2 Introduction A WAN is a data communications network that covers a relatively broad geographic area and often uses transmission facilities provided by common carriers, such as telephone companies. WANs are used to connect LANs and other types of networks together, so that users and computers in one location can communicate with users and computers in other locations.
3 WAN technologies function at the lower three layers of the OSI reference model: the physical layer, the data link layer, and the network layer. The common LAN technologies operating at Layer 1/2 (such as the forms of Ethernet or Wifi) are often geared towards physically localised networks, and thus cannot transmit data over tens, hundreds or even thousands of miles or kilometres.
4 Introduction (cont.)
5 Introduction (cont.) Many WANs are built for one particular organization and are private. Others, built by Internet service providers, provide connections from an organization's LAN to the Internet. Several options are available for WAN connectivity: Leased line : Point-to-Point connection between two computers or Local Area Networks (LANs) Circuit switching : A dedicated circuit path is created between end points. Best example is dialup connections Packet switching : Devices transport packets via a shared single pointto-point or point-to-multipoint link across a carrier internetwork. Variable length packets are transmitted over Permanent Virtual Circuits (PVC) or Switched Virtual Circuits (SVC) Cell relay : Similar to packet switching, but uses fixed length cells instead of variable length packets. Data is divided into fixed-length cells and then transported across virtual circuits
6 Point-to-Point Links (Leased Line) A point-to-point link provides a single, preestablished WAN communications path from the customer premises through a carrier network, such as a telephone company, to a remote network. A point-to-point link is also known as a leased line because its established path is permanent and fixed for each remote network reached through the carrier facilities.
7 Point-to-Point Links (Leased Line) (cont.) A typical point-to-point link operates through a WAN to a remote network.
8 Point-to-Point Links (Leased Line) (cont.) WANs are often built using leased lines. At each end of the leased line, a router connects the LAN on one side with a second router within the LAN on the other. Leased lines can be very expensive. Instead of using leased lines, WANs can also be built using less costly circuit switching or packet switching methods.
9 Point-to-Point Links (Leased Line) (cont.) A leased line, a type of dedicated line, is a permanent fiber optic or telephone line connection between two points set up by a telecommunications carrier. It can be used for telephone, data, or Internet services. Often, businesses will use a leased line to connect geographically distant offices because it guarantees bandwidth for network traffic. For example, a bank may use a leased line in order to easily transfer financial information from one branch office to another. Both long and short distances can be spanned by a leased line, and customers generally pay a flat monthly rate for the service.
10 Point-to-Point Links (Leased Line) (cont.)
11 Point-to-Point Links (Leased Line) (cont.)
12 Point-to-Point Links (Leased Line) (cont.) Leased lines do not have telephone numbers because each side of the line is always connected to the other. The information sent through a leased line travels along dedicated secure channels, eliminating the congestion that occurs in shared networks. Connection speeds can range from 64 kilobits per second (Kbps) to 10 gigabits per second (Gbps). The advantage of Leased Line is that it is the most secure connection and its disadvantage is that it is expensive.
13 Circuit Switching Circuit switching is a WAN switching method in which a dedicated physical circuit is established, maintained, and terminated through a carrier network for each communication session. Circuit switching is a WAN connectivity technique that allows circuits to be created across a network on demand, and then terminated once they are no longer required.
14 Circuit Switching (cont.) The perfect example of circuit switching in action is a normal telephone call after you pick up the phone and dial a number, a circuit is created between your phone and the phone of the person you are calling. Used extensively in telephone company networks, circuit switching operates much like a normal telephone call. Dial-up and Integrated Services Digital Network (ISDN) is an example of a circuit-switched WAN technology
15 Circuit Switching (cont.) Circuit switching is commonly used to interconnect networks in cases where a permanent connection is not required. For example, a company might need to transfer data to a branch office just once or twice a day. In cases such as this, the cost of a permanent link wouldn t be justified. While beneficial in cases where data traffic requirements are low, circuit switched connections generally provide slower throughput rates than other technologies.
