Distributed and centralized database:
Nadra is the centralized database.in Islamabad.
Nadra is also the distributed database.
Because if we want to take the information of any citizens, then we can easily get the
The local place where
Beyond of the database , we use the network.
Banks database is also centrized database.
Atm is distributed database.
Remote login is done with the help of the distributed database.
Different media use for remote login.
When we save the data , then we saved is in any memory. Or cache or ram.
Buffer is a name of temporary space of loading the temporary files.
DISTRIBUTED GAMES used
Peer to peer network :
Directly communicate or data transfer or file transfer.
Web surfing (searching of data on the web is called the web surfing)
Communication oriented services:
When we sent or transfer the file or data , then reciver send the message ..and it is message of
authentication. Or acknowledgment. And it is reliable services.
It is unreliable.
Post office (in old ancient, letter are posted , may be misplace ..and it is unreliable.
(it is reliable)
Coeer services (it is more realible)
Connection oriented :
Received complete packets.
Sequence remain same.
It is opposite of above.
A has fixed ascii code 65 and its binary is 100000x
We sent the files but tranmsision is done and receiver is recived the files. And send the message of
Akknoledgment. And it is reliable connections.
When send the files but transmission is not doen and reciver wait some times and send the message of
And packet may be lost or files be lost.
Sender send the multiple files but the receiver have no space and he drop some of files.
It must be matched.’
In flow control , files is lost.
Congestion means data is block. And other reciver waits the data.
Sender packets send slowly when reciver send the message the traffic is heavey.
Tcp is connection oriented protocol
Other protocol is http, smtp etc.
User datagram protocol (UDP) multimedia
Above properties opposite.
Internet telephony (skype , messagner)
And its protocol is VOIP (voice over ip)
DIFFERENCE B/W TCP AND UDP
Table used it is good method.
Performs three handshake i.e:
Sender estbalsh the connection then data is transfer
Speed is high but cost is more.
Because it is reliable.
It is much faster than the tcp.
No connection is established.
May be change the sequence of data.
Video is unreliable services.
uDP protocol is used.
It is unreliable.
But its cost may be less
We can’t install the technology.
We install the software.
Whole communication is due to the protocol
if we send the mail, then we used the SMTP.and reciver is recived.,
and if we download the files or specific data, then we used the POP protocol
if we blocked the port no 80 i.e HTTP then pages can’t displayed. But interent is avaible.
If we send the mail to reciver and reciver also send the mail to other .then both of these are used same
option---encrpted it is used for office 7.
files may not be open due to the password.
2nd It may not be opened due to encrupt of files
Format may be change..
The network core:
wan and man used then is long distanvce.
Lan is small distance device.
Mostly we used the routers for the transmission.
Node means any device.
End systems mean starting and ending device which are connected to any system.
Guaranteed means we used the fixed path. As shown in fig. like red and blue.
Call setup required.
When call setup have been done, then conservation starts.
Normally moves in one specific path..beacuse no sharing.
It is part of net.
class is indivudal and is subnet.
And when seminar is held then it will be net..
We divided the fixed line into multiple users.
We gives the times to every user that is sepific.
Gives times slot to user but if user is not use then it will be lost.
Statsical time division multiplexing:
In which times slot we can give the user no 4.
And at the same times , user no 4 tranmist the 2 mb data.
Because user no 3 is replaced with the user no 4.
If it is idle.
Bursty traffic means in which we transfer the data in huge form.
Synchronous , we use the start bit and stop bit. Data is transmitted in th form of bits.
And in asynchronous, we use start block and end block.
In which data is transfer in the form of byte.