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Experiment-3

Aim :- Introduction to Client-Server Architecture, Peer- to- Peer Networking, Hybrid

Networking, Direct Cable Connection.

Client-Server Architecture:The client-server software architecture model distinguishes client systems from server

systems, which communicate over a computer network. A client-server application is a

distributed system comprising both client and server software.

A client software process may initiate a communication session, while the server waits for

requests from any client.

Client-server describes the relationship between two computer programs in which one

program, the client program, makes a service request to another, the server program.

Standard networked functions such as email exchange, web access and databaseaccess, are based on the client-server model. For example, a web browser is a client

program at the user computer that may access information at any web server in the world.

The client-server model has become one of the central ideas of network computing. Most

business applications being written today use the client-server model. So do the Internet's

main application protocols, such as HTTP, SMTP, Telnet, DNS, etc. In marketing, the

term has been used to

distinguish distributed computing

by smaller dispersed computers

from the "monolithic" centralizedcomputing of mainframe

computers. But this distinction

has largely disappeared as

mainframes and their

applications have also turned to

the client-server model and

become part of network

computing.

Each instance of the client

software can send data requests

to one or more connected

servers. In turn, the servers can

accept these requests, process them, and return the requested information to the client.

Although this concept can be applied for a variety of reasons to many different kinds of

applications, the architecture remains fundamentally the same.

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The most basic type of client-server architecture employs only two types of hosts: clients

and servers. This type of architecture is sometimes referred to as two-tier. It allows

devices to share files and resources. The two tier architecture means that the client acts

as one tier and application in combination with server acts as another tier.

When both the client- and server-software are running on the same computer, this is

called a single seat setup.

Specific types of clients include web browsers, email clients, and online chat clients.

Specific types of servers include web servers, ftp servers, application servers, database

servers, mail servers, file servers, print servers, and terminal servers. Most web services

are also types of servers.

Peer-to-Peer Networking:A peer-to-peer (or P2P) computer network uses diverse connectivity between participantsin a network and the cumulative band widthof network participants rather than

conventional centralized resources where a relatively low number of server provide the

core value to a service or application.

P2P networks are typically used for connecting nodes via largely ad hoc connections.

Such networks are useful for many purposes. Sharing content files containing audio,

video, data or anything in digital format is very common, and real time data, such as

telephony traffic, is also passed using P2P technology.

A type of network architecture is known as peer-to-peer, because each host or instance of

the program can simultaneously act as both a client and a server, and because each has

equivalent responsibilities and status. Peer-to-peer architectures are often abbreviated

using the acronym P2P.

Both client-server and P2P architectures are in wide usage today. You can find more

details in Comparison of Centralized (Client-Server) and Decentralized (Peer-to-Peer).

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A pure P2P network does not have the notion of clients or servers but only equal peer

nodes that simultaneously function as both "clients" and "servers" to the other nodes on

the network. This model of network arrangement differs from the client-server model

where communication is usually to and from a central server. A typical example of a file

transfer that is not P2P is an FTP server where the client and server programs are quite

distinct: the clients initiate

the download/uploads,

and the servers react to

and satisfy these

requests.

However, the news server

system acted in a client-

server form when

individual users accessed

a local news server toread and post articles.

The same consideration

applies to SMTP email in

the sense that the core

email relaying network of Mail transfer agents follows a P2P model while the periphery of

e-mail clients and their direct connections is client-server.

ADVANTAGES:

Peer-to-peer networking has the following advantages over client/server networking:

Content and resources can be shared from both the center and the edge of the

network. In client/server networking, content and resources are typically shared

from only the center of the network.

A network of peers is easily scaled and more reliable than a single server. A single

server is subject to a single point of failure or can be a bottleneck in times of high

network utilization.

A network of peers can share its processor, consolidating computing resources for

distributed computing tasks, rather than relying on a single computer, such as a

supercomputer.

Shared resources of peer computers can be directly accessed. Rather thansharing a file stored on a central server, a peer can share the file directly from its

local storage.

Peer-to-peer networking solves the following problems:

Allows the processing resources of edge computers to be utilized for distributed

computing tasks.

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Allows local resources to be shared directly, without the need for intermediate

servers.

Allows efficient multipoint communication without having to rely on IP multicast

infrastructure.

Hybrid Networking:

A hybrid network is a local area network (LAN) containing a mix of both wired and

wireless client devices. In home networks, wired computers and other devices generally

connect

with Ethernet cables,

while wireless devices

normally use Wi-

Fi technology.

It refers to any computer

network that contains two

or more different

communications

standards. In this case,

the hybrid network uses

both Ethernet (802.3) and

Wi-Fi (802.11 a/b/g)

standards. A hybrid

network relies on special hybrid routers, hubs and switches to connect both wired and

wireless computers and other network-enabled devices.

Direct Cable Connection:

A direct cable connection is a link between the input/output (I/O) ports of two computers

by using a single cable rather than a modem or other interfacing device. Direct Cable

Connection (DCC), is a feature that allows a computer to transfer and share files (or

connected printers) with another computer, via a connection using either the serial

port, parallel port or the infrared port of each computer.