14th week: internet infrastructure
Internet infrastructure
Hierarcy of networks
In order to
connect to internet, we need:
¨ Computer
¨ Web browser
¨ Internet access (ISP)
All of this
look so easy, what you need to do is just find a computer, connect to a WIFI or
internet, click on the web browser which installed in it…that’s all.But the
exactly policy and procedures to bring to internet is quite
complicated.
Internet protocol (IP)
§ provide a common layer over
dissimilar network
§ move packets among “host” computer thru
gateways
§ each
computer assign a unique IP address
§ IP address consist of 32 bits (shown as 4 octets of
numbers from 0-225 represented in decimal form
instead of binary)
·
168.212.226.204
·
10101000.11010100.11100010.11001100
§ consists of 2 part:
·
Identifying
the network
·
Identifying
the node/host
§ Class of addresses will part it into
network add part and node part.
§ All nodes on a given network share
the same network prefix have a unique host number
class
|
Class A
|
Class B
|
Class C
|
Class D
|
Class E
|
Binary add
|
0
|
10
|
110
|
1110
|
1111
|
Decimal no
|
1 to 126
|
128 to 191
|
192 to 223
|
224 to 239
|
240 to 255
|
Identify network
|
First octet, first 8 bits
|
First 2 octet, first 16 bits
|
First 3 octet, first 24 bits
|
support multicasting
|
experimentation
|
example
|
102.168.212.226
|
102.168.212.226
|
102.168.212.226
|
102.168.212.226
|
§ So where is the decimal no of 127?
§ Number 127 is for loopback, used for internal
testing on local machine
Domain name system (DNS)
© Domain name is alphabetic that we
usually use to search on internet (or we commonly call it website name)
© Internet service that translates
domain names like www.yahoo.com into numerical IP address like 204.62.131.129
© Moe.gov.my
© Why we use DNS? = domain names are
alphabetic (easier to
remember)
Internet servise provider (ISP)
ª Or IAPs
(Internet access providers)
ª Is an organization that provides access to the internet
ª Two type: community-owned
and non-profit, privately owned and
for-profit
ª User can access ISP to connect the
internet via using wires, wireless or fiber-optic connections.
Hypertext transfer protocol (HTTP)
ª An application protocol for
distributed, collaborative, hypermedia information system.
ª Foundation of data communication for the World Wide
Web.
ª Hypertext = multi-linear set of objects, building a network by using logical link or hyperlinks between the nodes
(text or words).
ª HTTP is the protocol to exchange or transfer hypertext.
Hypertext transfer protocol
secure (HTTPS)
ª Combination of HTTP and SSL/TLS protocol.
ª From the name we know that it is in
secure.
ª It provides encrypted communication: prevent eavesdropping, securely identify web
server communicating.
ª Primarily used for e-payment transactions, e-mail
and sensitive transaction in corporate information system.
ª Now, widespread use for protecting page authenticity
on all type of websites, securing
accounts, keeping user communication, identity and browsing history private.
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