16 Circuit Switching (cont.) Dial-up Internet access is a form of Internet access that uses the facilities of the public switched telephone network (PSTN) to establish a dialled connection to an Internet service provider (ISP) via telephone lines. The user's computer or router uses an attached modem to encode and decode Internet Protocol packets and control information into and from analogue audio frequency signals, respectively.
17 Circuit Switching (cont.) Integrated Services Digital Network (ISDN) is a set of communications standards for simultaneous digital transmission of voice, video, data, and other network services over the traditional circuits of the public switched telephone network. It has been available for over a decade. With ISDN, voice and data are carried by bearer channels (B channels) occupying a bandwidth of 64 kb/s (bits per second).
18 Circuit Switching (cont.) A circuit- switched WAN undergoes a process similar to that used for a telephone call.
19 Packet Switching Packet switching is a WAN switching method in which network devices share a single point-to-point link to transport packets from a source to a destination across a carrier network. Packet switching is a technology that splits data in network communications into manageable small pieces, called packets. To be able to understand packet-switching, you need to know what a packet is. The Internet Protocol(IP), just like many other protocols, breaks data into chunks and wraps the chunks into structures called packets. Each packet contains, along with the data load, information about the IP address of the source and the destination nodes, sequence numbers and some other control information. A packet can also be called a segment or datagram.
20 Packet Switching (cont.) By sending a large file in several small chunks over a network, packet switching minimizes the impact of data transmission errors. Statistical multiplexing is used to enable devices to share these circuits. Asynchronous Transfer Mode (ATM), Frame Relay, Switched Multimegabit Data Service (SMDS), and X.25 are examples of packetswitched WAN technologies
21 Packet Switching (cont.) Packet switching transfers packets across a carrier network.
22 Packet Switching (cont.) Circuit switching is old and expensive, and it is what PSTN uses. Packet switching is more modern. When you are making a PSTN call, you are actually renting the lines, with all it implies. See why international calls are expensive? So if you speak for, say 10 minutes, you pay for ten minutes of dedicated line. You normally speak only when your correspondent is silent, and vice versa. Taking also into consideration the amount of time no one speaks, you finally use much less than half of what you are paying for. With VoIP, you actually can use a network or circuit even if there are other people using it at the same time. There is no circuit dedication. The cost is shared.
23 Packet Switching (cont.) Circuit-switching is more reliable than packet-switching. When you have a circuit dedicated for a session, you are sure to get all information across. When you use a circuit which is open for other services, then there is a big possibility of congestion (which is for a network what a traffic jam is for the road), and hence the delays or even packet loss. This explains the relatively lower quality of VoIP voice compared to PSTN. But you actually have other protocols giving a helping hand in making packet-switching techniques to make connections more reliable. An example is the TCP protocol. Since voice is to some extent tolerant to some packet loss (unless text - since a comma lost can mean a big difference), packet-switching is finally ideal for VoIP.
24 Packet Switching (cont.) A type of communications in which a dedicated channel (or circuit) is established for the duration of a transmission. The most ubiquitous circuitswitching network is the telephone system, which links together wire segments to create a single unbroken line for each telephone call. The other common communications method is packet switching, which divides messages into packets and sends each packet individually. The Internet is based on a packet-switching protocol, TCP/IP. Circuit-switching systems are ideal for communications that require data to be transmitted in real-time. Packet-switching networks are more efficient if some amount of delay is acceptable. Circuit-switching networks are sometimes called connection-oriented networks. Note, however, that although packet switching is essentially connectionless, a packet switching network can be made connectionoriented by using a higher-level protocol. TCP, for example, makes IP networks connection-oriented.
25 WAN Virtual Circuits A virtual circuit is a logical circuit created to ensure reliable communication between two network devices. Two types of virtual circuits exist: switched virtual circuits (SVCs) and permanent virtual circuits (PVCs). SVCs are virtual circuits that are dynamically established on demand and terminated when transmission is complete. Communication over an SVC consists of three phases: circuit establishment, data transfer, and circuit termination. A PVC is a permanently established virtual circuit that consists of one mode: data transfer. PVCs are used in situations in which data transfer between devices is constant.
