CHAPTER 1 INTRODUCTION TO COMPUTER NETWORKS Networking Basic
Summary
TLDRThis 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
- đ The script discusses three main ways to categorize computer networks: by host roles, geographic proximity, and signaling methods.
- đ» In a peer-to-peer network, hosts both provide and consume network services, functioning as both clients and servers.
- đ Peer-to-peer networks are easy to implement and inexpensive, but they lack centralized control and are not scalable.
- đ A key issue with peer-to-peer networks is the lack of centralized file storage, leading to potential data loss and difficulty in backup.
- đ„ïž Client-server networks assign specific roles to hosts, with servers providing resources and clients consuming them.
- đ Client-server networks are highly scalable and easier to support due to centralized services and resources.
- đ ïž The downside of client-server networks is the higher cost of specialized server operating systems and the need for extensive planning.
- đ 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.
- đą LANs can be within a single building or span multiple buildings, while WANs can connect different LANs across cities or countries.
- đ In a WAN, resources are typically located locally to minimize the need for data to travel long distances, improving efficiency.
- đĄ 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.
- đș 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
đ 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.
đ 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.
đĄ 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.
Mindmap
Keywords
đĄComputer Networks
đĄHost Roles
đĄPeer-to-Peer Network
đĄGeographic Proximity
đĄSignaling Methods
đĄLocal Area Network (LAN)
đĄWide Area Network (WAN)
đĄClient-Server Network
đĄScalability
đĄCentralized Control
đĄBaseband Signaling
đĄBroadband 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
Voir Plus de Vidéos Connexes
5.0 / 5 (0 votes)