Transcript Internetworking

Internetworking
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What is internetworking?
 Connect multiple networks of one or more organizations
into a large, uniform communication system.
 The resulting system is called an internetwork or
internet.
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What is Internet?
 The Internet is the specific global internetwork that grew
out of ARPA-NET for communication of between
computer located anywhere in the world
Protocols
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Each intermediate network must agree to
handle transit in exchange for the right to
send traffic throughout the internet.
Internetworking protocols
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All computers and routers in an internet must
agree on a common set of internetworking
protocols.
What is a protocol? revisited
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A set of syntactic and semantic rules for communication.
details of message formats
How a computer should respond when a message arrives.
How a computer handles errors or.
Independent of lower layers or hardware.
TCP/IP protocol
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TCP/IP is the most widely used internetworking
protocol suite.
 TCP: Transmission Control Protocol.
 IP: Internet Protocol.
TCP/IP is now the defacto standard for
internetworking protocols.
TCP/IP suite
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Here are some of the key features provided
by TCP/IP suite:
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Packet switching
Logical addressing
Dynamic rooting
Name resolution
Packet switching
The data is divided in small chunks
“packets”
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The packets are transmitted independently
Possibly by different routes
And reassembled at the other end.
This allows a faster transmission
Logical addressing
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Every computer has physical address
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Ethernet address 48 bits (MAC address)
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90:AF:F4:CA:BA:03
Burned into the chip at the factory
Physical addresses are of different formats
With no hierarchical scheme
Uniform format: IP addresses
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32 bits identifying the network and the host.
Two systems can not connect to the Internet with the same
address at the same time.
Translation of IP to Ethernet address and vice versa.
Dynamic rooting
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Different routes can be taken from source to
destination
Router can choose a path for the data
depending on present conditions
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Path taken
Name resolution
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TCP/IP provides a mapping of domain name
and numeric addresses
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www.doc.gold.ac.uk = 158.223.1.108