L7- Building Telecommunication System (Part 3) Flashcards
An important current development in organizational computing is ____________ - moving from platforms based on mainframes and minicomputers to a microcomputing environment. These architectures are
based on the client/server model.
downsizing
Most frequently used models of client/server computing are:
- Two-Tier Architecture
- Three-Tier Architecture
TRUE OR FALSE:
In client/server computing, individual applications are actually written to run on several computer platforms to take advantage of their capabilities.
True
TRUE OR FALSE:
2. Main objective of a client is to provide a graphical user interface to a user
3. Main objective of a server is to provide shared services to clients
True
Characteristics of Two-Tier Architecture:
- Client performs presentation services. It displays the GUI and runs the program that determines what happens when the user selects a menu option.
- Server manages the accesses to
the database - Clients send remote procedure calls to activate specific applications logic on a server.
Characteristics of Three-Tier Architecture:
An application server runs most of the application logic, with the user workstation responsible for the display at the front end and the database server providing database servers at the back end. Objective is to distribute application so as to reduce the overall hardware costs while minimizing the network traffic.
Issues of client/server computing:
- Is attractive in terms of their acquisition price as related to their performance
- Is moving computing control out of the data centers and into the end-user areas
- Software is complex, and is expensive to maintain
- Generate significant traffic on the firm’s backbone network that connects clients and servers
- Can be performed in LAN and WAN environments
_________________are the fundamental infrastructure of organizational computing. These long-distance telecommunications networks employ a variety of equipment so that the expensive links may be used effectively.
Wide Area Networks
A WAN has a powerful ______________. The host runs a system program, called a telecommunications monitor, which processes incoming messages, passing them to the appropriate application programs, and accepts outgoing messages from the applications in order to transmit them into the network.
Host Computer
Relieves the host computer of most of the
tasks involved in network control. Under
the control of its own software, the _____________ accepts messages coming from the network and routes outgoing messages to their destinations.
Front-end Processor
- It performs the necessary code conversions, encrypts and decrypts secure messages, and performs error checking so that the host deals with Aclean@ messages
Manages several terminals, connecting them to a single telecommunications link, and performs communication tasks for them, such as screen formatting, code conversion, and error checking.
Cluster Controller
-may also allow the terminals to share a high-speed printer and may handle electronic mail among
the cluster terminals.
Combines the data that terminals send to it over local low-speed links into a single stream. This stream is then transmitted over a high-speed telecommunications channel and is split by another on the opposite end of the channel
Multiplexor
Combines transmission from several slower terminals that operate in a burst mode into a single transmission stream that requires a link of lower speed than the sum of the speeds of all the terminals combined.
Concentrator
-stores messages from terminals and forwards them when warranted.
Establishes connections between nodes that need to communicate.
Switches
Include a variety of dumb terminals, with no processing capacity and intelligent terminals with processing capacity, such as personal computers.
Access Terminals