B-ISDN architecture and protocol

The authors discuss the architecture and protocol for broadband ISDN (B-ISDN) based on the CCITT standards. The discussion attempts to address the general concept of B-ISDN architecture and protocol and, whenever possible, present alternatives and the rationale for decisions in the selection of the protocol. B-ISDN is presented as a network evolution, and the impact of the asynchronous transfer mode (ATM) on the network is described. The role of virtual channel and virtual path in B-ISDN is discussed. The B-ISDN protocol structure and lower layer functions comprising the physical, ATM, and adaptation layers are presented, and the tentative trends of signaling and traffic control for the B-ISDN are delineated     

Data communications using ATM: architectures, protocols, andresource management

The introduction of ATM is being propelled by the need for fast data communications in public and private networks. What is needed is a clear picture of protocol architectures and traffic characteristics of the various applications to be supported both now and in the future. The authors discuss ATM network architectures with special focus on the support of connectionless LAN interconnection and show which benefits can be obtained from the introduction of a connectionless server in an ATM network. They outline issues related to the use of existing protocols when ATM networks are introduced and show which protocol complexities have to be handled by gateways and servers, again using the example of connectionless LAN interconnection. Having presented network and protocol architectures the issue of data communication in ATM, resource allocation, is treated     

On max-min fair congestion control for multicast ABR service in ATM

In the ATM Forum activities, considerable efforts have focused on the congestion control of point-to-point available bit rate (ABR) service. We present a novel approach that extends existing point-to-point (unicast) congestion control protocols to a point-to-multipoint (multicast) environment. In particular, we establish a unified framework to derive a multicast congestion control protocol for an ABR service from a given rate-based unicast protocol. We generalize a known necessary and sufficient condition on the max-min fairness of unicast rate allocation for a multicast service. Using this condition, we show that the resulting multicast protocol derived using our framework preserves the fairness characteristics of the underlying unicast protocol. The practical significance of our approach is illustrated by extending a standard congestion control mechanism for an ABR service to a multicast environment. The performance of the resulting multicast protocol is examined using benchmark network configurations suggested by the traffic management subworking group at the ATM Forum, and simulation results are presented to substantiate our claims     

ATM WAN performance tools, experiments, and results

Practical experiments in a wide-area ATM network environment are essential to gain a better understanding of the factors affecting ATM performance. This article summarizes the main lessons learned through the authors' practical experiences with ATM and how these can be applied to performance tuning. In order to achieve maximum performance from an ATM WAN, factors ranging from the transport protocol to the equipment used and the network conditions must be carefully taken into consideration. The authors also discuss some of the software-based throughput measurement tools available for the evaluation of high speed network performance, with particular emphasis on NetSpec     

Broadband ISDN ATM layer management: operations, administration,and maintenance considerations

An overview and characteristics of the broadband integrated services digital network (ISDN) that is based on asynchronous transfer mode (ATM) is presented. ATM layer management across the user network interface (UNI) is discussed. The UNI is described, as are the ATM cell structure and its role in management protocols. There are two management protocol models which are explained; however, the focus is on the ATM layer management protocol. An overview of network management functions is provided. Some examples of ATM layer management functions based on the generic functions are provided     

基于ATM的MPLS流量工程研究

研究了基于ATM的MPLS,重点研究和分析了具体实现MPLS流量工程的ATM流控措施、使用约束路由的标记分发协议、路由协议,为MPLS流量工程的具体实施提供了参考。同时研究了MPLS多协议标记交换技术融合IP路由技术、ATM的QoS（Quality of Service）及交换技术,使得流量工程模式可以部署在基于IP的网络,其中包括ATM网上承载IP业务的模式。     

Broadband satellite networks-the global IT bridge

Next-generation broadband satellite networks are being developed to carry bursty Internet and multimedia traffic in addition to the traditional circuit-switched traffic (mainly voice) on a global basis. These satellites provide direct network access for personal applications as well as interconnectivity to the terrestrial remote network segments. The main requirement in success of these networks is that they should be able to transmit high data rate traffic with prescribed quality of service (QoS). Thus, the broadband satellite network has no choice other than the rise of ATM technology and to be optimized for Internet-based traffic. ATM is the promising technology for supporting high-speed data transfer potentially suitable for all varieties of private and public telecommunications networks. IP, on the other hand is the fast-growing Internet layer protocol that is applicable over any data link layer Internet-based applications are the emerging source of traffic in the future wireless networks and broadband satellite networks should consider Internet as the primary service. In this paper, we discuss the traditional ATM and wireless ATM networks and explain the characteristics of the wireless IP networks. The paper then uses those concepts in defining the criteria for the broadband satellite networks such as the QoS and traffic management. Application of the broadband satellite networks is also proposed     

