Post on 06-Apr-2018
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hjavam@gmail.com Computer Networking:A Top Down Approach
Featuring the Internet,
3rd edition.Jim Kurose, Keith RossAddison-Wesley, July
2004.
http://groups.google.com/group/inteng-azad-uni
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Network Applications
.
:
.
.
)web Application:(
)
web browser(.
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.1Client/Server
.2P2P)Peer to Peer(
.3Hybrid
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Client/Server
ServerClient
.
WEBLoginEmail.
Clientserver
.
12
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Peer to Peer
Peer
.
P2P
Peer
PeerPeer.
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Hybrid
.
)Instant Message(Yahoo Messenger.
server)Client/Server(
Online)P2P(
P2PHybrid)edonkey.(
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process
process.
process
.Process
)messages(.
.
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process5TCP/IP
applicationtransport
networkdata linkphysical
applicationtransportnetworkdata linkphysical
applicationtransportnetworkdata linkphysical
message
ProcessA
ProcessBProcessC
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ProcessClient/Server
.
.
(Initial).
(listen).
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Socket
ProcessSocketProcess.
SocketProcess.
Process
.Socket
.SocketAPI
.
.
process
TCP withbuffers,variables
socket
host orserver
process
TCP withbuffers,variables
socket
host orserver
Internet
controlledby OS
controlled byapp developer
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Process)(lab:netstat
ProcessProcess
Process. .1:IP.2Process:
port
Client process
10.0.0.20:3023
server process
10.0.0.10:80
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(well Known)
portProcess.port80
port252021
porthttp://iana.org.
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1
netstat
.
)(netstat.
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2
.:
.
10.0.0.2/24.
IP IP
Accept TCP 80 any 10.0.10.0/24 10.0.0.0/24 1
:
:
:
:
:
:
:
:
:
:
:
:
:
:
Drop any any any Any Any Last
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.
.1
.2 (Syntax of messagetypes)
.3(Semantics of the fields)
.4 Process.
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.
.
)HTML(
HTTP
HTTP
.
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(Public-domain protocols)RFC
(interoperability)
HTTP:
RFC-2616HTTP.IEFirefoxOpera
ApacheIIS.
(Proprietary protocols):Napster, KaZaA
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:.1Data Loss:
.multimedia
..1Bandwidth:
(effective).
32Kbps .(elastic).
.1Timing)Delay:(
.
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Application Data loss Bandwidth TimeSensitive
file transfer no loss elastic no
e-mail no loss elastic noweb documents no loss elastic (few kbps) no
real-time
audio/video
loss-tolerant
audio: few kbps-1Mbps
video:10kbps-5Mbps
yes, 100s ofmsec
stored
audio/video
loss-
tolerant
same as above yes, few sec
interactivegames
loss-tolerant
few kbps-10kbps yes, 100s ofmsec
instantmessaging
no loss elastic yes and no
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TCP
::TCPclientServer.
.TCP
..
::process
TCP.::.
::
.
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UDP
UDP ..UDP
processU
DP process.
processUDP
UDP
U
DP.
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.
applications application-layer
protocol
underlying
transport protocole-mail SMT P [RFC 2821] TCP
remote terminal access Telnet [RFC 854] TCP
web HTTP [RFC 2616] TCP
file transfer FT P [RFC 959] TCPremote file server NFS [McKusik] UDP or TCP
streaming multimedia proprietary
(e.g., Real Networks )
UDP or TCP
internet telephony proprietary
(e.g., Net2Phone )
Typically UDP