Networks and Connecting Devices

The Network
Because Wal-Mart is a globally recognized company the use of satellite communication system from Hughes Network Systems is essential. Since the implementation off satellite communication Wal-Mart has installed the system throughout their stores across the nation. The benefits of this communication system was to make credit authorizations faster, and to also have a much faster communication from one store to another, Wal-Mart’s headquarters and among all other facilities.


Interface
For large commercial functions such as Wal-Mart, their IT department has decided to use an Ethernet card. An Ethernet card is the most common type of network interface card, the card runs to a hub or switch, which allows you to use cables with different wiring called a crossover cable to plug directly into another computer or printer.


Media
Communications media are the paths, or physical channels, in a network over which information travels. All types of communication media are either wired or wireless. Wired communications media transmit information over a closed, connected path. Wireless communications media transmit information through the air. The forms of wired and wireless communications media include:

Wired
Twisted-Pair Cable
Coaxial Cable
Optical Fiber

Wireless
Infrared
Microwave
Satellite

Wal-Mart operates under a wireless network communincation because it is extremely feasible for telecommunication across great distances and very convienent when one or more parties may be in motion.


Software
Like large compnaies Wal-Mart uses both types of communications media in their stores to transmit communication and radio waves in order to connect network hardware devices. Communications media transport information through paths or physical channels in a network to computers and the connecting devics. Each computer is programmed with the software that supports the movement of information. The software is either modem software / or a network operating system.


Connecting devices/ Components
The main responsibility for a network is that it is able to connect a computer on the network acting as a switchboard for information intergration. Wal-Mart’s systems are connected by Novell LAN and they also provide productivity service for Wal-Mart.




Speed of the Internet
Wal-Mart uses frame relay on their DS3 network that runs at 44.736 Mbps. Frame Relay is a service that can be set up over high speed lines such a DS3 to create virtual circuits connecting multiple offices.
The virtual circuits provides network connections individual offices to one another without having to run physical lines. Wal-Mart has deployed their lastest project called the Vendor Frame Network, which connects about 20 of Wal-Mart’s largest suppliers to its frame via PVC connection.


Voice over IP?
Unlike traditional types of comminication which were originally developed to transmit voice telephone calls. (VoIP) allows you to send voice communications over the Internet and avoid the toll charges that you would normally receive from your long distance carrier. It is a means of transmitting a voice telephone call over a computer data network. Wal-Mart integrated wireless (VoIP) systems that use an IP network backbone.


Four areas of Network Security
The four principles areas of network security are confidentiality, authenticity, integrity, and availability.
Confidentiality means that information can be obtained only by those authorized to access it, whihc can be summarized as keeping secrets a secret. Wal-Mart has adopted a technology called Secure Sockets Layer (SSL), which encrypts sensitive information before it is sent over the Internet.
Authenticity means that information really comes from the source it claims to come from. It is important to be aware of authenticity of important documents such as military orders, medical disgnoses, and directions to a stockbroker.
Integrity means that information has not been altered, much like authenticity. Wal-Mart has created fire walls to help protect threats to integrity like network transmissions and unsolicited Web servers that allow thier content to be relaced. Availability is a service or resource that is available when its supposed to be. In order for Wal-Mart to reach orders to its customers on time they have an IDS which watches network traffic for intrusion attempts.

Domain Name
walmart.com