NET 331 Computer Networks Lecture 01 Introduction to Computer Networks Dr. Anis Koubaa Reformatted slides from textbook Data and Computer Communications, Ninth Edition by William Stallings, 1 (c) Pearson Education - Prentice Hall, 2011 - Original Slides from Dr. Lawrie Brown 28-Jan-12 Data Communications, Data Networks, and the Internet The fundamental problem of communication is that of reproducing at one point either exactly or approximately a message selected at another point - The Mathematical Theory of Communication, Claude Shannon Message Message ا ا م ات ھ ا خ ات ط إ ا أو ر ن ر #ددة ط أرى 2
Learning Outcome Understand what a network is Learn how do networks work Get a basic understand of what the Internet is Understand basic concepts of data communication 3 Whatisa Network?
Whatisa Network? Railway & Metro Network 5 Whatisa Network? Highway Network 6
Whatisa Network? Plumbing Network 7 Whatisa Network? Spider Net(work) 8
What is a Network? A Network is A system of lines/channel that are interconnected together What is a Computer Network? 9 Computer Networks
What is a (Computer) Network? 11 Data Centers Entreprise/University Network Data Center 12
Home Computer Networks Home Network 13 Wide Area Networks (Reference: CISCO) MPLS Use Case Requirements: L2 pt-pt, L2 fully meshed,l3 fully meshed sites through HQ site, all sites directly access Hosted content and the Internet with SLA CustomerA HQ A Remote Users/ Telecommuters VPN B VM VPN A Local or Direct Dial ISP FR/ATM/ Carrier Ethernet Provider Networks Internet Shared/Managed Services Video Hosted ERP Server Content PE1 MPLS to IPsec/PE PE5 PE3 MPLS Backbone P1 P3 P2 P4 PE2 Mobile Backhaul PE4 VM VPN A VPN Branch B Office VM VPN C VM Mobile Backhaul HQ B VPN B BRKRST-1101 14415_04_2008_c2 VPN C HQ C 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 6 14
Questions Addresses in this Course? How communication is possible between two computers? How computers are interconnected together? How to send data message from one computer to another? How to know the location of the destination? How to know that a message is delivered or not? 15 Communication Model How Communication is possible between two computers? Section 1.2, Data and Computer Communications
Communications Model 17 Communications Tasks Transmission system utilization Addressing Interfacing Signal generation Synchronization Exchange management Error detection and correction Routing Recovery Message formatting Security Network management Flow control 18
Data Communications How Communication is possible between two computers? Section 1.3, Data and Computer Communications Data Communications Model 20
Transmission Lines The basic building block of any communications facility is the transmission line. The business manager is concerned with a facility providing the required capacity, with acceptable reliability, at minimum cost. Capacity Reliability Cost Transmission Line 21 Transmission Mediums Two mediums currently driving the evolution of data communications transmission are: Fiber optic transmissions Wireless transmissions There are others Cables 22
Networking How computers are interconnected together? Section 1.4, Data and Computer Communications Networking Need for networks Large number of computers (fully mesh is not practical) Different types of information/messages Data integration Voice Data Fully Mesh Network Image Video 24
LANs and WANs There are two broad categories of networks Local Area Networks (LAN) Wide Area Networks (WAN) 25 Wide Area Networks (WANs) Span a large geographical area Require the crossing of public right-of-ways Rely in part on common carrier circuits Typically consist of a number of interconnected switching nodes 26
Wide Area Networks Alternative technologies used include: Circuit switching Packet switching Frame relay Asynchronous Transfer Mode (ATM) Multiple Label Protocol Switching (MPLS) 27 Circuit Switching Uses a dedicated communications path Connected sequence of physical links between nodes Logical channel dedicated on each link Rapid transmission The most common example of circuit switching is the telephone network 28
Packet Switching Data are sent out in a sequence of small chunks called packets Packets are passed from node to node along a path leading from source to destination Packet-switching networks are commonly used for terminal-to-terminal computer and computer-tocomputer communications 29 Local Area Networks (LAN) Smaller scope, typically a single building LANs are usually owned by the same organization that owns attached devices LAN Internal data rates greater than WANs Most common configurations are switched LANs and wireless LANs 30
Metropolitan Area Networks (MAN) Covers a geographic area such as a town, city or suburb Middle ground between LAN and WAN MAN Supports both data and voice Private or public network 31 The Internet Internet evolved from ARPANET Developed to solve the dilemma of communicating across arbitrary, multiple, packet-switched network TCP/IP provides the foundation 32
Internet Key Elements 33 Internet Architecture 34
Internet Terminology 35 A Networking Configuration 36
Summary Trends challenging data communications: traffic growth development of new services advances in technology Transmission mediums fiber optic wireless Network categories: WAN LAN Internet evolved from the ARPANET TCP/IP foundation 37