The OSI Reference Model

The OSI model provides an extensive list of functions and services that can occur at each layer. It also describes the interaction of each layer with the layers directly above and below. The TCP/IP protocols discussed in this course are structured around both the OSI and TCP/IP models. Click each layer of the OSI model to view the details. The functionality of each layer and the relationship between layers will become more evident throughout this course as the protocols are discussed in more detail. Note: Whereas the TCP/IP model layers are referred to only by name,...

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Lab - Researching Networking Standards

In this lab, you will complete the following objectives: Part 1: Research Networking Standards Organizations Part 2: Reflect on Internet and Computer Networking Experience Lab - Researching Networking Standards ...

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Internet Standards

Standards organizations are usually vendor-neutral, non-profit institutions established to develop and promote the concept of open standards. Various organizations have different responsibilities for promoting and creating standards for the TCP/IP protocol. Standards organizations shown in Figure 1 include: Internet Society (ISOC) – Responsible for promoting the open development and evolution of Internet use throughout the world. Internet Architecture Board (IAB) - Responsible for the overall management and development of Internet standards. ...

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TCP/IP Protocol Suite

Today, the TCP/IP protocol suite includes many protocols, as shown in the figure. Click each protocol to view the acronym’s translation and description. The individual protocols are organized in layers using the TCP/IP protocol model: Application, Transport, Internet, and Network Access Layers. TCP/IP protocols are specific to the Application, Transport, and Internet layers. The network access layer protocols are responsible for delivering the IP packet over the physical medium. These lower layer protocols are developed by various standards organizations. The TCP/IP protocol suite is implemented as...

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Development of TCP/IP

The first packet switching network and predecessor to today’s Internet was the Advanced Research Projects Agency Network (ARPANET), which came to life in 1969 by connecting mainframe computers at four locations. ARPANET was funded by the U.S. Department of Defense for use by universities and research laboratories. Click through the timeline in the figure to see details about the development of other network protocols and application...

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Protocol Interaction

Communication between a web server and web client is an example of an interaction between several protocols. The protocols shown in the figure include: HTTP - is an application protocol that governs the way a web server and a web client interact. HTTP defines the content and formatting of the requests and responses that are exchanged between the client and server. Both the client and the web server software implement HTTP as part of the application. HTTP relies on other protocols to govern how the messages are transported between the client and server. TCP - is the transport...

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Rules that Govern Communications

A group of inter-related protocols necessary to perform a communication function is called a protocol suite. Protocol suites are implemented by hosts and networking devices in software, hardware or both. One of the best ways to visualize how the protocols within a suite interact is to view the interaction as a stack. A protocol stack shows how the individual protocols within a suite are implemented. The protocols are viewed in terms of layers, with each higher level service depending on the functionality defined by the protocols shown in the lower levels. The lower layers of the stack are concerned...

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Message Timing

These are the rules of engagement for message timing. Access Method Access method determines when someone is able to send a message. If two people talk at the same time, a collision of information occurs and it is necessary for the two to back off and start again, as shown in Figure 1. Likewise, it is necessary for computers to define an access method. Hosts on a network need an access method to know when to begin sending messages and how to respond when collisions occur. Flow Control Timing...

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Message Size

Another rule of communication is size. When people communicate with each other, the messages that they send are usually broken into smaller parts or sentences. These sentences are limited in size to what the receiving person can process at one time, as shown in Figure 1. An individual conversation may be made up of many smaller sentences to ensure that each part of the message is received and understood. Imagine what it would be like to read this course if it all appeared as one long sentence; it would not be easy to read and comprehend. Likewise, when a long message is sent from one host to another...

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Rule Establishment

Before communicating with one another, individuals must use established rules or agreements to govern the conversation. For example, consider Figure 1, protocols are necessary for effective communication. These rules, or protocols, must be followed in order for the message to be successfully delivered and understood. Protocols must account for the following requirements: An identified sender and receiver Common language and grammar Speed and timing of delivery Confirmation or acknowledgment requirements ...

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Communication Fundamentals

A network can be as complex as devices connected across the Internet, or as simple as two computers directly connected to one another with a single cable, and anything in-between. Networks can vary in size, shape, and function. However, simply having a wired or wireless physical connection between end devices is not enough to enable communication. For communication to occur, devices must know “how” to communicate. People exchange ideas using many different communication methods. However, regardless of the method chosen, all communication methods have three elements in common. The first of these elements is the message source, or...

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Chapter 2: Configure a Network Operating System

Cisco IOS is a term that encompasses a number of different operating systems, which runs on various networking devices. The technician can enter commands to configure, or program, the device to perform various networking functions. Cisco IOS routers and switches perform functions that network professionals depend upon to make their networks operate as expected. The services provided by the Cisco IOS are accessed using a command-line interface (CLI), which is accessed by either the console port, the AUX port, or through SSH or Telnet. After connected to the CLI, network technicians can make configuration...

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