Chapter 1. Introduction Data Communications Data Communications Networking Protocols and Protocol Architecture Standards Organizations Outline of the book

Data Communications

Data Comm. Networking

Wide-Area Networks Interconnected switching nodes Techniques Circuit switching Packet switching Frame relay ATM Networks ISDN, Broadband ISDN

Wide-Area Networks (cont) Circuit Switching dedicated communications path e.g. telephone network Packet Switching packets store-and-forward Frame Relay for high data rate and low error rate little overhead and error control up to 2Mbps

Wide-Area Networks (cont) ATM Networks cell relay evolution from Frame relay little overhead and error control variable length frames  fixed size cells evolution from Circuit switching constant-data-rate channel via packet switching tech. dynamic allocation of data rates 10s ~ 100s Mbps

Local Area Networks Key distinctions between LANs and WANs Different geographic scope  different tech. Greater data rates of LANs Ownership Broadcast network approach Switched LANs

Protocol Architecture Three layer model Computer 1 Computer 2 Application protocol Application Application Transport protocol Transport Transport Network access Network Network access Network access protocol

TCP/IP Protocol Architecture

OSI Layers Applications layer Presentation layer Session layer Transport layer Network layer Data link layer Physical layer

TCP/IP v.s. OSI Network Access

Standards Organizations IETF Internet Engineering Task Force subsidiary task force of IAB (Internet Architecture Board) Request for Comments (RFCs) ISO International Organization for Standardization U.S. member body: ANSI (American National Standards Institute)

Standards Organizations (cont) ITU-T ITU Telecommunications Standardization Sector replaces CCITT (International Telegraph and Telephone Consultative Committee) ATM Forum

Outline of the Book Protocols and Architecture Data Transmission OSI 7-layer RM TCP/IP model Data Transmission behavior of data signals Transmission Media guided or wireless Data Encoding analog and digital data/signal

Outline of the Book (cont) Data Communication Interface asynchronous and synchronous tx Data Link Control HDLC Multiplexing FDM, TDM Circuit Switching switch operations

Outline of the Book (cont) Packet Switching routing, congestion control Frame Relay, ATM LAN Technology and Systems LAN topologies Ethernet, Token Ring/Bus, FDDI, 100VG Bridges Interconnection of LANs

Outline of the Book (cont) Internetworking Internet Protocol (IP), IPv6, ICMP Routing protocols, IGMP, RSVP Transport Protocols TCP, UDP Network Security DES, RSA encryption algorithms

Outline of the Book (cont) Distributed Applications Network management World-wide web E-mail ISDN and B-ISDN