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Chapter 1 Introduction to Computer Networks and Data Communications. Sender. Signal. Receiver. Transmission medium. Communication. The transmission of a signal by way of a medium from sender to receiver. Communication Problems. Completeness & comprehension Attenuation & noises
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Chapter 1Introduction to Computer Networks and Data Communications
Sender Signal Receiver Transmission medium Communication The transmission of a signal by way of a medium from sender to receiver
Communication Problems • Completeness & comprehension • Attenuation & noises • Competing resources • Routing & addressing • Security
Networks • Computer network • Voice network • Data network • Local area network • Metropolitan area network • Wide area network • Personal area network • Network management
Data Communications • Data Communications: • The movement of computer information (data) from one point to another by means of electrical or optical transmission systems • Is a sub-field of telecommunications • Telecommunications: • Includes the transmission of voice and video as well as data
Network Configurations • Microcomputer-to-local area network • Microcomputer-to-Internet • Local area network-to-local area network • Personal area network-to-workstation • Local area network-to-metropolitan area network • Local area network-to-wide area network • Wide area network-to-wide area network • Sensor-to-local area network • Satellite and microwave • Cell phones • Terminal/microcomputer-to-mainframe computer
Convergence • An Additional Basic Connection – telephone-to-network • Telephone systems are ubiquitous and now carry more data than voice • Common configuration – telephone connected to POTS • Newer configuration (VoIP) – telephone-to-LAN via gateway or telephone to gateway via DSL/cable
Network Components • Hardware • Computer • Network Interface Card (NIC) • Hub • Switch • Bridge • Router • Software • Network protocols
Network Architectures • A reference model that describes the layers of hardware and software necessary to transmit data between two points or for multiple devices / applications to interoperate • Reference models are necessary to increase likelihood that different components from different manufacturers will converse • Two models to learn: OSI model and TCP/IP protocol suite
Application (7) User input to host Presentation (6) Data coding, formatting Session (5) Begin, frames, end, rules Transport (4) End-to-end delivery Network (3) Message routing Datalink (2) Frame formatting, error Physical (1) Physical connections The OSI Model
Application Presentation Session Transport Network Datalink Physical OSI vs. The Internet Application Application Transport Transport Network Network Interface Network Access Physical
Application Application Presentation Presentation Session Session Transport Transport Network Network Datalink Datalink Physical Physical Logical vs. Physical Connection