Broadband transmission: the data is modulates into a carrier wave. Broadband transmission has a much greater band width than baseband, it can transmit sth like ten times as much in a given time LAN is one of the distributed processing designs - LAN are considered loosely coupled system processors are located in separate machines and communicate at relatively low speeds - LAN is the means by which distribution takes places, regardless of what are distributed Chapter 10: DATA COMMUNICATIONS. Question 1. Write a short note of? 1. Communication is an extensive subject in its own right, encompassing not only data transmission but also sound and video transmission via telephone lines, radio links and satellite links. 2. Multiplexing is a means of combining together data from several sources so that it can be transmitted along one comminication line 3. Front – end processing: A front – end processor is usually a minicomputer or a microcomputer interposed between the main computer and the multiplexor Its purpose is to relieve the host computer from the bunden of communications housekeeping 4. Concentrators are device used to gather the bit from each terminal or group of terminal and hold them on buffer store unit until there are sufficient to justify forward transmission 5. Protocol is an “agreement” where by devices can communicate is a fully understand manner 6. Multidrop line<multipoint line> has several terminals on concentrator attached to it 7. Distributed data processing sys is one of which interconnected points at which processing power and storage capacity are availble Question 2. Fibre Optics? Fibre optics is that data and other information is transmitted in the form of light through very fine glass fibres Ads: - High bandwidth eg data transmission capacity - Low cross – talk eg interference between adjacent fibres - Low attenuation eg loss of signal strength - Freedom from interference from external electrical and electromagnetic equipment - High reliability - Safe because no heat, sparks or electrical voltages are created - Economic because glass is loss expensive than copper Chapter 11: DISTRIBUTED PROCESSING. Question 1. Client/ Server Model? - It’s common way to employ distributed processing that is client/server architecture which splits into components - Server store & main palates the actual data & provide secenity, losting function transaction logging recovery capabilities - Client/ server model seems like PC lan each server support more users - Data request in form of SQL(structure quenf language) command travel across the network from client to server Client Server Database Request LAN Response Question 2. File sharing VS client server? Network Client Server The file sharing model << Continuousting to page 28>> Network Interface Interface The client/ server model File sharing - File are shared for a lot of machines in the network(each Client server - Database are stored in the server machines and client Application tool process Application tool process Database Application tool process Database engine process Database Database engine process SQL execute commands machine can access to the shared files) - It can create heavy network traffic(each access to a large file can potentially block of the file, showing the system amount of information temporarily unavailable to other user) machines can send request for appropriate data - Only the records matching the request criteria raresent back to client machines so the sys never has heavy traffic Question 3. Distributed Database Topology? - With distributed processing system, user can access data, that is located among a number of physically separate servers. It provides user with a globol view of the data. - With distributed database, the problems with implementing still exists. - Developing distributed database application requires extensive planning to anticipate the many complex possibilities. - For a large number of transactions travelling across the network the capacity of communication lines and the possible impact a system must be carefully considered. Chapter 12: THE TCP/IP PROTOCOL SUITE. Question 1. The OSI model? <Open System Interconnection> - OSI model, adopted in 1983 by IOS <International Organization Standardization>, which is a framework for defining standards for linking hetenogenerous computer - The communication function are pastitioned into a vertical set of layers. Each layer performs are lated subset of the functions required to communicate with other sys - The OSI layers Physical: concerned with transmission of unstructured bit stream over physical medium, deals with the mechinical, electrical, functional, and procedual characteristrics to access the physical medium Data link: provides for the reliable transfer of information across the physical link, send blocks of data with the necessary synchronization, error control, and flow control. Network: provides upper layers with independence from the data transmission and switching technologies used to connect systems, responsible for establishing, maintaining and terminating connections Transport: provides rediable, transparent transfer of data between end points, provide end_to_end error recovery and flow control. Session: provides the control structure for communicaton between applications, establishes, manages, and terminates connections between cooperating applications. Presentation: provide independence to the application processes from difference in data representation(syntax) Application: provide access to the OSI environment for users and also propvides distributed information services User oriented Application Users of transport Presentation service End to end Session connection oriented Transport Network Point to point Data link Network service link oriented Physical Perspectives on the OSI architecture Question 2. Protocols? Both OSI and the TCP/IP protocol suite deal with communications among hetrnogenerous computers Both are based on the concept of protocol and have many similarities a. TCP/IP protocol architecture TCP: Transmission Control Protocol IP: Internet Protocol - The TCP/IP protocol architecture is based on a view of communication that involves three agents: processes, hosts, and networks - Communication between processes takes place across networks to which the hosts are attached - A network need only be concerned with routing data between hosts, as long as the hosts agree how to direct data to processes - It is natural to organize protocols into four layer i. Network access layer: contains those protocols that provide access to a communication network ii. Internet layer consists of the procedures required to allow data to traverse multiple networks between hosts iii. Host_host layer: containts protocol entities with the ability to deliver data between two processes on different host computers iv. Process/ application layer: contains protocols for resource sharing and remote access b. Operation of TCP/IP Application Application TCP TCP OS IP OS IP Network access protocol 1 Network access protocol 2 Network 1 Network 2 Netwo Communications using the TCP/ IP protocol architecture NAP: Network Access Points - IP is implemented in all of the end systems it keeps track of blocks of data to ansure that all are dilivered veliably to the appropriate application - For successful communication, every entity in the over all sys must have a unique address, two level of addressing are needed Global Internet Address(for communication) Ports(for service) Try your best, you will get the best! Contents BOOK I: Computer system fundamentals. CHAPTER 1 INTRODUCTION TO COMPUTER 2 CHAPTER 2 MICROPROCESSOR 3 CHAPTER 3 BATCH/ ONLINE AND REAL TIME PROCESSING SYSTEM . 4 IP NAP 1 NAP2 . Model? - It s common way to employ distributed processing that is client/server architecture which splits into components - Server store & main palates the actual data & provide secenity,. of physically separate servers. It provides user with a globol view of the data. - With distributed database, the problems with implementing still exists. - Developing distributed database. is transmitted in the form of light through very fine glass fibres Ads: - High bandwidth eg data transmission capacity - Low cross – talk eg interference between adjacent fibres - Low attenuation