Cell Utilization Efficiency of Internet Protocol Traffic over Asynchronous Transfer Mode Networks

In the near future, large computer networks will be connection oriented, with at least the data link connectivity being provided by the Asynchronous Transfer Mode. (ATM) networks. However, these networks may have to communicate with the existing network which predominantly use Internet Protocol (IP). Running Internet Protocol over Asynchronous Transfer Mode Network has been a contentious issue due to the inefficient segmentation of Internet Protocol packets into Asynchronous Transfer Mode (ATM) cells. In this thesis, the current protocols and standards pertaining to Internet Protocol over Asynchronous Transfer Mode are discussed and overheads involved in placing Internet Protocol packets into Asynchronous Transfer Mode cells, taking Logical Link Control/Sub Network Attachment Point Encapsulation into consideration, are analysed to find out the cell utilization of Asynchronous Transfer Mode cell in carrying the Internet Protocol packets. The Wide Area Network (WAN) oriented traffic for our analysis is collected from the Internet Traffic Archive. Analysis of the trace results show that the Asynchronous Transfer Mode cell utilisation is better in carrying the user information if the Internet Protocol packet are sizes larger. It is observed that ranges of Internet Protocol packets require similar number of Asynchronous Transfer Mode cells. At small values of Internet Protocol packets, the efficiency of Asynchronous Transfer Mode cell in carrying the user information is significantly low due to the Logical Link Control Encapsulation, padding and the trailer overheads. The Asynchronous Transfer Mode Cell utilization is better in Virtual Circuit (VC) based multiplexing, saving 8 bytes of encapsulation for each packet, thus improving the Asynchronous Transfer Mode (ATM) cell utilization marginally. It is seen that 80% of the Internet Protocol packet length varies from 54 to 200 bytes for which cell utilisation varies from 50%-to 82%. However, the average cell utilisation is 84% in the 20,000 packets observed since 20% of the Internet Protocol packet length is greater than 1000 bytes

Connectionless communications using the Asynchronous Transfer Mode

For a large number of applications, there is a strong need for the provision of a connectionless service by the B-ISDN. However, the cell-based ATM, which is used for switching and multiplexing in this public telecommunication network, is a connection-oriented technique. The B-ISDN should therefore be extended with functionality to allow for connectionless communications. This dissertation addresses the design and analysis of such an extension. An architectural framework is presented, which places the protocols to be used in perspective. Two possible network architectures result from the functional decomposition of the connectionless service into cooperating protocol entities \ud and the underlying ATM service. In the first one, end-systems of the B-ISDN are interconnected by means of end-to-end ATM connections. In the second one, endsystems are connected to special entities in the B-ISDN, called Connectionless Servers (CLSs). The CLSs are interconnected by ATM connections, thus constituting a connectionless overlay network on top of ATM.\ud A number of different implementation architectures for a CLS are proposed, and analysed with respect to effectiveness, availability, scalability, and in particular, performance. The major distinction between these implementation architectures is the distribution of functionality over modules. Furthermore, two different modes of operation are identified for a CLS. In the message mode of operation, a packet is reassembled from the incoming cells before it is processed and forwarded. In streaming mode of operation, the first cell of a packet is immediately processed and forwarded upon arrival, while state information is maintained for the processing and forwarding of subsequent cells of the packet. A number of performance models are developed in this dissertation. An approximate model of a CLS is analysed to allow for comparison of the delay which is experienced by cells for different implementation architectures and modes of operation. If the bandwidth assigned to ATM connections between CLSs is relatively high, message mode of operation yields the lowest delay, otherwise streaming mode performs best. In order to support the dimensioning of a reassembly buffer in a CLS operating in message mode, another, more detailed model is developed and analysed. It allows the computation of the packet loss probability of a buffer, as a function of its size. An essential function for the provision of a connectionless service using ATM is connection management. This function instructs the signalling system of the B-ISDN to establish and release ATM connections as needed for the transfer of packets. A new mechanism is proposed that exploits the expected correlation\ud between subsequent packet arrivals to reduce the average bandwidth that needs to be reserved by the ATM network. A performance model is developed and analysed to determine the optimal control parameters of the new mechanism, and to evaluate its behaviour. It is shown that bandwidth reductions of up to 95% can be obtained, compared to conventional mechanisms, without affecting the \ud average delay experienced by packets

