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.