CHAPTER 1 INTRODUCTION TO COMPUTER NETWORKS Networking Basic

Summary

This script delves into the classification of computer networks, focusing on three main criteria: host roles, geographic proximity, and signaling methods. It distinguishes between peer-to-peer networks, where hosts share and consume resources equally, and client-server networks, where designated servers provide resources to client computers. The script also covers local area networks (LANs) confined to small areas and wide area networks (WANs) that span larger, geographically dispersed regions. Lastly, it explains baseband and broadband signaling, highlighting their capacity for single or multiple simultaneous signals on a network medium.

Takeaways

• 📚 The script discusses three main ways to categorize computer networks: by host roles, geographic proximity, and signaling methods.
• 💻 In a peer-to-peer network, hosts both provide and consume network services, functioning as both clients and servers.
• 🚀 Peer-to-peer networks are easy to implement and inexpensive, but they lack centralized control and are not scalable.
• 🔒 A key issue with peer-to-peer networks is the lack of centralized file storage, leading to potential data loss and difficulty in backup.
• 🖥️ Client-server networks assign specific roles to hosts, with servers providing resources and clients consuming them.
• 📈 Client-server networks are highly scalable and easier to support due to centralized services and resources.
• 🛠️ The downside of client-server networks is the higher cost of specialized server operating systems and the need for extensive planning.
• 🌐 Geographically, networks can be classified as local area networks (LANs), which are confined to a small area, or wide area networks (WANs), which connect networks over a larger geographic area.
• 🏢 LANs can be within a single building or span multiple buildings, while WANs can connect different LANs across cities or countries.
• 🌐 In a WAN, resources are typically located locally to minimize the need for data to travel long distances, improving efficiency.
• 📡 The script also explains two types of signaling: baseband, which allows only one signal at a time on the network medium, and broadband, which can transmit multiple signals simultaneously.
• 📺 An example of broadband signaling is cable TV, where multiple channels use the same cable concurrently, while baseband signaling is exemplified by traditional telephone lines, which can only handle one call at a time.

Q & A

What are the three classifications mentioned for categorizing computer networks?

The three classifications mentioned for categorizing computer networks are host roles, geographic proximity, and signaling methods used.

What is a peer-to-peer network and how do hosts function in it?

A peer-to-peer network is a type of network where each host can both provide and consume network services. Hosts in a peer-to-peer network do not have a specific role; they can share resources like printers or storage and also use those shared resources from other hosts.

Why are peer-to-peer networks considered easy to implement?

Peer-to-peer networks are considered easy to implement because they require minimal configuration. Users simply share their resources, and there is no need for special software or complex setup.

What are some drawbacks of peer-to-peer networks?

Some drawbacks of peer-to-peer networks include a lack of scalability, difficulty in management due to the absence of centralized control, and issues with data backup and file storage since files can be scattered across various hosts.

What is the difference between a client and a server in a client-server network?

In a client-server network, a server is a host that provides network resources, while a client is a host that consumes those resources. Clients do not provide services; they only use the services provided by the server.

Why are client-server networks considered more scalable than peer-to-peer networks?

Client-server networks are considered more scalable because they allow for easy expansion of the network size. Adding more clients or servers is straightforward, and services are centralized, making management and support easier.

What is a local area network (LAN) and how is it defined geographically?

A local area network (LAN) is a computer network that covers a small geographic area, such as a single building or a group of buildings within close proximity. It is defined by the relatively small geographic separation between network hosts.

What is a wide area network (WAN) and how does it differ from a LAN?

A wide area network (WAN) is a group of interconnected LANs that are geographically dispersed over a larger area, such as different cities or regions. It differs from a LAN in terms of the geographic distribution of its hosts and networks.

What is the purpose of connecting local area networks to form a wide area network?

The purpose of connecting local area networks to form a WAN is to allow users in different locations to access and share information across various sites, facilitating communication and resource sharing over a larger geographic area.

What are the two types of signaling used in networks and how do they differ?

The two types of signaling used in networks are baseband and broadband signaling. Baseband signaling allows one signal at a time to use the entire network medium, while broadband signaling divides the network medium into multiple channels, enabling multiple signals to be transmitted simultaneously.

Can you provide an example of a network using broadband signaling?

An example of a network using broadband signaling is a cable TV system, where multiple channels (e.g., channel 2, 4, 5, 6, 7) use the same cable simultaneously, transmitting different signals at the same time.

