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1.1.What is the Internet?, Whats the internet: a service view - Coggle…
1.1.What is the Internet?
fun internet connected devices
IP picture frame
Tweet-a-watt
Web enabled toaster + weather forecaster
Slingbox watch, control cable TV remotely
sensorized bed mattress
Internet phones
What's the internet: "nuts and bolts" view
billions of connected computing devices:
hosts = end systems
running network apps
communication links
fiber, copper, radio, satellite
transmission rate: bandwidth
packet switches: forward packets (chunks of data)
routers and switches
Internet: "network of networks"
Interconnected ISP's
protocols
control sending and receiving of messages
-- e.g.TCP, IP, HTTP, Skype, 802.11
Internet standards
RFC: Request for comments
IETF: Internet Engineering Task Force
Whats a protocol
network protocols
machines rather than humans
all communication activity in internet governed by protocols
protocols define format, order of messages sent and received among networks entities, and actions taken on message transmission, receipt
E.g.
Other human protocols?
OSI vs TCP/IP Model
Open System Interconnection
Layer 7 - Application layer
Layer 6 - Presentation
Layer 5 - Session
Layer 4 - Transport
Layer 3 - Network
Layer 2 - Data Link
Layer 1 - Physical layer
Transmission Control Protocol/Intermet Protocol
Layer 4 - Application layer
Layer 3 - Host-to-Host/Transport
Layer 2 - Internet layer
Layer 1 - Network Access layer
1.2.network edge?
A closer look at network structure:
network edge:
hosts: clients and servers
servers often in data centers
access networks physical media:
wired
wireless communication links
network core
interconnected routers, switches
network of networks
Access networks and Physical media
How are end systems connected to edge devices?
residential access nets
institutional access networks(school, company)
mobile access networks
Bandwidth(bits per second) of access network?
shared or dedicated?
Guided
Twisted-Pair Copper Wire
Coaxial Cables
Fibre Optics
Unguided
Terrestial Radio channels
Satellite Radio channels
Bluetooth
Wifi
ZigBee
Access network: digital subscriber line (DSL)
Whats the internet: a service view
infrastructure that provides services to applications
Web, VoIP, email, games, e-commerce, social nets, ...
provides programming interface to apps
hooks that allow sending and receiving app programs to "connect: to internet
provides service options, analogous to postal service
