TCP/IP from 10,000 feet
Skills: none
Concepts: local area network, router, inter network,
the TCP/IP layered software “stack”, layer functions,
layer protocols, dumb versus smart networks
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Where does this topic fit?
• Internet concepts
– Applications
– Technology
– Implications
• Internet skills
– Application development
– Content creation
– User skills
TCP/IP from the outside
Application
Program, for
example, a
Web client
A TCP/IP network
Application
Program, for
Example, a
Web server
Local area networks
LAN
LAN
A router at the edge
?
?
?
From LAN to Internet to LAN
The Internet a network of networks
The path between two hosts
Crossing the LAN
R
LAN
From the LAN to the ISP’s router
Forward to next network
Forward to next network
Forward to next network
Reaches the destination network
Delivered by the data link layer
Client
Server
A router goes down
Net routes around problems
TCP/IP, the very big picture
Layer
Function
Application programs
Do useful work like Web browsing,
email, and file transfer
TCP/IP communication
software
Handle communication between
the client and server
Function of each layer
Layer
Function
Application Do useful work like Web browsing, email, and file
transfer
Transport
Transport data between application programs
running on two hosts
Internet
Route packets between networks (inter network)
Data link
Send data within the local area network
Physical
Specify hardware characteristics and ways to
differentiate between ones and zeros
Function of each layer
Layer
Function
Application Do useful work like Web browsing, email, and file
transfer
Transport
Transport data between application programs
running on two hosts
Internet
Route packets between networks (inter network)
Data link
Send data within the local area network
Physical
Specify hardware characteristics and ways to
differentiate between ones and zeros
Function of each layer
Layer
Function
Application Do useful work like Web browsing, email, and file
transfer
Transport
Transport data between application programs
running on two hosts
Internet
Route packets between networks (inter network)
Data link
Send data within the local area network
Physical
Specify hardware characteristics and ways to
differentiate between ones and zeros
Transport layer protocols
TCP (transmission control protocol)
or
UDP (universal datagram protocol)
Data link layer protocols
Ethernet
or
Wifi
Ethernet
or
Wifi
Internet layer protocol
IP (the internet protocol)
Application layer protocols
Different
protocols
for each
application
Different
protocols
for each
application
Physical layer standards
or
Protocols at each layer
Layer
Protocol
Application Many depending upon the application
Transport
TCP or UDP
Internet
IP
Data link
Ethernet and WiFi most common
Physical
Many wireless, copper wire, optical fiber, etc.
By design, the Internet is dumb
The Internet
The telephone network
The telephone network is smart
Summary
Layer
Function
Application Do useful work like Web browsing, email, and file
transfer
Transport
Transport data between application programs
running on two hosts
Internet
Route packets between networks (inter network)
Data link
Send data within the local area network
Physical
Specify hardware characteristics and ways to
differentiate between ones and zeros
Self-study questions
1.
Do you have a LAN at home? How many computers connect to it
2.
There is only one connection leading out from your home router –
where does it forward packets to?
3.
When you connect to the Internet using a mobile device like a
phone or a tablet, are you connecting to a network that is
connected to the Internet? Explain.
4.
We saw that there were two commonly protocols at the transport
layer – TCP for reliable communication and UDP for fast, but
unreliable communication. Which would an application
programmer use for a file-transfer program? Which would an
application programmer use for a streaming video program?
Explain your answers.
Do you recall the names of the TCP/IP protocol layers?
Application
Physical
Do you recall the functions of the software at each layer?
Application:
Transport:
Internet:
Data link:
Physical:
Do you recall the protocol(s) used at each layer?
Application:
Transport:
Internet:
Data link:
Physical:
Resources