Examination of the applicability of router and bridging techniques

Bridges are compared to routers from a number of perspectives. Routers are systems that interconnect networks based on information contained in layer 3, the networking layer, of the Open Systems Interconnection (OSI) model. Bridges use layer 2 (data link layer) information to determine whether packets should be passed from one network to another. This type of interconnection strategy use node address data only and thus is independent of the protocol used for OSI layer 3 and above. Processing requirements of bridges and routers are compared, highlighting the more complex processing needs of the latter. The greater functionality and flexibility of routing, which accompanies this increased complexity, is discussed. In particular, the focus is on the ability of routers to interconnect different local area network techniques, deal with heavy traffic, and control topology     

A multiprocessor approach for meeting the processing requirementsfor OSI

To meet the increased communication processing requirements of high-speed networks, a multiprocessing network interface is considered for processing multiple layers of a communication protocol stack. In particular, the processing of the open systems interconnection (OSI) layers 2 to 6 on the network interface are considered. OSI processing is computationally expensive because of the inclusion of the transfer syntax conversion at the presentation layer. The approach taken is to process different packets in parallel. The results obtained from simulations indicate that the approach has promise for OSI processing at higher rates     

Connections and connectionless data transmission

The complementary concepts of connection-mode data transfer and connectionless data transmission are the fundamental models of communication in the architecture of Open Systems Interconnection (OSI). As the names imply, connection-mode data transfer involves the establishment and maintenance of a connection, which represents a dynamically negotiated agreement concerning the transfer of a series of related units of data; connectionless data transmission relies only on the prior knowledge that peer entities have of each other to transmit independent, unrelated data units, and does not involve the establishment of a connection. The two concepts together describe all of the peer-to-peer interactions that take place in the OSI environment. The national and international organizations concerned with OSI have applied these concepts successfully in the development of OSI service and protocol standards.     

Transmitting time‐critical data over heterogeneous subnetworks using standardized protocols

Current communication networks consist of subnetworks of different types. Therefore a common network protocol has to be used for the transmission of data in such a heterogeneous network. Since some time the requirement of mobility in communication networks is showing up. For that reason wireless networks are playing an increasing role as subnetworks. On the other hand there is the need for multiplexed transmission of time-critical and non time-critical (normal) data within a heterogeneous network. In this paper we discuss the problem of multiplexed transmission of time-critical and of non time-critical data over a wireless type subnetwork using a common standardized network protocol. Many of the available wireless subnetworks are of low or medium transmission speed and guarantee a fixed transmission bandwidth at the access point. We describe a mechanism to transmit time-critical data in such a type of subnetwork using a connectionless transport and a connectionless network protocol. The concurrent transmission of non time-critical data using a connection oriented transport and the same connectionless network protocol is assumed to be of lower priority; it is scheduled in a way to fill the remaining capacity, which has not been reserved for the transmission of time-critical data. In our discussion we concentrate on the standardized ISO/OSI protocools CLNP as connectionless network protocol, CLTP as connectionless transport protocol and TP4 as connection oriented transport protocol. We propose a header compression protocol and a fragmentation protocol for use on low bandwidth subnetworks. This revised version was published online in June 2006 with corrections to the Cover Date.     

Omissions and ambiguities in CCITT Recommendation Q.921

The data link layer protocol for the integrated services digital network (ISDN) user/network interface, known as link access protocol-D (LAPD), is a protocol that operates at layer 2 of the open systems interconnection (OSI) architecture. Its purpose is to safely convey information between layer 3 entities using the D-channel. The information types that LAPD is intended to transport include call control signaling, packet mode communications, and management information. Observations are made in this article about what are, in the authors' opinion, the most confusing points of CCITT Recommendation Q.921 with comments related to data link layer address field, broadcast connections, terminal endpoint identifier (TEI) management procedures, layer 2 frames exchange, and connection management entity response to MDL-error indication primitives. This article intends solely to clarify the recommendations so that their concepts and procedures become easier to understand and implement, which can lead to significant saving of time for those who must eventually use LAPD procedures or develop the software for handling them     

A Cross-Layer Architecture of Wireless Sensor Networks for Target Tracking

We propose the Low Energy Self-Organizing Protocol (LESOP) for target tracking in dense wireless sensor networks. A cross-layer design perspective is adopted in LESOP for high protocol efficiency, where direct interactions between the Application layer and the Medium Access Control (MAC) layer are exploited. Unlike the classical Open Systems Interconnect (OSI) paradigm of communication networks, the Transport and Network layers are excluded in LESOP to simplify the protocol stack. A lightweight yet efficient target localization algorithm is proposed and implemented, and a Quality of Service (QoS) knob is found to control the tradeoff between the tracking error and the network energy consumption. Furthermore, LESOP serves as the first example in demonstrating the migration from the OSI paradigm to the Embedded Wireless Interconnect (EWI) architecture platform, a two-layer efficient architecture proposed here for wireless sensor networks     

A comparison between the OSI reference model and the B-ISDNprotocol reference model