Outlines

00:00

🔗 Peer-to-Peer and Client-Server Networks

The script begins by discussing the classification of computer networks based on host roles, focusing on two main types: peer-to-peer and client-server. In a peer-to-peer network, hosts both provide and consume network services, exemplified by shared resources like printers and storage. This type of network is easy to implement and inexpensive, but it is not scalable and lacks centralized control, leading to potential issues with resource management and data backup. On the other hand, a client-server network assigns specific roles to network hosts, with servers providing resources and clients consuming them. This setup is more scalable, easier to support, and simplifies backup processes, but it requires more planning and investment in specialized server operating systems.

05:03

🌐 Geographic Classification of Networks: LANs and WANs

The second paragraph delves into the geographic classification of computer networks, distinguishing between local area networks (LANs) and wide area networks (WANs). LANs are confined to a small geographic area, such as a single office building or multiple interconnected buildings within a campus. They are designed to connect systems within close proximity, facilitating internal communication and resource sharing. In contrast, WANs consist of interconnected LANs spread across larger geographical distances, allowing for communication and data access between remote locations. The script uses the example of XYZ Corp, which has offices in different cities, to illustrate how a WAN enables access to shared resources across its various locations.

10:04

📡 Signaling Methods: Baseband and Broadband

The final paragraph addresses the classification of computer networks based on the signaling methods they use. Baseband signaling allows for only one signal at a time to occupy the entire network medium, which is suitable for traditional telephone systems where simultaneous connections are not possible. In contrast, broadband signaling divides the network medium into multiple channels, enabling the transmission of multiple signals simultaneously. This method is akin to cable TV systems, where numerous channels can be broadcasted over a single cable. The script highlights the benefits of broadband signaling in terms of increased capacity and the ability to support various services concurrently.

Keywords

💡Computer Networks

Computer networks are interconnected systems of computing devices that share data and resources. In the video, the theme revolves around understanding different classifications of computer networks, which is essential for grasping the various ways they can be structured and function.

💡Host Roles

Host roles refer to the specific functions that devices (hosts) perform within a network. The script discusses two primary host role classifications: peer-to-peer and client-server. These roles are central to understanding network architecture and how resources are shared and managed.

💡Peer-to-Peer Network

A peer-to-peer network is a distributed network where each node (host) can act as both a client and a server, sharing resources like storage and printers. The script explains the ease of implementation and the challenges of scalability and management in such networks.

💡Geographic Proximity

Geographic proximity is a classification criterion based on the physical location of the network's components. The video script describes local area networks (LANs) as having a small geographic area, while wide area networks (WANs) span larger, sometimes nationwide or global, distances.

💡Signaling Methods

Signaling methods refer to the techniques used for data transmission on a network. The script distinguishes between baseband and broadband signaling, explaining how they affect the capacity and efficiency of the network medium.

💡Local Area Network (LAN)

A local area network is a computer network that spans a small geographic area, such as a single building or campus. The script uses LANs to illustrate networks that are interconnected within a limited physical space, forming an internetwork.

💡Wide Area Network (WAN)

A wide area network connects multiple local area networks over a larger, often geographically dispersed, area. The script explains that WANs enable access to resources across different sites, such as offices in various cities.

💡Client-Server Network

A client-server network is a model where servers provide resources and services to clients, which consume these resources. The script highlights the scalability and support advantages of client-server networks compared to peer-to-peer networks.

💡Scalability

Scalability refers to the ability of a network to expand and accommodate growth. The script points out that client-server networks are highly scalable, making it easier to add more clients or servers as needed.

💡Centralized Control

Centralized control in a network implies a single point of administration for managing resources and services. The script contrasts the lack of centralized control in peer-to-peer networks with the centralized management in client-server networks, affecting support and resource allocation.

💡Baseband Signaling

Baseband signaling is a method where only one signal can occupy the network medium at a time. The script uses the analogy of a traditional telephone system to illustrate how baseband signaling limits simultaneous usage of the network medium.

💡Broadband Signaling

Broadband signaling allows multiple signals to be transmitted simultaneously over the same network medium through different channels. The script provides the example of cable TV, where multiple channels can be viewed at the same time, to explain broadband signaling.

Highlights

Introduction to three classifications of computer networks: host roles, geographic proximity, and signaling methods.

Explanation of peer-to-peer networks where hosts both provide and consume network services.

Advantages of peer-to-peer networks, including ease of implementation and low cost.

Drawbacks of peer-to-peer networks, such as lack of scalability and centralized control.

Risks associated with decentralized management in peer-to-peer networks, like accidental data deletion.

Challenges in backing up data in peer-to-peer networks due to the dispersed storage locations.

Introduction to client-server networks with specific roles for network hosts.

Definition and role of servers in providing network resources in client-server networks.

Client role in client-server networks as consumers of network services.

Differences in operating systems used for clients and servers in client-server networks.

Benefits of client-server networks, such as scalability, ease of support, and centralized services.

