, Movable-Boundary, and Non- and
Movable- Boundary with Digital Speech Interpolation. The
theoretical behavior of each strategy is discussed. Exact
solutions for small systems with one or two slots is shown
along with approximations for larger systems. General
descriptions of the GPSS models for each strategy is
provided. The GPSS model source code for each strategy is
presented in the Appendix. Simulation is used to explore
the effects of the service time ratio a of voice and data on
system performance. Also, the performance of Time Division
Multiplex or TDM systems with 24 channels, commonly referred
to as Tl, is shown.

The last decade has seen a surge in demand for cellular and WLAN networks. With the introduction of Voice Over IP, cellular companies are looking at WLAN-Cellular integrated networks that shall provide users with economical voice and data services. These networks shall be complimentary to the existing cellular networks. A lot of money is spent in registering and authenticating new users, since they are separately authenticated and registered on the WLAN and Cellular domains. This leads to extra costs for the company. Thus for the integrated networks to have an impact on the market some issues such as simpler authentication and registration must be resolved. Therefore we propose a new inter-working model that shall addresses the authentication and registration problem for an integrated network for voice and data. The Single authentication system of the new inter-working model, shall authenticate the user in an integrated network using the SIM credentials, this authentication shall be valid for both voice and data. Also registration costs will be saved by preventing separate registration of users in the WLAN and Cellular domain.

This thesis addresses a method to deduce the statistical bounds associated with the cell-transfer delay variations (CDVs) encountered by the cells of MPEG traffic, transmitted in the Asynchronous Transfer Mode (ATM) networks. This study focuses on: (1) Estimating CDV arising from multiplexing/switching for both constant bit rate (CBR) and variable bit rate (VBR) traffics via priority allocation based simulations. (2) Developing an information-theoretics based technique to get an insight of the combined BER-induced and multiplexing/switching-induced CDVs in ATM networks. Algorithms pertinent to CDV statistics are derived and the lower and upper bounds of the statistics are obtained via simulations in respect of CBR and VBR traffics. Ascertaining these bounds is useful in the cell admission control (CAC) strategies adopted in ATM transmissions. Inferential remarks indicating the effects of traffic parameters (such as bandwidth, burstiness etc.) on the values of the statistical bounds are presented, and scope for further work are presented.

In order to effectively transport digital compressed video over Broadband Integrated Services Digital Networks (B-ISDN) with Asynchronous Transfer Mode (ATM), the characteristics of the video source traffic should be understood. The nature of the video traffic depends primarily on the source, the content of the video and the coding algorithm that removes redundancies for efficient transmission over networks. In this study, video conference data encoded using a subband coding scheme, Digital Video Compression System (DVCS), is analyzed to determine its characteristics. Several video traffic sources are multiplexed through an ATM network node with limited capacity and the performance of this environment is evaluated by using a simulation technique. The simulation results are presented for the performance measures for varying traffic and network conditions.

Broadband-ISDN Network Architecture and Signaling concepts are described with particular emphasis on Asynchronous Transfer Mode (ATM) technology. A consolidated view of various aspects of B-ISDN/ATM Access and Network Signaling functions, architecture and protocols is presented. Additionally, a suggested evolutionary growth path for the B-ISDN signaling protocols is summarized. This is followed by a high-level comparison of two protocols under consideration for network signaling. The result of this evaluation indicates that the requirements of network signaling are best met by a protocol stack based on SS7 concepts. Finally, a set of future B-ISDN and Multimedia services is presented in context of the requirements they would impose on the signaling protocols. Enhancements to the access signaling protocol are proposed for the support of multiconnection and/or multiparty calls. These extensions/enhancements consist of a set of simplified messages, information elements and procedures based on message flows. Evolution and backward compatibility to existing protocols are taken into account while developing the extensions.

This thesis illustrates the design of non-proprietary and practical ISDN terminal equipment for basic access. Terminal compatibility with the AT&T 5ESS, Northern Telecom DMS100, and Siemens EWSD Class 5 switches is considered. General compliance is dictated by all applicable CCITT recommendations and BELLCORE technical references. A consolidation of the useful information in the CCITT and BELLCORE technical documents is provided from a design engineer's perspective. A practical, cost effective implementation is outlined and considerations for flexibility due to the changing requirements are explored. The objective is to specify simplified guidelines which can be followed to create generic ISDN terminal equipment which is non-proprietary and practical for ISDN subscribers today.

Rapid advances in technology have resulted in the evolution of Integrated Services Digital
Networks (ISDNs) to Broadband ISDNs (BISDNs). This thesis discusses and evaluates the
performance of a high speed and high capacity packet switching system architecture for
BISDNs. This system supports various high speed communication services like data, voice,
and video services. The main performance criterion is the mean switching delay, which
is defined as the packet transfer delay through the bus and through the loop connecting
various switch modules in the system. Other performance criteria are power and system
throughput. The performance parameters are evaluated separately for both data and control
(signaling) packets. The effects of the number of switch modules in the system, the data
packet length, and the ratio of arrival rate of data to control packets are examined.
It is observed that the switching delay and throughput increase with an increase in the
traffic intensity for any number of switching modules and the ratio of arrival rate of data
to control packets. The delay for data packets is found to be higher for lower values of
this ratio and vice versa. The power is found to be maximum for about 70% load. The
switching delay in this simulation model is found to be less than one millisecond for data
packets.

This thesis deals with the major concepts, evolution, and the implementation of common channel signaling systems in current telecommunications networks. An analytical model for performance evaluation of networks design, using Signaling System #7, is presented. The primary emphasis is to calculate the average delay of messages based upon error probability and data transmission rate. The thesis describes existing common channel signaling systems. CCITT Signaling System #6 and #7 are explained. United States versions of signaling systems, CCIS #6 and CCS #7 are examined in detail. The move toward Integrated Services Digital Networks (ISDNs) is discussed in terms of interfaces, and standards. CCS architectures in support of ISDNs are outlined.

This thesis deals with the major issues concerning a smooth transition into the Integrated Services Digital Network (ISDN). The goals of technology improvements, cost/performance effectiveness, user acceptance of ISDN services, converting the network to an all digital network, and standardization are essential for the economic acceptance by the ISDN user. The uses of ISDN are not completely known, it is therefore very difficult to accurately plan the ISDN network. Because of this uncertainty, the call holding time is difficult to determine. This thesis shows the effects on the D channel occupancy by varying both the call holding time along with varying the packet data over the signaling channel. It is shown that a low call holding time drastically increases the traffic load over the D channel.

This thesis evaluates the performance of the D-channel which is part of the Basic Rate interface in an Integrated Services Digital Network (ISDN). A channel is a specified portion of the information-carrying capacity of the interface. The Basic Rate interface supports three channels; two B-channels and one D-channel. As ISDN user, physically connected on a passive bus, contends and resolves access for the D-channel, or signalling channel. In this thesis the D-channel and the contention resolution are modeled and simulated as a queueing system. Simulation results using the non-preemptive priority queueing discipline with deterministic and truncated exponential service times are presented. Performance is measured in terms of delay and queue length characteristics.