Upper-layer Protocols Research Articles

Internet protocols for multimedia communications. I. IPng-the foundation of Internet protocols

Surveys recent and current standardization work by the Internet Engineering Task Force (IETF) on Internet communication protocols. The author describes the IPng project and the IPv6 protocol that will form the basis for upper-layer protocols such as resource reservation, transport and application level protocols. The IETF decided in 1992 to develop a new version of the Internet Protocol (IP) because the available address space of IP version 4 (IPv4) will probably run out early in the 21st Century. The need for a new IP version provided the opportunity to redesign the protocol and add new functions.

End-to-end approach to large-scale multimedia dissemination

We address the problem of realizing large scale dissemination services across a high-speed wide area network. Examples of such dissemination services include media storage services and on-demand multimedia services such as accessing CATV or an on-line video rental store across a network. Unlike the conventional request-response paradigm, such applications involve a single source sending delay-sensitive information to a large number of users scattered across a high-speed wide area network. Communication requirements of such applications are distinct from those based on conventional client-server interactions because the multimedia information demands certain Quality-of-Service (QoS) guarantees in terms of delay constraints and error tolerance. In this paper, we address some of the research issues that must be resolved before we can realize large scale dissemination services across a high-speed WAN. In particular, we argue for an end-to-end approach in which transport and upper-layer protocol cooperate to provide a large scale dissemination service using a best-effort multicast delivery service provided by the underlying network layer. Under an end-to-end approach, a transport protocol takes into account application-level error recovery semantics in its flow and error control strategies to ensure delivery of multimedia information within the QoS constraints of a given distributed multimedia application. We have designed QMTP, a new multicast transport protocol that provides a simplex (unidirectional), rate controlled, quasireliable multicast transport mechanism for large scale dissemination of multimedia information. The paper describes our goals, the research issues that must be solved, our information dissemination model, QMTP flow and error control policies, and results of our performance evaluation.

Service access procedure (SAP) for a transport layer protocol

The article presents the concept and design of a Service Access Procedure (SAP) for establishing transparent and reliable connections between the top three layer protocols of the ISO Open System Interconnection (OSI) and the corresponding bottom four layer protocols. The SAP allows a user to utilize network authentication services and accommodates for a single network login while establishing an active connection. Of the bottom four layers, the transport and network protocols are often selected to be the U. S. Department of Defense (DoD) standard Transmission Control Protocol (TCP) and Internet Protocol (IP), respectively. The upper layer protocols are usually a part of the host processor's software whereas the TCP/IP and the subsequent lower layer protocols might be resident in a physically distinct device such as an interface unit (IU). The rationale for residency of the TCP/IP in IUs, the concept and design of a TCP SAP, and the basis for selection of the lower layer protocols that constitute the host-front-end protocol set are presented in this article.

Upper Layer Protocols and Their Use in MAP

The Manufacturing Automation Protocol (MAP) activity at General Motors (GM) is directed at satisfying the computer communications needs of the factory floor. The MAP specification document is being developed to formalize those needs and identify protocols to be used to meet those needs. The MAP protocol specifications are based on adherence to the International Standards Organization (ISO) seven-layer model for open systems interconnection.