Cost implications of client-server networks, including the expense of server operating systems.

Importance of planning in setting up client-server networks compared to peer-to-peer networks.

Geographic classification of computer networks into local area networks (LANs).

Description of wide area networks (WANs) as interconnected LANs over a larger geographic area.

The concept of an internetwork connecting multiple LANs within a WAN.

Strategies for resource allocation in WANs to ensure local access for users.

Introduction to the types of signaling in networks: baseband and broadband.

Comparison between baseband and broadband signaling in terms of signal transmission capabilities.

Examples of broadband signaling in cable TV systems and the evolution of telephone systems.

Transcripts

let's talk about the different ways we

can categorize computer networks there's

actually a variety of different

classifications we can use here we're

going to talk about three of them we're

going to talk about host roles we're

going to talk about geographic proximity

and then the signaling methods used

let's first talk about classifying

networks according to the host roles in

other words what do the hosts do in the

network the first one we want to look at

is called peer-to-peer in a peer-to-peer

network network hosts don't have a

specific role that they play in other

words hosts on a peer-to-peer network

both provide

network services and hosts on a

peer-to-peer network also consume

network services

what exactly does that mean well in a

peer-to-peer network we have a variety

of operating systems here and they

fulfill a variety of different roles for

instance over here we may have a

workstation that has a printer connected

to it and that printer is shared on the

network allowing each of these different

hosts to print to that printer over here

this host might have a huge hard drive

installed

and everyone is allowed to share that

hard drive if they have a huge file they

need to save they can put this file down

here well in this situation you have

hosts that both provide and consume

network services these two hosts provide

a network service this one provides

printing this one provides storage now

at the same time these hosts also

consume services for instance this hosts

prints to this workstation this

workstation saves files to the hard

drive in this workstation in essence

they function both as a client and as a

server at the same time now there's a

lot of benefits to appear to peer

network first of all it's very easy to

implement in other words you could take

a whole bunch of Windows XP workstations

for example and create a peer-to-peer

network you can share printers share

storage you don't have to go to any

trouble to configure this all you have

to do is share your resources it's very

easy to implement it's also very

inexpensive in this case with a Windows

XP II peer-to-peer network you just

install the operating system that's it

there's no special software to purchase

and implement now there's some drawbacks

to a peer-to-peer network you might be

asking well it's so easy to implement so

inexpensive why don't more companies

implement it well there are some key

problems first of all a peer-to-peer

network is not very scalable meaning the

bigger it gets the harder it is to

manage and the harder it is to keep

running

peer-to-peer networks are very very

difficult to support that's because they

lack centralized control in other words

there's not one network administrator

kind of running the show every user at

each workstation is kinda like their own

little network administrator let's take

an example of how this is a problem

let's say that you have shared storage

over here on this hard drive and this

workstation belongs to Fred Fred says

well you know there's get to be lawful a

lot of files on my hard drive I think

I'm gonna erase a whole bunch of them

let's just erase him so I have more room

on my hard disk what impact does that

have on everybody else well Mary over

here might have had her files on that

hard drive and he just wiped him out and

she's going ah my files ok no

centralized control further let's

suppose Mary decides to get back at

everybody because Fred over here deleted

her files and she takes off the next day

from work these are off a store locked

in a computer off everybody needs to

print can they print nope they can't

this host is down you can access its

printer

another problem is the fact that when

you have a peer-to-peer network there's

no real centralized place to save files

we could have storage on this system we

could have maybe some other shared

storage on this system maybe some other

shared storage on this system maybe even

some over here on this system

when it comes time to back up and

protect critical company data you've got

to go to each one of these hosts and

backup their data you may not know

exactly where folks are saving it it can

be all over the place on the hard drives

now we have another classification

within the hosts roles category and that

is a client server network and a client

server network unlike a peer-to-peer

network network hosts have specific

roles assigned to them in the client

server network you have certain systems

certain hosts that are assigned to be

servers

what is a server do a server provides

network resources

you

you also on a client-server network have

clients

now a client does not provide network

services it consumes

work services

what does that mean that means in a

client

server network these client workstations

will not have shared storage they will

not have shared printers all those

services are provided down here by the

server may have a humongous

our drive maybe we have a printer that

this server manages

cetera server provides the resources the

client simply use the resources now to

do that we have different operating

systems implemented recall with a

peer-to-peer network everybody have the

same operating system not so in a

client-server Network

giant workstations have generic

operating systems that provide

functionality such as being able to run

applications 2d word processing

spreadsheets etc and software that

allows them to connect to the server

examples would be Windows XP maybe

Windows 2000 professional those are

client workstation operating systems a

server on the other hand has special

optimized operating systems and these

operating systems aren't designed for

client type tasks such as we're

processing spreadsheets although some of

