internet

references

• • Don Parker. The basic journey of a packet

  • Berners-Lee, Tim, Roy Fielding, and Henrik Frystyk. Hypertext transfer protocol--HTTP/1.0. No. RFC 1945. 1996. (read at least sections 1&2)

  • Berners-Lee, T., Fielding, R., & Masinter, L. 2004. Uniform resource identifier (URI): Generic syntax (No. RFC 3986).

  • Postel, Jon. 1994. Domain Name System Structure and Delegation. RFC 1591, Network Working Group.

  • Severance, C. 2015. Roy T. Fielding: Understanding the REST Style. Computer, 48(6), 7-9.

some notes

• The internet protocol suite

  • • Maintained by the IETF

    • Layers

      • http://en.wikipedia.org/wiki/Link_layer (e.g. Ethernet)

        • Communication on local networks

        • Ethernet developed at Xerox PARC by Metcalfe and Boggs

          • Metcalfe later founds 3com, now part of HP

        • Others: DSL, ISDN, FDDI

      • Internet layer (IP)

        • Connects local networks, "internetworking"

        • Developed by Kahn and Cerf

        • IP: internet protocol

      • Transport layer (e.g., TCP)

        • Host to host communication

        • Developed by Kahn and Cerf

        • TCP: transmission control protocol

        • Others: UDP, DCCP...

      • Application layer (e.g. HTTP)

        • Data specific, app to app or process to process communication

        • Others: DHCP, DNS, FTP, IMAP, IRC, LDAP, POP, RPC, SMTP, SSH, Telnet...

• • Terminology

    • IP address: numeric address of a networked machine

      • Static: unchanging

      • Dynamic: assigned on networks dynamically, for automation and efficient use of address space

    • domain name: a character string identifying a networked machine/resource/service

      • root domain: nameless

      • subdomains:

        • first level/top level domains (TLDs)

          • generic: .com, .org, .edu...

          • country: .uk, .de...

          • administered by ICANN

        • second and third level

          • reserved for users and sold by domain name registrars, authorized by ICANN

      • syntax

        • hierarchy of domains descends right to left

        • rightmost: the tld

        • hostname: any domain name that has at least one associated IP address

          • Not all domain names are hostnames

    • domain name system (DNS)

      • the hierarchical domain name system

    • domain name server

      • one of many distributed servers that turn domain names into IP addresses

    • URL: uniform resource locator - reference to a network resource

      • Developed by Tim Berners-Lee

      • syntax: scheme://domain:port/path?query_string#fragment_identify

        • scheme: app layer protocol, e.g. http

        • domain: domain name or IP address

        • port: which port to connect to. Defaults exist for each scheme

        • path: where (e.g. directory) to find the resource on the server

        • query string: data to be passed to the server, name value pairs separated by ampersands

        • fragment identifier: a part or position within the resource or document, e.g. a section

    • HTTP: hypertext transfer protocol - app level protocol for hypermedia information systems

      • Developed by Tim Berners-Lee

      • A request response protocol in the client server model.

        • E.g. browser is client, and site runs on server

      • Methods that a client can request

        • GET: a request for the page resource, for example, some html. Should have no side effects. Part of the http 1.0 spec.

        • POST: submits some data for processing, e.g. to an html form. Http 1.0.

        • HEAD: a request for the header of the page resource only, not the body. When you want meta information only. Http 1.0.

        • PUT: uploads a new version of the resource. Http 1.1.

        • DELETE: deletes the resource. Http 1.1.

        • TRACE: return the request as received, to examine any changes made along the way. Http 1.1.

        • OPTIONS: returns the methods supported by the server. Http 1.1.

        • CONNECT: convert connection to a tunnel, usually for encryption. Http 1.1.

        • PATCH: partial modification of resource.