# Internet Protocol Analysis/Introduction

This lesson introduces Internet protocol analysis by looking at background information on the Internet protocol suite, the Request for Comments process and Internet standards, and comparing the Internet protocol suite to the Open Systems Interconnection (OSI) model.

## Readings

* Wikipedia: Internet protocol suite
* Wikipedia: Request for Comments
* Wikipedia: Internet Standard
* Wikipedia: OSI model

## Multimedia

* YouTube: Network Layers - OSI, TCP/IP Models - Part 1
* YouTube: Network Layers - OSI, TCP/IP Models - Part 2
* YouTube: Network Layers - OSI, TCP/IP Models - Part 3

## Activities

* Draw your own personal reference chart comparing the Internet protocol suite four-layer model to the OSI seven-layer model.
* Review Internet standards regarding private networks and see if your computer is on a private network.
* Review Wikipedia: April Fools' Day Request for Comments for a humorous look at networking standards.
* Consider why the OSI seven layer model is sometimes referred to as a theoretical model while the Internet protocol suite might be referred to as an operational model.

## Lesson Summary

* The Internet protocol suite is the set of communications protocols used for the Internet and similar networks. It is a four-layer model containing Link, Internet, Transport, and Application layers.
* The Internet protocol suite is maintained by the Internet Engineering Task Force (IETF).
* The Link layer contains communication technologies for a local network.
* The Internet layer connects local networks, thus establishing internetworking.
* The Transport layer handles host-to-host communication.
* The Application layer contains all protocols for specific data communications services on a process-to-process level.
* A Request for Comments (RFC) is a memorandum published by the Internet Engineering Task Force (IETF) describing methods, behaviors, research, or innovations applicable to the working of the Internet and Internet-connected systems.
* Requests for Comments are designated with a status of Informational, Experimental, Best Current Practice (BCP), Standards Track, or Historic. Standards-track documents are further divided into Proposed Standard, Draft Standard, and Internet Standard.
* Internet Standard is a special Request for Comments (RFC) or set of RFCs which is characterized by a high degree of technical maturity and by a generally held belief that the specified protocol or service provides significant benefit to the Internet community.
* Best Current Practice is a Request for Comments (RFC) that may include official rules, but which does not affect over the wire data and is not on the standards track.
* The Internet protocol suite protocols are deliberately not as rigidly designed into strict layers as in the OSI model.
* The Internet Link layer includes the OSI Data Link and Physical layers, as well as parts of OSI's Network layer.
* The Internet internetworking layer (Internet layer) is a subset of the OSI Network layer.
* The Internet Transport layer includes the graceful close function of the OSI Session layer as well as the OSI Transport layer.
* The Internet Application layer includes the OSI Application layer, Presentation layer, and most of the Session layer.

## Key Terms
### Advanced Research Projects Agency Network (ARPANET)

    The world's first operational packet switching network and the progenitor of what was to become the global Internet.

### Best Current Practice

    Mandatory IETF RFCs, including official rules, but which do not affect over the wire data and are not on the standards track.

### best effort delivery

    A network service in which the network does not provide any guarantees that data is delivered or that a user is given a guaranteed quality of service level or a certain priority.

### checksum

    A fixed-size datum computed from an arbitrary block of digital data for the purpose of detecting accidental errors that may have been introduced during its transmission or storage.

### communications protocol

    A system of digital message formats and rules for exchanging those messages in or between computing systems and in telecommunications.

### Defense Advanced Research Projects Agency (DARPA)

    An agency of the United States Department of Defense responsible for the development of new technologies for use by the military.

### encapsulation

    A method of designing modular communication protocols in which logically separate functions in the network are abstracted from their underlying structures by inclusion or information hiding within higher level objects.

### Ethernet

    A family of Link layer computer networking technologies for local area networks (LANs).

### Internet Architecture Board (IAB)

    The committee charged with oversight of the technical and engineering development of the Internet by the Internet Society (ISOC).

### Internet Drafts

    A series of working documents published by the IETF.

### Internet Engineering Task Force (IETF)

    Develops and promotes Internet standards, cooperating closely with the W3C and ISO/IEC standards bodies and dealing in particular with standards of the Internet protocol suite (TCP/IP).

### Internet Protocol (IP)

    The principal communications protocol used for relaying datagrams (also known as network packets) across an internetwork using the Internet Protocol Suite responsible for routing packets across network boundaries.