them will do it that's not their main

job for example server operating systems

include NetWare

Linux

windows

mm and server

2003 these operating systems are

designed to provide these network

resources now the benefits of this type

of network is first of all that it's

very highly scalable

what does that mean that means it's very

easy to expand the size of the network

it's very easy to add more clients it's

very easy to add more servers

client-server networks are also much

easier to support that's because

services are centralized if folks are

having problem accessing their files

well you know where to look it's on the

server ok and you check out the storage

on the server if folks are having

trouble printing you know where to look

because the service is provided by the

server backup is also a lot easier

instead of having to backup individual

workstations they're saving their data

over here in the storage system on the

server itself now you're still using

your relatively inexpensive client

operating systems up here just like with

a peer-to-peer network such as Windows

XP Windows 2000 professional the expense

comes down here these operating systems

for the most part are relatively

expensive the exception of course is

Linux net where it's relatively

expensive when those 2000 server is very

expensive Server 2003 is relatively

expensive as well the other thing is

that this type of network takes a lot of

planning beforehand now if I'm a

peer-to-peer network you kind of just

slap things together you set up your

systems and the way you go you don't do

that with a client-server network you

pre-plan everything you decide which

servers are going to host which services

and you decide where they're going to be

placed on the network etc well that's

how we categorize computer networks by

host role now let's look at a different

way of categorizing computer networks

and that is geography the first category

is that of a local area network now a

local area network resides within a

small geographic area an example of a

local area network would be in the

network inside a particular company's

office it has multiple floors but these

are all connected

by a network medium in some way this

comprises a local area network it could

be multiple buildings in fact you'd have

a second building over here

several floors

computer systems

and these are all interconnected

in some fashion it's still a local area

network because the geography separating

the host is relatively small you could

even have other buildings and over here

with their own networks

for instance perhaps a college campus

there's a building here and a building

here and then you connect all the

networks together

when you do that by the way that's

called an internetwork

however this is still a land because

they're geographically

close together now it's also possible to

have a computer network where the

networks and the hosts are very widely

distributed geographically when we have

that situation we're talking about a

wide area network basically a wide area

network is a group of interconnected

LANs local area networks that are

separated geographically for example

suppose we have a company named XYZ Corp

XYZ

us over here in New York City they have

a local area network

company also has an office down here in

Houston Texas and then they also have an

office up here in Portland Oregon now

users in these different locations

occasionally need to have access to

information at these various different

sites to make that possible we've

connected them

in some way

these local area networks are

internetwork together making a very

large internet work or a wide area

network now when you set up a win

basically the way it's done is that you

make sure that the resources that the

users need are located on the local land

for example if someone needs to open a

file here in New York City you don't

want them to have to go clear down here

transverse the wide area network to

Houston open up a file and bring it back

here and work on it over here in New

York City then when you save you have to

go clear across the country again just

to save on a server located down here

instead you'll locate the information

and resources that each local area

network needs here locally so you set up

a server here in New York City with the

information that the users here in New

York City would need

likewise you wouldn't want to store your

user accounts over here in Portland so

that someone who needs to log into the

network down here in Houston has to go

across the land link Claire over here to

Portland just to authenticate the

benefit of the win is that if the

situation arises say a user here needs

access to a document that's being worked

up bond by a product team over here in

Portland they can use the wide area

network to get that information and open

it over here so those are the two

different classifications or

categorizing networks by their size and

there are geographic proximity there's

one more categorization I want to talk

about here and that is the type of

signaling used by the network there's

basically two types there's baseband

signaling and then there's broadband

signaling this right here represents our

network medium whether it's a wire or

whether it's a piece of fiber-optic

cable or what have you

with baseband signaling you can have one

signal at a time on the network medium

and that signal uses the entire network

medium all at the same time broadband

signaling on the other hand divides the

network medium into multiple channels

with broadband signaling you can have

multiple signals all being transmitted

on the same network medium at exactly

the same time

on a good example of broadband signaling

think of your cable TV system if you

have cable TV

you have channel 2 4 5 6 7 etc you have

multiple signals all using the same

cable at the same time baseband

signaling in the old days I used to use

the example of a telephone now telephone

systems are starting to use broadband

signaling to allow you to have DSL and

your telephone conversations at the same

time but in the old days telephones used

to use baseband signaling in other words

you picked up the phone receiver and you

made a telephone call

well while you are using the phone

someone else on a different extension in

the same house couldn't lift up the

phone and make a phone call at the same

time right because you can only have one

signal on the wire at the time those are

the two different types of signaling

that's used