Module 3 - Data Communications
Data Communication Network - ANS-A combination of software, hardware and media designed
for the transmission of data from one entity to another.
Common Networks - ANS-• telephone (landline);
• cell phone (wireless);
• home;
• school/workplace;
• corporate (span world);
• military;
• Internet;
• modern cars
Basic Functions of Applications - ANS-• 1) data storage (basic operating system file
management functions);
• 2) data access (database storage and retrieval functions);
• 3) application logic (specific application-dependent logic);
• presentation logic (graphical user interface logic)
Host-Based Architecture - ANS-Put all the processing on a single computer and provide a very
simple text-based interface to a dumb terminal.
Time-Sharing Operating Sytems - ANS-Allowed many users, each with their own dumb terminal
to "use" one machine simultaneously, when in reality it switched between users very fast.
Sensor-backed Applications - ANS-Very tiny hosts collect limited amounts of information that is
then communicated to the server for processing (could be considered host-based application
architecture).
Advancements in the 70's and 80's - ANS-• 1) Silicon densities became great enough to make
microprocessors and low-cost microcomputers feasible;
• 2) Relatively inexpensive networks, such as Ethernet-based local area networks and network
operating systems such as Novell, were developed;
• 3) Commercial off the shelf software (COTS) became available to address common processing
needs of many organizations.
Client-Based Architecture - ANS-Restructured applications to take advantage of the increased
processing power of microcomputers, the network to transfer files, and a server to perform the
data storage function.
, Client-Server Architectures - ANS-Developed to move more of the processing like data access
logic to the server to reduce the load on both the client machine and the network. Clients make
requests and servers respond. Ex: web with web browser as client and web server as server
Client/Server Applications - ANS-• email clients;
• file transfer clients;
• terminal emulation clients
Four-Tier Architecture Layers - ANS-• 1) client running browser;
• 2) web server;
• 3) application server (one or more);
• 4) database server
Peer-to-Peer Application - ANS-Allows a single machine to serve the functions of both client and
server and connects many of these dual-purpose machines together via a network. Useful for
sharing files. Application system relies on computing power of participants and bandwidth of the
network.
Cloud Computing - ANS-• uses n-tier architecture;
• facilities offer services to users and businesses;
• can potentially offer services in more cost effective manner;
• facilities dynamically reallocate resources across different customers;
• customers pay for usage on shared infrastructure;
• hosted services can include software, platform, infrastructure and hardware;
Challenges of Cloud Computing Services - ANS-• less control or visibility than using own
infrastructure;
• control over reliability;
• control over security;
• control over availability of services and data;
• control over service;
• cost;
• customization;
• privacy
Components of a Network - ANS-• Applications;
• Messages;
• Protocols;
• Sending (Originating) Devices;
• Communications Channels;
• Communications Devices;
• Receiving (Destination) Devices
Data Communication Network - ANS-A combination of software, hardware and media designed
for the transmission of data from one entity to another.
Common Networks - ANS-• telephone (landline);
• cell phone (wireless);
• home;
• school/workplace;
• corporate (span world);
• military;
• Internet;
• modern cars
Basic Functions of Applications - ANS-• 1) data storage (basic operating system file
management functions);
• 2) data access (database storage and retrieval functions);
• 3) application logic (specific application-dependent logic);
• presentation logic (graphical user interface logic)
Host-Based Architecture - ANS-Put all the processing on a single computer and provide a very
simple text-based interface to a dumb terminal.
Time-Sharing Operating Sytems - ANS-Allowed many users, each with their own dumb terminal
to "use" one machine simultaneously, when in reality it switched between users very fast.
Sensor-backed Applications - ANS-Very tiny hosts collect limited amounts of information that is
then communicated to the server for processing (could be considered host-based application
architecture).
Advancements in the 70's and 80's - ANS-• 1) Silicon densities became great enough to make
microprocessors and low-cost microcomputers feasible;
• 2) Relatively inexpensive networks, such as Ethernet-based local area networks and network
operating systems such as Novell, were developed;
• 3) Commercial off the shelf software (COTS) became available to address common processing
needs of many organizations.
Client-Based Architecture - ANS-Restructured applications to take advantage of the increased
processing power of microcomputers, the network to transfer files, and a server to perform the
data storage function.
, Client-Server Architectures - ANS-Developed to move more of the processing like data access
logic to the server to reduce the load on both the client machine and the network. Clients make
requests and servers respond. Ex: web with web browser as client and web server as server
Client/Server Applications - ANS-• email clients;
• file transfer clients;
• terminal emulation clients
Four-Tier Architecture Layers - ANS-• 1) client running browser;
• 2) web server;
• 3) application server (one or more);
• 4) database server
Peer-to-Peer Application - ANS-Allows a single machine to serve the functions of both client and
server and connects many of these dual-purpose machines together via a network. Useful for
sharing files. Application system relies on computing power of participants and bandwidth of the
network.
Cloud Computing - ANS-• uses n-tier architecture;
• facilities offer services to users and businesses;
• can potentially offer services in more cost effective manner;
• facilities dynamically reallocate resources across different customers;
• customers pay for usage on shared infrastructure;
• hosted services can include software, platform, infrastructure and hardware;
Challenges of Cloud Computing Services - ANS-• less control or visibility than using own
infrastructure;
• control over reliability;
• control over security;
• control over availability of services and data;
• control over service;
• cost;
• customization;
• privacy
Components of a Network - ANS-• Applications;
• Messages;
• Protocols;
• Sending (Originating) Devices;
• Communications Channels;
• Communications Devices;
• Receiving (Destination) Devices