### Internet Society (ISOC)

    An international, non-profit organization founded in 1992 to provide leadership in Internet related standards, education, and policy.

### Internet Standard

    A normative specification of a technology or methodology applicable to the Internet.

### internetworking

    The practice of connecting a computer network with other networks through the use of gateways that provide a common method of routing information packets between the networks.

### medium

    A material substance (solid, liquid, gas, or plasma) that can propagate energy waves.

### Open Systems Interconnection (OSI) model

    A product of the Open Systems Interconnection effort at the International Organization for Standardization for characterizing and standardizing the functions of a communications system in terms of abstraction layers.

### packet

    A formatted unit of data carried by a computer network.

### packet header

    Data placed at the beginning of a block of data being stored or transmitted.

### protocol stack

    An implementation of a computer networking protocol suite.

### Request For Comments (RFC)

    A memorandum published by the Internet Engineering Task Force (IETF) describing methods, behaviors, research, or innovations applicable to the working of the Internet and Internet-connected systems.

### router

    A device that forwards data packets between computer networks.

### Transmission Control Protocol (TCP)

    A Transport layer protocol that provides reliable, ordered delivery of a stream of octets from a program on one computer to another program on another computer.

## Review Questions

* The Internet protocol suite is a _____ layer model. The Internet protocol suite is a four-layer model.
* The layers of the Internet protocol suite are _____. The layers of the Internet protocol suite are Link, Internet, Transport, and Application.
* The Internet protocol suite is maintained by _____. The Internet protocol suite is maintained by the Internet Engineering Task Force (IETF).
* The Internet protocol suite layer that contains communication technologies for a local network is the _____ layer. The Internet protocol suite layer that contains communication technologies for a local network is the Link layer.
* The Internet protocol suite layer that connects local networks to establish internetworking is the _____ layer. The Internet protocol suite layer that connects local networks to establish internetworking is the Internet layer.
* The Internet protocol suite layer that handles host-to-host communication is the _____ layer. The Internet protocol suite layer that handles host-to-host communication is the transport layer.
* The Internet protocol suite layer that contains all protocols for specific data communications services on a process-to-process level is the _____ layer. The Internet protocol suite layer that contains all protocols for specific data communications services on a process-to-process level is the Application layer.
* A memorandum published by the Internet Engineering Task Force (IETF) describing methods, behaviors, research, or innovations applicable to the working of the Internet and Internet-connected systems is known as a _____. A memorandum published by the Internet Engineering Task Force (IETF) describing methods, behaviors, research, or innovations applicable to the working of the Internet and Internet-connected systems is known as a Request for Comments (RFC).
* A Request for Comments (RFC) which is characterized by a high degree of technical maturity and by a generally held belief that the specified protocol or service provides significant benefit to the Internet community is known as a/an _____. A Request for Comments (RFC) which is characterized by a high degree of technical maturity and by a generally held belief that the specified protocol or service provides significant benefit to the Internet community is known as an Internet Standard.
* A Request for Comments (RFC) that may include official rules, but which does not affect over the wire data and is not on the standards track is known as a/an _____. A Request for Comments (RFC) that may include official rules, but which does not affect over the wire data and is not on the standards track is known as a Best Current Practice.
* The Internet protocol suite protocols are _____ (more/less) rigidly designed into strict layers when compared to the OSI model. The Internet protocol suite protocols are less rigidly designed into strict layers when compared to the OSI model.
* The Internet protocol suite layer that includes the OSI Data Link and Physical layers, as well as parts of OSI's Network layer is the _____ layer. The Internet protocol suite layer that includes the OSI Data Link and Physical layers, as well as parts of OSI's Network layer is the Link layer.
* The Internet protocol suite layer that is a subset of the OSI Network layer is the _____ layer. The Internet protocol suite layer that is a subset of the OSI Network layer is the Internet layer.
* The Internet protocol suite layer that includes the graceful close function of the OSI Session layer as well as the OSI Transport layer is the _____ layer. The Internet protocol suite layer that includes the graceful close function of the OSI Session layer as well as the OSI Transport layer is the Transport layer.
* The Internet protocol suite layer that includes the OSI Application layer, Presentation layer, and most of the Session layer is the _____ layer. The Internet protocol suite layer that includes the OSI Application layer, Presentation layer, and most of the Session layer is the Application layer.

## Assessments

* Lesson Flashcards
* Terms Flashcards
* Quiz

## See Also

* Computer Networks - TCP/IP Model
* Cisco: The TCP/IP Stack