Distributed Processing and Network Criteria, Slides of Network Theory

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Networks

By DrYasir Afaq

Distributed Processing

• (^) A Distributed System is a Network of Machines that can exchange

information with each other through Message-passing.

• (^) It can be very useful as it helps in resource sharing.
• (^) It enables computers to coordinate their activities and to share the

resources of the system so that users perceive the system as a

single, integrated computing facility.

Client/Server Systems

• (^) Client/Server Systems: Client-Server System

is the most basic communication method where

the client sends input to the server and the

server replies to the client with an output.

• (^) The client requests the server for resources or a

task to do, the server allocates the resource or

performs the task and sends the result in the

form of a response to the request of the client.

• (^) Client Server System can be applied with

multiple servers.

Peer-to-Peer Systems

• (^) Peer-to-Peer Systems: Peer-to-Peer System

communication model works as a decentralized model

in which the system works like both Client and Server.

• (^) Nodes are an important part of a system.
• (^) In this, each node performs its task on its local memory

and shares data through the supporting medium, this

node can work as a server or as a client for a system.

• (^) Programs in the peer-to-peer system can communicate

at the same level without any hierarchy.

Three-tier

• (^) Three-tier: Three-tier system uses a separate layer and server

for each function of a program.

• (^) In this data of the client is stored in the middle tier rather than

sorted into the client system or on their server through which

development can be done easily.

• (^) It includes an Application Layer, Data Layer, and Presentation

Layer. This is mostly used in web or online applications.

N-tier:

• (^) N-tier: N-tier is also called a multitier

distributed system. The N-tier system can

contain any number of functions in the

network.

• (^) N-tier systems contain similar structures to

three-tier architecture.

• (^) When interoperability sends the request to

another application to perform a task or to

provide a service. N-tier is commonly used in

web applications and data systems.

Network Criteria

• (^) A Network is a group of connected devices capable of

communicating. The device can be a computer, printer, or

scanner that either receives or transmits data. The devices

connected in the Network are called "Nodes," and the means of

connection can be wired or wireless.

• (^) There are a lot of criteria that make a network better than others,

but; there are three basic yet important criteria to be fulfilled for

a network:

1.Performance

2.Reliability

3.Security

Performance

It measures how well a network can support communication between two nodes

in the Network or with nodes of other networks in the global scope.

The two major tasks in a network are the Transmission and reception of

information.

We need to focus on how fast a message is transmitted and how fast a node can

receive a request and find the needed information. Hence, to measure the

performance of a network, here are the major factors to be considered:

Reliability

It is the degree to which a network is trustworthy, consistent ,

and dependable.

The Reliability of a network is measured by the frequency of failures it

is undergoing and the time it takes to recover from the failures.

Overall, the Robustness of the Network at times of catastrophic events

is measured to check how reliable the Network is.

Security

• (^) It measures how the Network secures the data amid

failures and attacks and the policies and procedures it

implements to protect itself from damages and

unauthorized access.

• (^) In Reliability, the frequency of failures is checked. In

Security, network attacks and data breaches are

checked.