The author presents views on the relationships between the Open Systems Interconnection (OSI) reference model (RM) and the broadband integrated services digital network (B-ISDN) protocol reference model (PRM), in an attempt to facilitate an interconnection between B-ISDN and data networks conforming to the OSI standards. According to the International Telecommunications Union-Telecommunications Sector (ITU-T), the exact relationship between the lower layers of the OSI RM and the B-ISDN PRM is for further study     

An Optical Layer Lightpath Management Protocol for WDM AONs

In this work, we propose a control protocol for lightpath management in the optical layer of all-optical networks (AONs). AONs follow a layered structure, as used by various network standards, where each layer communicates with its peer through Protocol Data Units (PDUs). In the context of Open System Interconnection (OSI) Reference Model (RM), a new layer, called optical layer, has been introduced in the AON architecture to manage the lightpath related functions. The optical layer lies in between the physical layer and the data link layer. The objective of this paper is to define a specification for an optical layer protocol for managing lightpaths in AONs. In order to study the dynamics of the optical layer protocol system, we first employ the communicating finite state machine model to represent the protocol. Then a reachability analysis of the model is performed to verify the protocol. This paper shows how the optical layer protocol can be specified formally and made error-free by the step-wise refinement of an initial specification, where validation is done after each refinement.     

A prototype SECS message service for communication in thesemiconductor manufacturing environment

The authors describe the SECS message service (SMS), a bidirectional protocol that can be used to transfer SECS formatted messages over an ISO-compatible network. SECS is the current protocol standard for communications in the semiconductor manufacturing manufacturing environment. SMS represents a first effort that provides for the migration of communication methodologies in the semiconductor manufacturing environment into the ISO arena. SMS incorporates desirable features of the SECS protocol into an OSI application layer environment, thus achieving advantages of both environments. The SMS protocol provides four services to the end user: MESSAGE provides for the transfer of SECS formatted messages, CONNECT provides for the establishment of virtual circuit connections between applications in a SMS ISO environment, DISCONNECT provides for the graceful ending of such operations in which no data are lost, and ABORT provides for the abrupt termination of such connections in which data may be lost. The SMS design process has produced the additional result of a methodology for incorporation of desirable features of a non-ISO protocol into an ISO-compatible system     

Cross-layer design of ad hoc networks for real-time video streaming

Cross-layer design breaks away from traditional network design where each layer of the protocol stack operates independently. We explore the potential synergies of exchanging information between different layers to support real-time video streaming. In this new approach information is exchanged between different layers of the protocol stack, and end-to-end performance is optimized by adapting to this information at each protocol layer. We discuss key parameters used in the cross-layer information exchange along with the associated cross-layer adaptation. Substantial performance gains through this cross-layer design are demonstrated for video streaming.     

The OSI file service

The OSI File Service defines a standard for transferring, accessing, and managing information stored in or moved between open systems as files. Within the framework defined by the OSI Reference Model the OSI File Service resides within the Application Layer (OSI layer 7). The OSI File Service describes features for basic file transfer and access allowing manipulation of the data contained in a file and features for management of individual files. To minimize the amount of detailed technical information that one needs to determine about a system before communicating with it, the OSI File Service establishes a common model for files. The model used by the OSI File Service is called the Virtual Filestore. Describing file transfer, access, and management in terms of the Virtual Filestore allows interconnection of a wide range of systems of different complexity. The definition of a number of optional subsets within the Virtual. Filestore allows simpler systems to interwork with more sophisticated ones. The OSI File Service defines the aims and objectives that the protocol must achieve. The application protocols for the OSI File Service support the activities required for file transfer, access, and management between open systems.     

Relationship of the Signaling System No.7 protocol architecture tothe OSI reference model

The relationships that currently exist between the Signaling System No.7 (SS7) and Open Systems Interconnection (OSI) architectures are examined. The functions of each layer in the SS7 protocol stack, as well as the SS7 addressing mechanisms, are described to the extent necessary to show correspondences to those of OSI. Those areas where the two architectures do not align are highlighted. The criteria by which alignment of SS7 with OSI standards is judged are explained. Work in progress in CCITT in defining the evolution of various SS7 application layer standards, where a conscious effort is being made to attempt to align with OSI standards, is described     

EuroBridge: communications services for multimedia applications

The aim of the EuroBridge project is to provide a uniform communication service platform. This platform will provide true multimedia multipoint services including interactive video conferencing and store-and-forward data services. The project will enhance selected OSI application layer services to provide them with multimedia capabilities. Selection of the initial services as well as the identification of necessary functional enhancements were based on actual user requirements. To support the dedicated communication requirements imposed by multimedia and multipoint applications, the lower layers of the OSI model will be enhanced accordingly. This includes designing and implementing new lightweight session and presentation protocols, respectively. Furthermore, high-speed transport protocols will be utilised. The actual protocol stack used will be configured dynamically depending on the requested quality of service. Support of multicast capabilities will be a crucial issue. The service platform is being implemented to run on top of different high-speed networks, including FDDI and DQDB     

Dynamic network layer for data query in sensor network

Query processing systems in wireless sensor networks usually support tasks such as data acquisition, data aggregation, and event‐based query. The performances of query processing with these tasks are greatly varied according to different routing protocols. Most existing data query systems usually use one routing protocol to deal with all kinds of queries. This work demonstrates that proper selection of routing protocols can improve the performance of query processing. We propose a dynamic routing layer that makes protocol selection on the basis of query tasks and can automatically switch between different routing protocols. Simulation results show that dynamic routing scheme is more energy efficient than single routing protocol. Copyright © 2012 John Wiley & Sons, Ltd.     