标记分发协议在ATM交换机上的实现

MPLS是一种较好的IP over ATM解决方案，MPLS和ATM技术的结合能够充分发挥在流量管理和QoS方面的作用。标记分发协议是实现MPLS的核心信令协议。本文对在ATM交换机上实现标记分发协议进行了探讨。     

Management and control functions in ATM switching systems

As research has progressed, it has become clear that the main difficulties in ATM pertain to its operational details rather than the concept. And it seems likely that these control issues will be much more complicated and costly for ATM switches when compared with current telephone circuit switches. The asynchronous transfer mode (ATM) is the target switching technique for the future public broadband integrated services digital network (B-ISDN). The purpose of this article is to examine the management and control functions in ATM switching systems implied by current industry standards and agreements on OAM and traffic control. Until now, ATM research in the areas of switch design and traffic control have progressed essentially independently. First, we briefly review the B-ISDN Protocol Reference Model and its representation of the different information flows in ATM. Network management and traffic control principles in ATM, and in particular OAM, are overviewed. With this information as background, we attempt to infer their implications on the functional blocks of an ATM switching system. An example switch architecture model with distributed management and control functions is outlined, and some design issues are discussed     

ATM traffic management in an LMDS wireless access network

We investigate the capacity of LMDS to support ATM services in the local loop. In particular, we evaluate the performance of a MAC protocol for this system when transporting voice and IP traffic using the VBR and GFR service categories of ATM, respectively. Our results show that the MAC protocol is well suited for voice traffic but in general lacks efficient bandwidth management mechanisms to support the more dynamic bandwidth requirements of IP traffic     

A survey of MAC protocols proposed for wireless ATM

Wireless ATM (W-ATM) networks have been studied extensively. The extension of ATM network services to the wireless environment faces many interesting problems. The original ATM network was designed for high-speed noiseless, reliable channels. None of these characteristics are applicable to the wireless channel. One of the most critical aspects of a W-ATM network is the medium access control (MAC) protocol used by mobile terminals (MTs) to request service from the base station (BS), which has to consider the quality of service (QoS) of the specific application. In this article the authors analyze some MAC protocols, particularly those for TDMA systems, and discuss their advantages and disadvantages     

A rough comparison of the IETF and ATM service models

There is much in common between the models of traffic management being devised by the IETF and ATM Forum working groups. The authors' goal is to demonstrate that because of this convergence, there are a number of ways that each can take advantage of the other. The authors discuss service models, link sharing, network provision models, traffic service class hierarchies, borrowing and replacement strategies, delays and throughput, ordering and routing with particular application to the Internet     

Measurement-based simulation model for TCP over ATM

Cell level analysis of ATM networks by means of simulation requires an accurate model for traffic sources. We present a simple model for TCP over ATM traffic sources in an ATM LAN, which captures the fundamental characteristics of the behaviour of tcp in this environment. The model was developed by extensive statistical analysis of numerous traffic traces recorded in an atm testbed. Simulated traffic generated by our model has roughly the same properties as observed in real traffic, even on the time scale of milliseconds. This makes it suitable for use by the analysis of various scheduling and congestion management algorithms.     

Managing ATM-based broadband networks

Some of the asynchronous transfer mode (ATM) virtual path connection (VPC) and virtual channel connection (VCC) performance, fault, and traffic management functions that are currently being addressed in CCITT and T1 standards committees as well as in the ATM forum are presented. The functions include ATM VP/VC connection management, ATM layer operation flows, VP/VC connection performance monitoring, VP/VC connection failure reporting, VP/VC continuity checking, and VP/VC connection operations and maintenance (OAM) cell loopback testing     

The infrastructure for gigabit computer networks

The key features of the synchronous optical network (SONET) and asynchronous transfer mode (ATM) standards for the broadband integrated services digital network (B-ISDN) public network, which is expected to provide a powerful and ubiquitous infrastructure to support the emerging gigabit-per-second data and multimedia applications, are reviewed. The advantages of ATM, the ATM cell format, the B-ISDN protocol reference model and the ATM layer, the ATM adaptation layer, and ATM traffic management and signaling are discussed. An experimental high-performance parallel interface (HIPPI)-ATM-SONET interface is presented as an example to illustrate how the SONET and ATM techniques can be used to provide end-to-end transport for applications requiring a bandwidth of 800 Mb/s and possibly 1600 Mb/s     