26 WAN Dialup Services Dialup services offer cost-effective methods for connectivity across WANs. Two popular dialup implementations are dial-on-demand routing (DDR) and dial backup. DDR is a technique whereby a router can dynamically initiate and close a circuit-switched session as transmitting end station demand. Dial backup is a service that activates a backup serial line under certain conditions. The secondary serial line can act as a backup link that is used when the primary link fails or as a source of additional bandwidth when the load on the primary link reaches a certain threshold. Dial backup provides protection against WAN performance degradation and downtime.
27 WAN Devices WANs use numerous types of devices that are specific to WAN environments. WAN switches, access servers, modems, CSU/DSUs, and ISDN terminal adapters are discussed in the following sections.
28 WAN Devices (cont.) A WAN switch is a multiport internetworking device used in carrier networks. These devices typically switch such traffic as Frame Relay, X.25, and SMDS and operate at the data link layer of the OSI reference model.
29 WAN Devices (cont.) An access server acts as a concentration point for dial-in and dial-out connections.
30 WAN Devices (cont.) A modem is a device that interprets digital and analog signals, enabling data to be transmitted over voice-grade telephone lines. At the source, digital signals are converted to a form suitable for transmission over analog communication facilities. At the destination, these analog signals are returned to their digital form.
31 WAN Devices (cont.) A channel service unit/digital service unit (CSU/DSU) is a digital-interface device (or sometimes two separate digital devices) that adapts the physical interface on a data terminal equipment (DTE) device (such as a terminal) to the interface of a data circuit-terminating (DCE) device (such as a switch) in a switched-carrier network. The CSU is responsible for the connection to the telecom network while the DSU is responsible for handling the interface with the DTE. The CSU/DSU also provides signal timing for communication between these devices.
32 WAN Devices (cont.) The CSU/DSU stands between the switch and the terminal.
33 WAN Devices (cont.) An ISDN terminal adapter is a device used to connect ISDN Basic Rate Interface (BRI) connections to other interfaces, such as EIA/TIA-232. A terminal adapter is essentially an ISDN modem.
CHAPTER 3 Introduction to WAN Technologies This chapter introduces the various protocols and technologies used in wide- area network (WAN) environments. Topics summarized here include point-to-point links,
WAN Data Link Protocols In addition to Physical layer devices, WANs require Data Link layer protocols to establish the link across the communication line from the sending to the receiving device. 1 Data
WAN Review A WAN makes data connections across a broad geographic area so that information can be exchanged between distant sites. This topic defines the characteristics of a WAN. WAN Overview WANs connect
CTS2134 Introduction to Networking Module 07: Wide Area Networks WAN cloud Central Office (CO) Local loop WAN components Demarcation point (demarc) Consumer Premises Equipment (CPE) Channel Service Unit/Data
Chapter 2 - The TCP/IP and OSI Networking Models TCP/IP : Transmission Control Protocol/Internet Protocol OSI : Open System Interconnection RFC Request for Comments TCP/IP Architecture Layers Application
Connection Services Hakim S. ADICHE, MSc firstname.lastname@example.org Department of Computer Engineering King Fahd University of Petroleum and Minerals Dhahran, Saudi Arabia Connection Services Different connectivity
Chapter 11: WAN Abdullah Konak School of Information Sciences and Technology Penn State Berks Wide Area Networks (WAN) The scope of a WAN covers large geographic areas including national and international
Network+ Guide to Networks 6 th Edition Chapter 7 Wide Area Networks Objectives Identify a variety of uses for WANs Explain different WAN topologies, including their advantages and disadvantages Compare
CHAPTER 1 Introduction to WANs Objectives After completing this chapter, you should be able to answer the following questions: How does the Cisco enterprise architecture provide integrated services over
WAN Technologies Based on CCNA 4 v3.1 Slides Compiled & modified by C. Pham 1 Wide-area Networks (WANs) 2 Metropolitan-Area Network (MANs) 3 Path Determination 4 Internetworking Any internetwork must include
Computer Networks Lecture 06 Connecting Networks Kuang-hua Chen Department of Library and Information Science National Taiwan University Local Area Networks (LAN) 5 kilometer IEEE 802.3 Ethernet IEEE 802.4
Review questions 1 Which network type is a specifically designed configuration of computers and other devices located within a confined area? A Peer-to-peer network B Local area network C Client/server
Previous screen 51-10-50 Circuit-Switched Router Connections Nathan J. Muller Payoff LAN managers will find that routers supporting dial backup, bandwidth-on-demand, and dial-on-demand enable more flexible
Overview of WAN Connections Module 1 Objectives This module introduces the basic elements of WAN connections and describes the role each element plays in creating that connection. After completing this
Introduction Computer Network. Interconnected collection of autonomous computers that are able to exchange information No master/slave relationship between the computers in the network Data Communications.
