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Computer Networks - Basic Characteristics - YouTube
Channel: Neso Academy
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hello everyone welcome back to the
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computer networks course and today we
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shall see the basic characteristics of
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computer network before we step into the
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basic characteristics we shall set some
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outcomes of this session upon the
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completion of this session we will be
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able to understand the need for fault
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tolerant networks and scalable networks
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we shall understand what is quality of
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service and we shall also understand why
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do we need security in computer networks
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there are 4 basic characteristics any
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computer network should possess fault
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tolerance scalability quality of service
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and security if we say there is a
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computer network and that computer
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network should be fault tolerant it
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should be scalable it should provide
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quality of service and it should also
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provide security we shall see each of
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these in a detailed manner firstly fault
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tolerance fault tolerance is the ability
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of the computer network to continue
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working despite failures and it should
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ensure there is no loss of service for
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example if we have a computer network
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and if there is a problem inside the
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computer network but still the computer
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network should work even after failures
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and thereby there is no loss of service
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before we go on to this example part you
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just visualize the scenario imagine you
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are going home back from your college
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you know very well about the best route
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to reach your home and you prefer taking
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this regular best route unfortunately
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there is a blockage and you cannot take
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this route further what will you do now
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will you go to your college back or you
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will find the next available route to
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reach your home I guess we all will find
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the next available route and we will
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take that route to reach home this is
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what we call as fault tolerance we shall
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see an example for fault tolerance now
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let us assume that these two entities
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are communicating with each other this
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computer and this web server through
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switch this wireless router this link
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this router one router 3 router 5 switch
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and web server
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unfortunately there is a failure maybe
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either in the link or this router has
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gone down so this router instead of
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forwarding the data through this way it
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forwards the data to router two so that
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this communication between this computer
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and this webserver is not affected
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because of this failure this is what
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exactly fault tolerance I hope now you
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understood why do we need fault tolerant
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network because we need to work despite
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failures and we need to ensure there is
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no loss of service this is what exactly
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fault tolerance now we shall see the
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second basic characteristic scalability
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it is the ability to grow based on the
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needs and have good performance even
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after growth for example if there are 10
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computers in a network and if again 10
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computers are added to the network this
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network should work as like the same
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even after adding these 10 computers we
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shall see an example for the scalable
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Network the best example for a scalable
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network is the internet even this moment
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many new devices are connecting to
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internet and communicating to each
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other's internet handles this very
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perfectly and always gives hope for the
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newcomers this is what we exactly called
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as scalability in this example assume
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100 computers are connected to router 3
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and we expect our computer network to
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work as like the same even after adding
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these hundred devices this is what we
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call a scalability and this is the
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ability to grow based on the needs and
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have good performance even after the
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growth of the network so far we have
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seen fault tolerance and scalability now
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we shall see the third basic
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characteristic of computer network the
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quality of service it is the ability to
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set priorities and manage data traffic
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to reduce data loss and delays for
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example if a router receives two packet
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at a time or two data at a time and this
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router should know to which data it
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should process first this is what we
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call a set priorities
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I shall explain about this quality of
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service in a detailed manner with an
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example have you noticed something is
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new in this picture which was not there
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in our previous lecture it is the voice
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over IP form
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vivo IP stands for voice over IP phone
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and this phone is different from our
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traditional landline phone this voice
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over IP phone since the voice data
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through the internet whereas our
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traditional landline phone since the
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voice data through the dedicated
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telephone network so this voice over IP
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phone is like our whatsapp call in
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whatsapp call our voice data is sent to
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the destination through the internet but
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not through the telephone network you
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may be wondering why I have brought in
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this voice over IP Phone
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I shall explain you why I have brought
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in this voice over IP Phone for a reason
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let's assume this guy is sending some
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email data to an email server through
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router one at the same time there are
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two guys who are talking over voice over
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IP Phone through Internet
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the situation is two guys are sending
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data at the same time where this router
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one is experiencing both the traffic at
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the same time one is the email traffic
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another one is the voice traffic that is
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the real-time communication now the
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question is to which data this router 1
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will give priority whether to the
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real-time communication or to the email
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data actually route of 1 will process
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voice over IP phones data why because it
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is a real-time communication in
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real-time communication delays are not
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accepted whereas delays are not a
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problem in email communication a delay
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of one second in an email communication
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is not going to hurt the communication
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whereas a delay of one second in a
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real-time communication matters a lot
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and that is why this router gives
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priority to real-time communication than
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normal communication when router
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experiences two different kinds of data
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at the same time this router should be
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able to know to which data should you
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priority this is what we call as quality
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of service the main aspect of this
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quality of services that it handles law
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also it handles the delay now we shall
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see the final characteristics of
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computer network that is the security it
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is the ability to prevent unauthorized
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access misuse or forgery and not only
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prevention Network should also provide
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confidentiality integrity and
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availability to understand why do we
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need security we shall visit this
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example suppose someone from this
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computer is sending some confidential
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information to amazon.com once the data
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leaves our computer it is not in our
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hands Internet has good guys as well as
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bad guys whom we call as attackers
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please note attackers are bad guys
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assume our confidential information is
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flowing through router 3 and what if an
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attacker steals this information from
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router 3 they get access to our computer
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they can misuse or they can also involve
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in forgery so it becomes an important
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task for a computer network to provide
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confidentiality that is the data which
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is not sent just like that as what we
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had sent it means if it is a
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confidential data this data is converted
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to a different form if that form can be
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understandable only by the sender and
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the receiver at the same time there is
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no modification of data sent should be
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there that is this network should
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provide integrity whatever the sender is
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sending that only the receiver should
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receive so this property we call as
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integrity attacker always tried to
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deface this web servers so that this
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resource becomes unavailable for access
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so it becomes the ultimate
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responsibility of a computer network to
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provide security because network should
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prevent unauthorized access misuse and
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forgery and it should also provide
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confidentiality integrity and
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availability I hope now you are clear
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with all the basic characteristics of a
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computer network a fault tolerant
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Network a scalable network the quality
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of service and security thank you for
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watching we shall meet again in the
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upcoming lectures
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[Applause]
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[Music]
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