Future of asynchronous transfer mode networking

The growth of Asynchronous Transfer Mode (ATM) was considered to be the ideal carrier of the high bandwidth applications like video on demand and multimedia e-learning. ATM emerged commercially in the beginning of the 1990\u27s. It was designed to provide a different quality of service at a speed up 100 Gbps for both real time and non real time application. The turn of the 90\u27s saw a variety of technologies being developed. This project analyzes these technologies, compares them to the Asynchronous Transfer Mode and assesses the future of ATM

Source Behavior for ATM ABR Traffic Management: An Explanation

The Available Bit Rate (ABR) service has been developed to support data applications over Asynchronous Transfer Mode (ATM) networks. The network continuously monitors its traffic and provides feedback to the source end systems. This paper explains the rules that the sources have to follow to achieve a fair and efficient allocation of network resources.Comment: IEEE Communications Magazine, November 1, 1996, vol 34, no11, pp50-5

Performance and Buffering Requirements of Internet Protocols over ATM ABR and UBR Services

The Asynchronous Transfer Mode (ATM) networks are quickly being adopted as backbones over various parts of the Internet. This paper analyzes the performance of TCP/IP protocols over ATM network's Available Bit Rate (ABR) and Unspecified Bit Rate (UBR) services. It is shown that ABR pushes congestion to the edges of the ATM network while UBR leaves it inside the ATM portion.Comment: IEEE Communications Magazine, Vol 36, no 6, pp152-15

Asynchronous Transfer Mode Quality-of-Service Testing

In support of satellite-ATM interoperability, researchers at the NASA Lewis Research Center performed asynchronous transfer mode (ATM) quality-of-service experiments using MPEG-2 (ATM application layer 5, AAL5) over ATM over an emulated satellite link. The purpose of these experiments was to determine the free-space link quality necessary to use the ATM protocol to transmit high-quality multimedia information. The experimental results have been submitted to various International Telecommunications Union (ITU) study groups in order to improve and modify current standards and recommendations for the telecommunications industry. Quality-of-service parameters for Class I, stringent class requirements for ITU-T I.356 are currently being debated. The experimental results presented will help to establish these quality-of-service thresholds. This material will also be useful in the development of the ITU-R WP-4B's Draft Preliminary New Recommendation on the Transmission of Asynchronous Transfer Mode Traffic via Satellite (Rec. S.atm)

Saturation routing for asynchronous transfer mode (ATM) networks

The main objective of this thesis is to show that saturation routing, often in the past considered inefficient, can in fact be a viable approach to use in many important applications and services over an Asynchronous Transfer Mode (ATM) network. For other applications and services, a hybrid approach (one that partially uses saturation routing) is presented. First, the minimum effects of saturation routing are demonstrated by showing that the ratio, defined as f, of routing overhead cells over information cells is small even for large networks. Second, modeling and simulation and M/D/l queuing analysis techniques are used to show that the overall effect on performance when using saturation routing is not significant over ATM networks. Then saturation routing ATM implementation is also provided, with important extensions to services such as multicast routing. After an analytical comparison, in terms of routing overhead, is made between Saturation Routing and the currently proposed Private Network-Network Interface (PNNI) procedure for ATM routing made by the ATM forum. This comparison is made for networks of different sizes (343node and 2401 -node networks) and different number of hierarchical levels (3 and 4 levels of hierarchy). The results show that the higher the number of levels of hierarchy and the farthest (in terms of hierarchical levels) the source and the destination nodes are from each other, the more advantageous saturation routing becomes. Finally, a set of measures of performance for use by saturation routing (or any routing algorithm), as metrics for routing path selection, is proposed. Among these measures, an innovative new measure of performance derived for measuring quality of service provided to Constant Bit Rate (CBR) users (e.g., such as voice and video users) called the Burst Voice Arrival Lag (BVAL) is described and derived

Survey of congestion control techniques for an ATM network

The emerging broadband integrated services digital network is expected to adopt ATM (Asynchronous Transfer Mode) as the transport network. This new network must support several classes of service with varying delay and loss requirements. It must also operate with link speeds in the hundreds of megabits per second and be scalable up to potential link speeds on the order of gigabits per second. The requirements to support multiple services and high speed make the congestion control in an ATM network difficult. This paper reviews sorne of the techniques for prevention and control of congestion in an ATM network

Satellite B-ISDN traffic analysis

The impact of asynchronous transfer mode (ATM) traffic on the advanced satellite broadband integrated services digital network (B-ISDN) with onboard processing is reported. Simulation models were built to analyze the cell transfer performance through the statistical multiplexer at the earth station and the fast packet switch at the satellite. The effectiveness of ground ATM cell preprocessing was established, as well as the performance of several schemes for improving the down-link beam utilization when the space segment employs a fast packet switch