Chapter 1 Review Questions R1. What is the difference between a host and an end system? List several different types of end systems. Is a Web server an end system? 1. There is no difference. Throughout
Voice and Delivery Data Networks Chapter 11 Learning Objectives After reading this chapter, you should be able to: Identify the basic elements of a telephone system Describe the composition of the telephone
Videoconferencing Glossary Algorithm A set of specifications that define methods and procedures for transmitting audio, video, and data. Analog Gateway A means of connecting dissimilar codecs. Incoming
MANAGEMENT INFORMATION SYSTEMS 8/E Raymond McLeod, Jr. and George Schell Chapter 10 Data Communications Copyright 2001 Prentice-Hall, Inc. 10-1 Objectives Understand data communication basics. Know the
School of Business Eastern Illinois University Telecommunications systems (Part 1) (Week 11, Thursday 11/02/2006) Abdou Illia, Fall 2006 Learning Objectives 2 Describe and compare types of connection to
Internet Protocol (IP)/Intelligent Network (IN) Integration Tutorial Definition Internet telephony switches enable voice calls between the public switched telephone network (PSTN) and Internet protocol
CHAPTER 2 Connecting to the WAN Objectives Upon completion of this chapter What is the purpose of a WAN? How does a circuit-switched network differ from a packet-switched network? How do service provider
Communication Networks MAP-TELE 2011/12 José Ruela Network basic mechanisms Introduction to Communications Networks Communications networks Communications networks are used to transport information (data)
Internet Public Network Bandwidth Data rate measured in bits (not bytes) per seconds Kbps (Kilobits per seconds) 125 chars/sec Mbps (Megabits per seconds) 1,250 chars/sec Gbps (Gigabits per seconds) 12,500
WANs and Routers M.Sc. Aleksandra Kanevce M.Sc. Aleksandra Bogojeska 1 Introduction to WANs A WAN is a data communications network that spans a large geographic area such as a state, province, or country.
1 Introduction to mobile telecommunications Mobile phones were first introduced in the early 1980s. In the succeeding years, the underlying technology has gone through three phases, known as generations.
ADSL or Asymmetric Digital Subscriber Line Backbone Bandwidth Bit Commonly called DSL. Technology and equipment that allow high-speed communication across standard copper telephone wires. This can include
Requirements of Voice in an IP Internetwork Real-Time Voice in a Best-Effort IP Internetwork This topic lists problems associated with implementation of real-time voice traffic in a best-effort IP internetwork.
