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1.1 What Is the Internet? - Coggle Diagram
1.1 What Is the Internet?
Nuts-and-Bolts
host
end systems
[buildings]
communication links
[highways and roads]
made up of different types of
physical media
copper wire
Different links can transmit data at different rates, with the
transmission rate
of a link measured in bits/second.
optical fiber
radio spectrum
coaxial cable
packets
: resulting packages of information [trucks]
packet switches
[intersections]
takes a
packet
arriving on one of its incoming communication links and forwards that packet on one of its outgoing communication links.
routers
used in the network core
link-layer switches
(Network switches)
used in access networks
route
or
path
through the network:
The sequence of communication links and packet switches traversed by a packet
run
protocols
that control the sending and receiving of information within the Internet [TCP/IP]
Transmission Control Protocol (TCP)
Internet Protocol (IP)
Internet standards
are developed by the Internet Engineering Task Force (
IETF
)
its documents are called requests for comments (
RFCs
)
to resolve network and protocol design problems
HTTP
(for the Web)
SMTP
(for e-mail)
The
IEEE 802 LAN/MAN
Standards Committee specifies the Ethernet and wireless WiFi standards.
access the Internet through
Internet Service Providers (ISPs)
Each ISP is in itself a network of packet switches and communication links
Each ISP network, whether upper-tier or lower-tier, is managed independently, runs the IP protocol, and conforms to certain naming and address conventions
Services
an infrastructure that provides services to applications
applications include electronic mail, Web surfing, social networks, instant messaging, Voiceover-IP (VoIP), video streaming, distributed games, peer-to-peer (P2P) file sharing, television over the Internet, remote login, etc
applications are said to be
distributed applications
, since they involve multiple end systems that exchange data with each other
attached to the Internet provide an
Application Programming Interface (API)
that specifies how a program running on one end system asks the Internet infrastructure to deliver data to a specific destination program running on another end system
What Is a
Protocol
?
A
Human
Analogy
there are specific messages we send, and specific actions we take in response to the received reply messages or other events (such as no reply within some given amount of time)
it takes two (or more) communicating entities running the same protocol in order to accomplish a task
Network
Protocols
a computer network protocol with which you are probably familiar, consider what happens when you make a request to a Web server, that is when you type the URL of a Web page into your Web browser
A
protocol
defines the format and the order of messages exchanged between two or more communicating entities, as well as the actions taken on the transmission and/or receipt of a message or other event.