Enterprise NetworksII: Wide Area Networks

Early data networks were based on point-to-point or multipoint topologies. They were often of a star structure with a central processing unit (CPU) at the star's hub. Terminals in this network were “dumb” terminals and relied on the CPU's processing power for nearly all network activity. When the personal computer (PC) gained wide acceptance, distributed processing became the rule. As a result, data networks and data networking became much more complex. We now see complex multiple star, mesh, and tree like networks where many of the nodes have multiple inlets and outlets. Data rates were based on the limitations of the analog network. In the period of the 2nd edition of this book, this roughly equated to 9600 bps. Today, it is common to have 56-kbps access lines to a larger network where the basic channel data rate is 64 kbps. We can bring together these basic building blocks of 64 kbps to form aggregate channels of 128, 256, and 384 kbps up to 1.536 Mbps or 1.984 Mbps. Data protocols instilled order out of contentious chaos in data network operation. These protocols, applying to wide area networks (WANs), are the principal thrust of the chapter. Most are based on shipping user data in packets or frames. We discuss the transport of user data in cells in Chapter 28. Most packet networks are based on CCITT Rec. X.25. If we widen the definition of packet networks to include the transmission control protocol/internet protocol (TCP/IP), certainly X.25 will have a competitor. Both TCP/IP and X.25 have a comparatively high latency (latency is the time it takes from initiation to completion of a data transaction). Frame relay was introduced in the same period. This is a comparatively low latency system. This section provides design data and brief descriptions of wide area data networking as a whole with hypothetical reference circuits, the archetypical data link layer protocol, high-level data link control (HDLC), X.25 and its companion, link access protocol B-layer (LAPB), TCP/IP family of protocols, frame relay family of protocols, and a brief description of SMDS (switched multimegabit data service). Variants of LAPD are discussed in the frame relay section of this chapter. Keywords: enterprise networks; universal application; high-level data-link control; packet-switched; virtual connections; transmission control protocol; internet protocol; ISO transport protocol; frame relay; switched multimegabit data service; internetworking; ITU-T rec X.75; data network management

In previous chapters, the local applications and services of UNIX in individual computers have been introduced. This chapter will present the remote and network functions and services of UNIX in servers and workstations. After explanation of general concepts about the Internet and computer networking, Transmission Control Protocol/Internet Protocol (TCP/IP) suit will be presented, and contents associated with layers of TCP/IP model from down to up will be discussed. Finally, we will explain how to use some commands in the application layer of the TCP/IP model, such as telnet, ping, ftp, etc.

Chapter 3 - The Internet and TCP/IP

Products in brief

4 - Packet Technologies

Named data networking (NDN) is a new and promising Internet architecture, which aims to replace the current transmission control protocol/Internet protocol (TCP/IP)-based Internet. The NDN internet architecture has introduced several benefits in numerous applications. An NDN-based indoor positioning and navigation system can further optimize existing localization technologies with reduced the server load and faster response time. In this study, an NDN-based approach for the existing Wi-Fi fingerprinting-based indoor positioning and navigation was investigated. Among the many features of NDN, the network-level caching can reduce the computational load and response time of the localization and navigation server. The theoretical analysis of the runtime complexity shows that the NDN's network-level caching performance is better than those of the conventional algorithms. In this paper, naming methods for different services and a server-side algorithm for handling the NDN requests are proposed. The real-world implantation and testing results show a better overall performance than that of TCP/IP. This network-level optimization for indoor positioning and navigation opens new opportunities because it can be combined with other application-level optimization techniques for more efficient indoor positioning and navigation in the future.

The transmission of huge amounts of data generated from various sensors is the basis and prerequisite for the analysis and prediction of the marine ecosystem. The special geographical conditions of the ocean determine that its data transmission is different from the common terrestrial data transmission. In this study, a marine environmental monitoring network architecture is proposed to collect environmental data from marine ecosystems using a heterogeneous network constructed by a multi-hop network and a satellite network. Considering the characteristics of satellite networks, such as high bandwidth delay product (BDP), long latency and high bit error rate, this work proposes a transmission scheme that improves the transmission performance of Transmission Control Protocol/Internet Protocol (TCP/IP)-based Internet networks over satellite networks. The improved scheme increases the monitoring data transmission rate, distinguishes between random data loss and congested data loss, rationalizes the threshold in fast recovery, and improves the overall transmission performance of the marine environmental monitoring network. The experimental results show that the proposed scheme can greatly improve the transmission performance of the monitoring network compared with traditional transmission protocols. The network model proposed in this study makes full use of current advanced network technologies, including multi-hop networks, wireless sensor networks, and satellite networks to expand the monitoring area at sea. This study provides a useful reference for the network model and data transmission for ocean monitoring.

Westnet

One of the main communication protocols used for transmitting PMU data packets are Transmission Control Protocol/ Internet Protocol (TCP/IP) and User Datagram Protocol/Internet protocol (UDP/IP). This paper aims at presenting the implementation and simulation of a communication network for wide area monitoring system. The main purpose is to send real data recorded from PMUs over communication network using both protocols and compare their performance in terms of data transmission reliability.

