Network Protocols

In 1978, the Advanced Research Projects Agency (ARPA) developed the foundational set of protocols required for using the Internet. These protocols are known as the Transmission Control Protocol/Internet protocol Suite, or TCP/IP.

TCP/IP

The TCP/IP protocol is used to communicate over the Internet. Ethernet is a LAN protocol, which might be used in addition to TCP/IP in some networks, but it is not needed to communicate over the Internet.

The Internet Engineering Task Force (IETF) is a large open international community of network designers, operators, vendors, and researchers concerned with the evolution of the Internet architecture and the smooth operation of the Internet. The mission of the IETF is to make the Internet work better by producing high quality, relevant technical documents that influence the way people design, use, and manage the Internet.

IETF

Ietf Logo.Svg (binary/octet-stream)

Caption: : https://www.ietf.org/

Every device or machine that is connected to the Internet has a unique Internet protocol (IP) address. An IP address consists of seven digits broken up into four groups (called octets) separated by decimal points, each of which must be from 0 to 255. An example of an IP address would be 426.6.35.4. These numbers can be automatically provided or assigned by a system administrator.

IP Addresses

IP addresses are not the only way to navigate the Internet. In fact, end users rarely locate resources through the explicit use of IP addresses. Consider your school's website. Do you know your school's webserver IP address? How do you locate the page? The Domain Name System enables network users to locate a device semantically through a layer of abstraction.

Domain Name system

The right to use a domain name is delegated by domain name registrars which are accredited by the Internet Corporation for Assigned Names and Numbers (ICANN) or other organizations such as OpenNIC, that are charged with overseeing the name and number systems of the Internet.

ICANN

In addition to ICANN, each top-level domain (TLD) is maintained and serviced technically by an administrative organization, operating a registry. A registry is responsible for operating the database of names within its authoritative zone, although the term is most often used for TLDs.

A registrant is a person or organization who asked for domain registration. The registry receives registration information from each domain name registrar, which is authorized (accredited) to assign names in the corresponding zone and publishes the information using the WHOIS protocol. (Wikipedia).

WHOIS

URLs (Universal Resource Locator) are used to locate documents (or other types of files such as an image or sound file) anywhere on the Internet.

URL

The URL contains the address of the LAN or WAN and the specific computer from which the file is to be retrieved, but specifies the file’s address, not just the computer’s address.

The basic parts of a URL often provide "clues" to where a web page originates and who might be responsible for the information at that page or site. URLs have three basic parts: the communication protocol the server name the resource ID The protocol is shown at the beginning of the URL before the double slash (//); the server name is between the double slash (//) and the first single slash (/); and the resource id is everything after the first single slash (/).

Parts of a URL

Let's take a look at the URL for this page: http://www.mrsrush.net/apcsp/internet/index.html Can you identify: protocol: server name: resource ID

http://www.mrsrush.net/apcsp/internet/index.html   protocol:  http server name: www.mrsrush.net resource ID:  apcsp/internet/index.html

The protocol identifies the method (set of rules) by which the resource is transmitted. All Web pages use HyperText Transfer Protocol (HTTP). Thus, all web URL's (including my website) begin with http://.

HTTP

We can enter a web address in the browser without typing the protocol because the browser can be programmed to add it.

The server name identifies the computer on which the resource is found. (Computers that store and "serve up" web pages are called remote servers.) This part of the URL commonly identifies which company, agency or organization may be either directly responsible for the information, or is simply providing the computer space where the information is stored. Web server names often begin with the letters www, but not always. Why do you think that not all servers use the www? Remember that the World Wide Web sits on top of the Internet and not everything that is on the Internet is also a part of the World Wide.

World Wide Web

The server name always ends with a dot and a two- or three-letter extension called the domain name. The domain is important because it usually identifies the type of organization that created or sponsored the resource. Sometimes it indicates the country where the server is located. 

Domains

.com which identifies company or commercial sites .org for non-profit organization sites .edu for educational sites .gov for government sites .net for Internet service providers or other types of networks us identifies the country

The most common domain names

Tld (binary/octet-stream)

Caption: : This statistic gives information on the distribution of worldwide top level domains as of May 2018. As of that month, 46.5 percent of all global websites used a .com top-level domain.

The resource ID is the name of the file for the page and any directories or subdirectories under which it is stored on the specified computer. The part of the resource ID after the last slash (/) is the file name for the specific page or other resource. The file name ends with a three or four letter designation that specifies the file type.

Resource ID