Optimization of acyclic bandwidth allocation exploiting thepriority mechanism in the FieldBus data link layer

In process control applications, the bandwidth assigned to acyclic traffic is oversized in order to ensure that the time constraints of control traffic are met. In the FieldBus, a protocol designed to support the exchange of information between sensors/actuators and regulating elements in an automation environment, this means allocating an excessive portion of the macrocycle to acyclic traffic. The use of traffic management based on priority can allow more efficient management of the available bandwidth. The authors analyze the priority mechanism provided for in the FieldBus data link layer and assess various strategies for management of aperiodic traffic and different application scenarios     

Internet QoS路由与业务工程

本文阐述了传统ＩＰ路由协议存在的问题,回顾了ＱｏＳ路由技术在电路交换网络,ＡＴＭ网络和ＩＰ网络中的演进与应用。论述了业务工程在Ｉｎｔｅｒｎｅｔ中的基本功能,以及与之相关的约束路由和ＭＰＬＳ技术。     

APON接人系统协议参考模型及流量管理

在ＡＴＭ标准协议参考模型的基础上,提出了ＡＰＯＮ系统的协议参考模型,对各子层的功能进行了详细的讨论,并对流量的管理进行了研究。     

A hybrid handover protocol for local area wireless ATM networks

While handovers of voice calls in a wide area mobile environment are well understood, handovers of multi-media traffic in a local area mobile environment is still in its early stage of investigation. Unlike the public wireless networks, handovers for multi-media Wireless LANs (WLANs) have special requirements. In this paper, the problems and challenges faced in a multi-media WLAN environment are outlined and a multi-tier wireless cell clustering architecture is introduced. Design issues for multi-media handovers are specified and a fast, continuous and efficient hybrid handover protocol is proposed. The protocol is scalable and supports source and destination mobile handovers in a mutually exclusive manner. Crossover switch (CX) discovery is also introduced to support fast inter-cluster handovers with consideration given to Mobile Quality of Service (M-QoS). The resulting wireless ATM LAN exhibits a distributed mobile location management, call admission control and handover management architecture. A prototype of the proposed handover protocol is implemented into a Cambridge Fairisle ATM switch and the results of handovers for a single Mobile Host (MH) with a single on-going connection are evaluated. It was found that implementing transport mobility for a wireless ATM environment is not practical as the cell re-routing function changes the traffic characteristics and is not scalable to increasing cell rate and to the number of mobile connections. The data-link layer mobility implementation however, is found to work well. The protocol provides symmetric data disruption to traffic flows in both directions and up to seventy-five intra-cluster handovers can be supported in a second. Throughout the experiment, cells arrive in sequence with no cell loss observed during the handover, up to the capacity limit of the ATM switch. Finally, zig-zag handovers and handovers for a single MH with multiple on-going unicast connections are performed in order to evaluate the robustness and performance of the protocol under different MHs' migration and communication environment.Parts of this paper appeared in the ACM First International Conference on Mobile Computing and Networking (MOBICOM'95), Berkeley, California, November 1995 as The Design & Implementation of A Hybrid Handover Protocol For Multi-Media Wireless LANs.C-K Toh is supported by a King's College Cambridge External Research Studentship and a Cambridge Commonwealth Trust Scholarship.     

CMIS/P++: extensions to CMIS/P for increased expressiveness andefficiency in the manipulation of management information

CMIS/P is the OSI systems management service and protocol used as the base technology for the telecommunications management network. It is a generic object oriented protocol that provides multiple object access capabilities to managed object clusters administered by agent applications. Its navigation and object selection capabilities rely on traversing containment relationships. This is restrictive because information models for emerging broadband technologies (SDH/SONET, ATM) exhibit various other relationships. We present extensions to the CMIS service that provide a richer access language and show how these extensions can be supported by corresponding extensions to the CMIP protocol. These extensions allow traversal of any object relationship and filtering out objects at any stage of the selection process. CMIS++ provides much greater expressive power than CMIS, while CMIP++ supports the remote evaluation of the corresponding expressions, minimizing the management traffic required for complex management information retrieval. These extensions follow an incremental approach, starting from a version compatible with the current standard and gradually adding sophisticated features. The applicability and importance of the proposed concepts is demonstrated through an example from SDH management, while we also discuss implementation considerations