Basic Networking Concepts 1. Introduction 2. Protocols 3. Protocol Layers 4. Network Interconnection/Internet 1 1. Introduction -A network can be defined as a group of computers and other devices connected
Building integrated services intranets A White Paper from Inalp Networks Inc Meriedweg 7 CH-3172 Niederwangen Switzerland http://www.inalp.com CONTENTS CONTENTS...2 1 EXECUTIVE SUMMARY...3 2 INTRODUCTION...4
Packet Switching and Computer Networks Switching As computer networks became more pervasive, more and more data and also less voice was transmitted over telephone lines. Circuit Switching The telephone
Lecture Computer Networks Prof. Dr. Hans Peter Großmann mit M. Rabel sowie H. Hutschenreiter und T. Nau Sommersemester 2012 Institut für Organisation und Management von Informationssystemen Asynchronous
Glossary of Telco Terms Access Generally refers to the connection between your business and the public phone network, or between your business and another dedicated location. A large portion of your business
White Paper and -Based : A Comparison of Technologies Larry Greenstein Nuera Communications VP, Technology, Forum June 1995 June 27, 1995 i TABLE OF CONTENTS 1. PREFACE...1 2. INTRODUCTION...1 3. INTERWORKING
3.1 TELECOMMUNICATIONS, NETWORKS AND THE INTERNET The Business Value of Telecommunications and Networking Business value impacts of the telecommunications and Networking are: Declining transaction costs
Region 10 Videoconference Network (R10VN) Network Considerations & Guidelines 1 What Causes A Poor Video Call? There are several factors that can affect a videoconference call. The two biggest culprits
Chapter 7: Computer Networks, the Internet, and the World Wide Web Invitation to Computer Science, C++ Version, Third Edition Objectives In this chapter, you will learn about: Basic networking concepts
KEY VOIP TERMS 1 ACD: Automatic Call Distribution is a system used to determine how incoming calls are routed. When the ACD system receives an incoming call it follows user-defined specifications as to
Lecture 11: ISDN & ATM CS 5516 Computer Architecture Networks VA Tech Prof. Roy M. Wnek History of ISDN Traditionally, local loop connectivity has been with an analog signal on copper Inefficient, prone
TAXONOMY OF TELECOM TERMS Prepared by TUFF Ltd This short taxonomy is designed to describe the various terms used in today s telecommunications industry. It is not intended to be all embracing but to describe
51-10-32 Frame Relay Testing and Training Steve Greer Peter Luff Sean Yarborough Payoff Because it provides efficient, cost-effective transfer of bursty, bandwidth-intensive applications, frame relay is
1 TCP Transmission Control Protocol, is a connection based Internet protocol responsible for breaking data into packets to send over a network using IP (internet protocol) IP works at the TCP/IP Internet
White Paper Dedicated Access Solutions for Internet Service Providers INTRODUCTION Revenue from business connections to the Internet represents, on average, almost 60 percent of the total revenue to Internet
11/22/2013 1 Week3-4 Point-to-Point, LAN, WAN Review 11/22/2013 2 What will you learn? Representatives for Point-to-Point Network LAN Wired Ethernet Wireless Ethernet WAN ATM (Asynchronous Transfer Mode)
2007 Cisco Systems, Inc. All rights reserved. DESGN v2.0 3-11 Enterprise Campus and Data Center Design Review Analyze organizational requirements: Type of applications, traffic volume, and traffic pattern
DL TC72 Communication Protocols: HDLC, SDLC, X.25, Frame Relay, ATM Objectives: Base training of an engineer for the installation and maintenance of Digital Telecommunications and Internetworking systems.
POZNAN UNIVE RSITY OF TE CHNOLOGY ACADE MIC JOURNALS No 80 Electrical Engineering 2014 Assaid O. SHAROUN* VOICE OVER IP AND NETWORK CONVERGENCE As the IP network was primarily designed to carry data, it
NXU RoIP Link to Eliminate Voice-Grade Leased Line Purpose This Application Note will describe a method at which Network Extension Units (NXUs) can be utilized on an existing digital network to eliminate
TABLE OF CONTENTS TABLE OF CONTENTS...4-495 4.7 VIDEO NETWORKING...4-497 4.7.1 Current Network Overview...4-497 4.7.2 Proposed Video Network...4-497 LIST OF FIGURES Figure 18.104.22.168.3-1 Video Implementation
School of Business Eastern Illinois University Telecommunications systems (Part 2) Abdou Illia, Spring 2007 (Week 12, Thursday 3/29/2007) T-1 Digital Subscriber Line (DSL) Cellular Telephone System Integrated
Network Technologies Telephone Networks IP Networks ATM Networks Three Network Technologies Telephone Network The largest worldwide computer network, specialized for voice ing technique: Circuit-switching
Abstract The evolution of TETRA networks towards an all- IP architecture is now a reality and has been accepted by even the most demanding users of TETRA technology. Although circuit switch based TETRA
Page 1 of 8 Computer Networking Networks 9.1 Local area network A local area network (LAN) is a network that connects computers and devices in a limited geographical area such as a home, school, office
Technical Glossary from Frontier A Analogue Lines: Single Analogue lines are generally usually used for faxes, single phone lines, modems, alarm lines or PDQ machines and are generally not connected to
Gen2 Ventures White Paper Clearing the Way for VoIP An Alternative to Expensive WAN Upgrades Executive Overview Enterprises have traditionally maintained separate networks for their voice and data traffic.
