> In information technology and on the Internet, infrastructure is the physical hardware used to interconnect computers and users. Infrastructure includes the transmission media.Infrastructure also includes the software used to send, receive, and manage the signals that are transmitted.
> In some usages, infrastructure refers to interconnecting hardware and software and not to computers and other devices that are interconnected. However, to some information technology users, infrastructure is viewed as everything that supports the flow and processing of information.
INTERNET PROTOCOL (IP)
- IP specifies the format of packets, also called datagrams, and the addressing scheme. Most networks combine IP with a higher-level protocol called Transmission Control Protocol (TCP), which establishes a virtual connection between a destination and a source.
- IP is the primary protocol in the Internet Layer of the Internet Protocol Suite and has the task of delivering datagrams from the source host to the destination host solely based on the addresses. For this purpose, IP defines datagram structures that encapsulate the data to be delivered. It also defines addressing methods that are used to label the datagram source and destination.
- IP address consist of 32 bits (shown as 4 octets of number from 1-225 represented in decimal form instead of binary).
- Consisit of two part: network & host/node of network
- Class of address determines which part belongs to network add & which part belongs to node address.
- Network Classess Note..
CLASS A NETWORK
- Binary add start with 0 therefore decimal can be anywhere from 1-126
- First octet (8 bits) identify network, other 3 octets identify the host.
CLASS B NETWORK
- Binary add start with 10 therefore decimal can be anywhere from 128-191.
- 127 reserved for LOOPBACK & used for internal testing on local machine.
- First 2 octet (16 bits) identify network, other 2 octets indicate the host.
CLASS C NETWORK
- Binary add start with 110 therefore decimal can be anywhere from 192-223.
- First 3 octet (24 bits) identify network, other 1 octet indicate the host.
CLASS D NETWORK
- Binary add start with 1110 therefore decimal can be anywhere from 224-239.
- To support multitasking (multi layers).
CLASS E NETWORK
- Binary add starts with 1111 therefore decimal can be anywhere from 240-255.
- Used for experimentation.
DOMAIN NAME SYSTEM (DNS)
- DNS is an Internet service that translates domain names into IP addresses. Because domain names are alphabetic, they're easier to remember. The Internet however, is really based on IP addresses.
- Every time you use a domain name, therefore, a DNS service must translate the name into the corresponding IP address. For example, the domain name www.example.com might translate to 198.105.232.4.
- The DNS system is, in fact, its own network. If one DNS server doesn't know how to translate a particular domain name, it asks another one, and so on, until the correct IP address is returned.
- The Domain Name System makes it possible to assign domain names to groups of Internet resources and users in a meaningful way, independent of each entity's physical location.
- Because of this, World Wide Web (WWW) hyperlinks and Internet contact information can remain consistent and constant even if the current Internet routing arrangements change or the participant uses a mobile device.
- Internet domain names are easier to remember than IP addresses. Users take advantage of this when they recite meaningful Uniform Resource Locators (URLs) and e-mail addresses without having to know how the computer actually locates them.
- DNS also stores other types of information, such as the list of mail servers that accept email for a given Internet domain. By providing a worldwide, distributed keyword-based redirection service, the Domain Name System is an essential component of the functionality of the Internet.
- INTERNET ACCESS PROVIDER (ISP)
- An Internet service provider (ISP) is an organization that provides access to the Internet. Internet service providers can be either community-owned and non-profit, or privately owned and for-profit.
- Access ISPs directly connect clients to the Internet using copper wires, wireless or fiber-optic connections.
- ISP, it refers to a company that provides Internet services, including personal and business access to the Internet. For a monthly fee, the service provider usually provides a software package, username, password and access phone number.
- Equipped with a modem, you can then log on to the Internet and browse the World Wide Web and USENET, and send and receive e-mail. For broadband access you typically receive the broadband modem hardware or pay a monthly fee for this equipment that is added to your ISP account billing.
- In addition to serving individuals, ISPs also serve large companies, providing a direct connection from the company's networks to the Internet. ISPs themselves are connected to one another through Network Access Points (NAPs). ISPs may also be called IAPs (Internet Access Providers).
- HTTP
- HTTP stands for HyperText Transfer Protocol. Hypertext is a multi-linear set of objects, building a network by using logical links (the so called hyperlinks) between the nodes (e.g. text or words).
- HTTP is the protocol to exchange or transfer hypertext.
- It’s what browsers and web servers rely on for exchanging data so that you can surf the web, browse web pages, search Google, download pictures, and viewing YouTube.
- Developed by W3C and IETF in the last few years of the last century, it’s part of a bigger protocol family created to support the whole Internet, called TCP/IP. As a subset, HTTP’s responsibility is the World Wide Web or WWW.
- By HTTP definition and usage, it’s fundamentally an information exchanging procedure standard between 2 communicating parties or computers, such as the client and the server.
- While you type a URL address in the web browser, the browser will have to know the protocol to use when fetching the remote resource such as a web page or a picture at that address. Failing to do so, as we most of the time would do without the http:// part, the browser will assume HTTP by default and prepend it to the URL address.
- A web address representing an access point on the web almost always start with http://, immediately followed by the web page address such as in this one ‘http://www.google.com/’.
- This is the root web site address of Google. And browsing to it, the server located at the address would serve up the home page of Google. This is all beyond the meaning of HTTP however, what this basically means is that, a web address consists of 2 basic parts: Protocol (HTTP) & Address (WWW.GOOGLE.COM).
