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Protocol
              A protocol is a set of rules or guidelines that govern how data is transmitted and received between devices
              or systems in a network. Protocols may be applied by hardware, software or a combination of the two. The
              primary protocol of the Internet is TCP/IP protocol which stands for Transmission Control Protocol/Internet
              Protocol. TCP is responsible for connection-oriented transmission and IP is responsible for connectionless
              transmission that represents the logical address of the host machine, for example http:// for accessing HTML
              documents, https:// for accessing some ‘secure’ HTML documents.

              Uniform Resource Locator (URL)
              It  identifies  the  location  of  a  website  or  a  web
              page on the Internet. Each web page has a unique
              address called a URL that identifies its location on
              the Internet. Web browsers utilises the URL to open
              or retrieve files on a Internet. The format of a URL
              consists of different parts.
              The first part of the address (URL) indicates the protocol or service being used. It gives information to the
              browser about the type of server to connect to and by which protocol.

              The second part of the URL is a Full Qualified Domain Name (FQDN) which identifies the web address running
              on the server.
              The third part is the path name which refers to the location of files. The path name is always preceded by a
              single slash ‘/’ after the domain name. The fourth part is the file extension.
              URL can be categorised into Absolute URL and Relative URL.
                Absolute URL: Absolute URLs are the URLs with a complete Internet address specifying the location of a
                 resource. An Absolute URL includes protocol, host, path and name of the resource.

                For example : www.thetouchpad.com/index.htm.
                Relative URL: A relative URL is not fully complete but it inherits the protocol, host and path information
                 from its parent document (the document file that links to it). Relative URLs are used to refer to links on the
                 same server as the page that contains them.

              Most of the web pages are identified by relative URL where hyperlinks point to (last destination) documents
              and other files which are located on the same site. eg. link.htm.


               SESSION             9   Communication and Networking—Introduction to e-Mail


              Electronic Mail (e-mail) is an online mailing service provided on the Internet by which one can send messages
              to any person around the world through computing devices. It has become the fastest, easiest and cheapest
              means of communication for business, governance, administration, education, tourism, etc.
              An individual who avails the service of the Internet must have a unique e-mail
              address. Messages can  be  sent and  received  using an  e-mail ID that  can  be
              accessed from anywhere at any time, as long as there is Internet connectivity. Mails
              are received in a Inbox of an e-mail recipient. No two e-mail IDs can be identical.
              For example, a typical e-mail address would look like: info@orangeeducation.com.







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