What are the 5 aspects of the information network we will focus on in this course?
1-Devices that make up the network
2-Media that connect the devices
3-Messages that are carried across the network
4-Rules and processes that govern network communications
5-Tools and commands for constructing and maintaining networks
What is the definition of the term network for this course?
data or information networks capable of carrying many different types of communications, including traditional computer data, interactive voice, video, and entertainment products.
What would happen to the network if a message was sent as one massive continuous stream of bits?
no other device would be able to send or receive messages on the same network while this data transfer was in progress
What are the 2 advantages of segmentation?
many different conversations can be interleaved on the network segmentation can increase the reliability of network communications
What is multiplexing?
process used to interleave the pieces of separate conversations together on the network
What are end devices on a network?
Computers (work stations, laptops, file servers, web servers)
Mobile handheld devices (such as wireless barcode scanners, PDAs)
What is the definition of a host?
either the source or destination of a message transmitted over the network
What is the definition of a server?
hosts that have software installed that enables them to provide information and services
What is the definition of a client?
hosts that have software installed that enables them to request and display the information obtained from the server
List examples of intermediary devices.
-wireless access points)
-Internetworking Devices (routers)
-Communication Servers and Modems
-Security Devices (firewalls)
List examples of process that intermediary devices perform.
Regenerate and retransmit data signals
Maintain information about what pathways exist through the network and internetwork
Notify other devices of errors and communication failures Direct data along alternate pathways when there is a link failure
Classify and direct messages according to
Permit or deny the flow of data, based on
What are the 3 primary types of media used in modern networks?
Metallic wires within cables
Glass or plastic fibers (fiber optic cable)
What criteria should be used to select network media?
The distance the media can successfully carry a signal. The environment in which the media is to be installed.
The amount of data and the speed at which it must be transmitted.
The cost of the media and installation
What are the ways in which network infrastructure can vary?
The size of the area covered
The number of users connected
The number and types of services available
What is the definition of a LAN?
individual network usually spans a single geographical area, providing services and applications to people within a common organizational structure
What is an Internetwork?
A global mesh of interconnected networks (internetworks) meets these human communication needs.
What is an Intranetwork?
a private connection of LANs and WANs that belongs to an organization, and is designed to be accessible only by the organization's members, employees, or others with authorization
Define a physical port
A connector or outlet on a networking device where the media is connected to a host or other networking device.
Define an interface
Specialized ports on an internetworking device that connect to individual networks.
What process do networking layer protocol suites describe?
The format or structure of the message The process by which networking devices share information about pathways with other networks How and when error and system messages are passed between devices The setup and termination of data transfer sessions
What is proprietary?
one company or vendor controls the definition of the protocol and how it functions
What does the use of standards and protocols provide?
products from different manufacturers can work together for efficient communications
What is an application protocol?
defines the content and formatting of the requests and responses exchanged between the client and server
What is a Transport Protocol?
manages the individual conversations between web servers and web clients
What is the Internetwork Protocol
responsible for taking the formatted segments from TCP, encapsulating them into packets, assigning the appropriate addresses, and selecting the best path to the destination host.
What is the Network Access Protocol?
Network access protocols describe two primary functions, data link management and the physical transmission of data on the media.
What are the benefits of using a layered model to describe networking?
-Assists in protocol design, because protocols that operate at a specific layer have defined information that they act upon and a defined interface to the layers above and below.
-Fosters competition because products from different vendors can work together.
-Prevents technology or capability changes in one layer from affecting other layers above and below.
-Provides a common language to describe networking functions and capabilities.
What is done at the Application Layer?
Represents the data to the user plus encoding and dialog control
What is done at the Transport Layer?
Supports communication between diverse devices across diverse neworks
What is done at the Network Access Layer?
Controls the hardware devices and media that make up the network
What are the seven steps in a complete communication process?
1. Creation of data at the application layer of the originating source end device
2. Segmentation and encapsulation of data as it passes down the protocol stack in the source end device
3. Generation of the data onto the media at the network access layer of the stack
4. Transportation of the data through the internetwork, which consists of media and any intermediary devices
5. Reception of the data at the network access layer of the destination end device
6. Decapsulation and reassembly of the data as it passes up the stack in the destination device
7. Passing this data to the destination application at the Application layer of the destination end device
What are the seven layers of the OSI Model?
Application, Presentation, Session, Transport, Network, Data Link, Physical
Model parallel with the TCP/IP Model?
Data Link, Physical-Network Access
What happens after the frame has reached its' destination?
the Layer 2 address information is removed as the data is decapsulated and moved up the protocol stack to Layer 3
What are layer 3 devices primarily designed for?
to move data from one local network to another local network within an internetwork
What does a router do?
use the network identifier portion of this address to determine which path to use to reach the destination host
What happens when the frame reaches the end device?
the frame and packet headers are removed and the data moved up to Layer 4
What does the information in the frame provide at Layer 4?
identifies the specific process or service running on the destination host device that will act on the data being delivered