What You Will Learn About Computers Are Your Future Chapter 8 Networks: Communicating and Sharing Resources Basic networking concepts Advantages and disadvantages of networks Peer-to-peer and client/server
Data Communication Networks and Converged Networks The OSI Model and Encapsulation Layer traversal through networks Protocol Stacks Converged Data/Telecommunication Networks From Telecom to Datacom, Asynchronous
Computer Networks A group of two or more computer systems linked together. There are many [types] of computer networks: Peer To Peer (workgroups) The computers are connected by a network, however, there
Islamic University of Gaza Faculty of Engineering Computer Engineering Department Networks Discussion ECOM 4021 Lecture # 2 CH1 Computer Networks and the Internet By Feb 2013 (Theoretical material: page
COMPANY First Revised Sheet 1 High Point, North Carolina Canceling Original Sheet 1 Effective: October 15, 2009 10.1 FRAME RELAY SERVICE 1 10.1.1 GENERAL 1 10.1.2 REGULATIONS 1 10.1.3 EXPLANATION OF TERMS
Leased Line + Remote Dial-in connectivity Client: One of the TELCO offices in a Southern state. The customer wanted to establish WAN Connectivity between central location and 10 remote locations. The customer
Management Information Systems Basics of the Internet Dr. Shankar Sundaresan (Adapted from Introduction to IS, Rainer and Turban) Internet Basics Outline Internet History Internet Structure Switching Methods
VoIP Glossary Analog audio signals: Analog audio signals are used to transmit voice data over telephone lines. This is done by varying or modulating the frequency of sound waves to accurately reflect the
WAN and VPN Solutions: Choosing the Best Type for Your Organization xo.com WAN and VPN Solutions: Choosing the Best Type for Your Organization WAN and VPN Solutions: Choosing the Best Type for Your Organization
Data Link Protocols Relates to Lab. This module covers data link layer issues, such as local area networks (LANs) and point-to-point links, Ethernet, and the Point-to-Point Protocol (PPP). 1 TCP/IP Suite
920-803 - technology standards and protocol for ip telephony solutions 1. Which CODEC delivers the greatest compression? A. B. 711 C. D. 723.1 E. F. 726 G. H. 729 I. J. 729A Answer: C 2. To achieve the
This white paper provides an overview of voice and data convergence. It discusses enabling business drivers and technical factors, such as compression techniques and QOS parameters, that have complemented
Networks 2 Gabriela Ochoa Lecture Networks 2/Slide 1 Content How is Internet connected? Internet backbone Internet service providers (ISP) How to connect a home computer to the Internet? How do networks
FREE FREE One One Hour Hour VoIPonline VoIPonline Seminar TM Seminar TM For additional information contact: Terry Shugart - email@example.com http://www.analogic.com/cti TEL: 978-977-3000 FAX: 978-977-6813
Protocols and Architecture Protocol Architecture. Layered structure of hardware and software to support exchange of data between systems/distributed applications Set of rules for transmission of data between
Lecture 6 Long Distance Connection and WAN Digital Telephone, PCM and Nyquist Sampling Theorem DSU/CSU, T Line Series and OC line Series Local Loop DSL Technologies - ADSL, HDSL, SDSL, VDSL Cable Modem
Concepts to know: IST 220 Exam 3 Notes Prepared by Dan Veltri The Final Exam is scheduled for Wednesday, December 15 th from 4:40PM 6:30 PM in 112 Chambers. Chapters covered: 12, 13, 15, 16, 17, 18, 20,
Guidelines on International Gateway Access and Voice over Internet Protocol (VoIP) Issued by the Nigerian Communications Commission 1. Background (1) The Nigerian Communications Commission ( the Commission
CSCI 491-01 Topics: Internet Programming Fall 2008 Introduction Derek Leonard Hendrix College September 3, 2008 Original slides copyright 1996-2007 J.F Kurose and K.W. Ross 1 Chapter 1: Introduction Our