Chapter 12 - Frame Relay

We study infrastructure-based vehicular data networking for autonomous highway transportation systems. The infrastructure backbone consists of roadside units (RSUs) that act as access points for vehicles traveling along a segment of a highway system. The RSUs are interconnected by high-capacity point-to-point links. It is assumed that RSU transmissions reach all vehicles traveling along the highway. We present a data networking protocol that enables geocasting so that source vehicles aim to disseminate their data packets to vehicles that travel within a specified span from them. The dissemination route includes vehicle-to-infrastructure (V2I) and infrastructure-to-vehicle (I2V) wireless communication uplinks and downlinks. We study the performance behavior of the synthesized data network as a function of the average inter-RSU distance (i.e., the density of the RSU backbone). An IEEE 802.11p Medium Access Control (MAC) scheduling scheme is used for vehicles and RSUs to efficiently share the system's communications links. The data networking parameters configured for the synthesized network include the employed Modulation/Coding Schemes (MCS), the corresponding data rates, and vehicular and RSU transmit power levels. We evaluate the system's data throughput performance behavior, subject to the requirement that prescribed packet delay and delivery rate performance objectives are met. We show that system performance can be enhanced by the proper setting of vehicular and RSU transmit power levels. We provide analytical approximation to the effective transmit power levels, and verify them through simulation.

The authors begin with a discussion of the criteria for evaluating wide-area networks (WANs) used to interconnect remote bridges. Then they assess various WANs, point out the advantages of frame relaying, and describes this experience with operating implementation interconnecting token-rings via a prototype frame relay. The quality of a bridge service is considered to be the quality of MAC (media access control) service as seen by end-stations on different LANs that are bridged either directly by a single bridge or indirectly via multiple bridges and associated LANs. It depends critically on the route (which is dependent on the network topology) between the source and destination LANs and the quality of service provided by the individual brides and, in the case of remote bridges, WANs along the route.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Frame Relay (FR) was one of the most popular wide area networks (WANs) services deployed over the past few decades. FR is a high-performance WAN protocol that operates at the data link layer. FR is an example of a packet-switched technology, where the end stations are enabled to dynamically share the network medium and the allocated bandwidth. In a sequel, due to such attributes further to the lower cost and privacy (security), it is deployed widely in various organizations, companies, banks, or institutions as a main backbone technology to connect their local area networks (LANs) over different sites. In this work, the utilisation of FR technology among the LANs of some Iraqi universities is presented. Consequently, bandwidth-on-demand will be provided for the end and intermediate systems of each individual LANs. In addition, ports and expensive communications facilities that are required to interconnect the devices of these LANs are reduced. The configuration of frame relay among routers has been simulated using a Packet tracer, which is one of the professional software that can be utilized to implement networks along with their technologies.

Chapter 7 - Domain 7: Telecommunications and Network Security

Recent demands on affordable, portable wireless communication and computation devices have resulted in exponential growth of wireless networks ranging from Wireless Local Area Networks (WLAN) and Wireless Wide Area Networks (WWAN) to Ad-Hoc and Sensor networks. The major goal of wireless communication is to allow users to communicate together and to have access to global network anytime anywhere. This has led to wide acceptance of infrastructure based cellular networks (WWANs) where mobile stations communicate with a centralized controller, often referred as Access Point (AP) that is connected to the wired networks. On the other hand, WLANs have appeared as dominant popular technologies in many venues including a local area such as an academic campus or an airport terminal. These wireless networks mostly rely on IEEE 802.11 Wi-Fi (Wireless Fidelity) technology and its various derived versions (i.e. 802.11a,b,g). IEEE 802.11 standard supports two operational modes: The infrastructure-based Wireless Local Area Networks (WLANs) and an infrastructure-less Ad-Hoc Networks. A WLAN (Conti, 2003) typically imposes the existence of an AP and normally is connected to the wired networks to provide internet access for mobile devices. Obviously, only one hop link is needed to communicate between mobile devices and AP. In contrast, there is no AP or infrastructure in Ad-Hoc networks. Any two stations can communicate directly when they are in the range of reception of each other. To this end, the stations may use multi-hop routing to deliver their packets to destinations. The ad-hoc protocols (Conti, 2003; Mohapatra & Krishnamurthy, 2005) are self-configured for address and routing in the face of mobility and the network topology may change in each configuration. The multi-hop wireless ad-hoc networks, or multi-hop wireless networks enable wireless networking in the environments where the wired or cellular connections are impossible, inadequate, or cost effective (e.g. battle field, disaster recovery, etc.). The popularity of internet over the last decades has resulted in rapid advancement of demanding applications. The Transmission Control Protocol/Internet Protocol (TCP/IP) (Stevens, 1994) is a well-known de facto protocol in developing today’s internet. Basically, TCP provides a connection-oriented and reliable end-to-end data delivery between two hosts in traditional wired networks. Since TCP is well tuned and due to its wide acceptance in internet, it is desirable to extend and adopt its functionality to wireless networks. On the