Application Oriented Multi Criteria Optimization in WSNs Using on AHP

With the increasing number and variety of Wireless Sensor Network (WSN) applications the need to define a suitable protocol design model that fits their specific requirements and operation has become even more pressing. The traditional methods and the well known OSI layered model prove to be inadequate for WSNs. Utilizing cross layer interactions on the other hand leads to increased efficiency in operation and prolonging the network lifetime. Similarly, proper optimization can even further add to improving the performance and reducing energy consumption in WSN. However there is no common ground to compare the suggested solutions or there is no well defined methodology for determining the optimization parameters for each specific case. In this paper we discuss two major issues: the first one is definition of optimization parameters for WSN and check for their consistency, the second one is how the suggested approach can be incorporated in a cross layer framework to provide adaptivity to different application requirements while maximizing the network performance and prolonging the network lifetime.     

A cross-layer optical circuit provisioning framework for data intensive IP end hosts

Using circuit-switched optical networks for next generation e-science applications is gaining increasing interest. In such applications, circuits are provisioned for end hosts to accomplish data-intensive or QoS-stringent communication tasks. Existing provisioning methods provide point-to-point connectivity for end hosts, that is, an established circuit connects one end host to another, and during the lifetime of the circuit, only communication tasks between the connected end hosts can be served. This inhibits circuits from being used in more general cases, where each end host communicates with different remote parities simultaneously through a single network interface. We propose V-STONES - a data flow-based VLAN tagging and switching technique to increase the connectivity of end host network interfaces in circuit-switched networks. With V-STONES, not only can an IP end host communicate with different remote systems concurrently through bandwidth guaranteed connections, but also protocol entities at different stack layers can talk to their counterparts through dedicated bandwidth pipes. In this article, we review the existing circuit provisioning methods and then discuss V-STONES and the architecture of cross-layer circuit provisioning for end hosts. We also introduce a prototype implementation in an optical network testbed and present the experimental results.     

防窃听数据链路安全协议的设计与实现

无论是软件捕包技术还是硬件捕包技术,前提是建立网络连接,恢复正确的时钟和数据流。针对网络窃听技术,提出并实现了可安全传输的数据链路协议,包括时钟协议和加密协议。协议采用插入式结构,不改变网络拓扑结构和驱动软件,易于扩展,可以适应不同层次、不同速率和不同介质的以太网物理层器件。协议单元可组合使用,在用户端和交换机端都易于实现。     

下一代无线网络中的跨层设计

下一代无线通信系统必须能够与互联网实现信息交互,这就需要利用通信协议来实现系统与其他通信系统间的互连互通。但是,现有通信协议基于OSI标准,其协议栈按照严格的分层方式工作,很难适应快速变化的无线通信环境。通过对现有协议栈进行改进,加入跨层设计方案则有助于改善下一代无线系统性能。文章简要分析了分层协议栈局限性,讨论了跨层设计原理,并系统地阐述了跨层设计时物理层、链路层、网络层、传输层和应用层协议应考虑的因素。     

B-ISDN and the OSI protocol reference model

The evolution of public telecommunication networks toward broadband integrated services digital networks (B-ISDNs) is presented. The asynchronous transfer mode (ATM), which supports B-ISDNs, and the B-ISDN protocol reference model are discussed. It is shown that the service offered by the ATM layer in the B-ISDN protocol reference model is equivalent to the service offered by the OSI physical layer. It is also shown that the service offered by the ATM adaptation layer (AAL) type 3/4 is similar to an OSI data link service. The emergence of the metropolitan area network (MAN) standard as an intermediate support for broadband services and the similarities between the DQDB MAC and the AAL type 3/4 in its connectionless mode are discussed     

Heterogeneity and OSI

A review is presented of the different aspects of heterogeneity that need to be resolved to achieve global interoperability, and specifically, to provide global transport service. The authors concentrate on the problems of interconnecting computer networks and systems that use different protocols, either different subsets of OSI (open systems interconnection) standards or OSI and non-OSI protocols. The issues of protocol conversion are discussed, and integrated naming, addressing, and directory mechanisms for interconnecting OSI and non-OSI domains are outlined. More subtle aspects of interoperability are examined for the case of the OSI transport protocol class 4 in mixed LAN/WAN (local-area-network/wide-area network) environments