II. MEDIA ACCESS TECHNIQUES
Generally speaking, typical scenario of communications networks interaction consists in a bunch of devices trying to communicate with each other by using the same medium. Home wireless networks, cellular networks, Ethernet environments are only a few examples of this setting.
Sharing a medium requires specific procedures or agreements among all network users in order to set rules for effective and efficient communication, these procedures are the so called Media Access Control Protocols. They dictate important aspects of the interaction, some of them are presented as follows:
When and how long can a device access a medium.
How can a device determine weather the communication succeeded or not.
How does a device deal with problems (access conflicts, security issues, etc). [*Data communications and networking, Forouzan, Fifth edition page 326]
Nowadays there are multiple MAC protocols that serves different network approaches and topologies, it is clear that for instance an Ethernet TCP/IP network that is packet based, wired and so forth should have a different sharing medium technique than a 2G voice network that uses free air as communication interface and is mainly voice oriented. Any MAC protocol in general should pursuit some basic guidelines in terms of structure and performance but implementation may be different depending on the network setting and application.
A broad break down of MAC protocols is presented as follows:
Random access:
ALOHA
CSMA (Carrier sense media access)
CSMA/CD (Carrier sense media access with collision detection)
CSMA/CA (Carrier sense media access with collision avoidance)
Controlled access:
POLLING
TOKEN PASSING
Channelization:
TDMA (Time division media access)
FDMA (...
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...ium access selected technique. It also uses FDD carriers and was first developed for 900 MHz (GSM 900) band but then extended to 1800 MHz band (GSM 1800). GSM was originally designed as a voice oriented network but later on some new features have been aggregated to support data transmission. General Packet Radio Services (GPRS) and Enhanced Data-rates for Global Evolution (EDGE) showed up accordingly to fulfill market demands in terms of voice reliability and high transmission data rates. As of today GSM is still dominant in current mobile communication market, it has 70% of market share (wikipedia reference) despite new upcoming technologies such as LTE taking prominence these days.
IV. CODE DIVISION MEDIA ACCESS
CDMA is a multiple access technique that allows multiple users to access a medium by assigning each user a unique key also known as spreading code.
In this section we investigate attacks and threats to our primary devices. These attacks and threats are built off of the vulnerabilities the previous section and help to determine which security controls would be most valuable against future attacks.
...rly in the 90s. Eventually, it increased its speed and added more functionality like General Packet Radio System (GPRS) to the system which enhanced it to 2.5G status. 2.5G has data rates up to about 144kbit/s. It typically uses a variation of Time Division Multiple Access (TDMA).
User Communications. Dartmouth College, Department of Computing Services. "Computer and Network Policy." BlitzMail Bulletin. Wed, 15 Nov 2000 13:36:45.
Access (WiMax) is very important to Motorola. WiMax is an Institute of Electrical and Electronics Engineers (IEEE) standard designated 802.16e-2005 (mobile wire-less). With WiMax cell phones will no longer be tied to cellular networks. WiMax has the potential to replace a number of existing telecommunications infrastructures (WiMax, 2007).
Roberts, Richard M. "Network Secrurity." Networking Fundamentals. 2nd ed. Tinley Park, IL: Goodheart-Willcox, 2005. 599-639. Print.
Peer-to-peer is a communications model in which each party has the same capabilities and either party can initiate a communication session. Other models with which it might be contrasted include the client/server model and the master/slave model. In some cases, peer-to-peer communications is implemented by giving each communication node both server and client capabilities. In recent usage, peer-to-peer has come to describe applications in which users can use the Internet to exchange files with each other directly or through a mediating server.
Due to the sensitive and confidential information that would exist on such devices, it is imperative that security solutions and processes are implemented in order to protect and secure such content from the proliferation of threats and vulnerabilities which can affect mobile devices (Juniper Networks, n.d.).
Networks are designed in a number of ways, based on the geographical area, the technology used, user group specific, application based etc. But we can roughly categorize the communication networks in 2 broad categories, based on transmission: Connection-Oriented and Connectionless.
Print. The. Gordon A. Gow, and Richard K. Smith. Mobile and wireless communications: an introduction, McGraw-Hill International, 2006. Print.
The world has gone through a lot of changed as time passes by. With advancements in the technological field people are can communicate with ones from around the world without having to even lift a finger. To make things more efficient and more cost saving industries have made technology wireless. Wireless technology gives people the chance to get up from their stationary computer, or cord phone and able to freely move without restrictions. The IT, or Information Technology has become a standard and very critical part of today’s society. Wireless technology came from the basic just cellular usage to sensors in the medical field. Wires are now a thing of the past in today’s world with forever revitalizing technology.
G in 1G, 2G, 3G and 4G stands for the “Generation” of the mobile network. Today, mobile operators have started offering 4G services a higher number before the ‘G’ means more power to send out and receive more information and therefore the ability to achieve a higher efficiency through the wireless network. During the time of 1G, radio signals were transmitted in ‘Analogue’ form. 2G networks on the other hand, were based on narrow band digital networks. The 3rd generation of mobile networks has become popular and users access the Internet over devices like mobiles and tablets. This means a 3G network actually allows for more data transmission and therefore the network enables voice and video calling, file transmission, internet surfing, online TV, view high definition videos, play games and much more. 4th Generation mobile networks are believed to provide many value added features.
ErrealMedia (2010) Network standards OSI Reference Model; History of OSI Model; OSI Layers in Action http://www.erealmedia.com/cms125/
Various Applications: It is most utilized for sending email, voice calling , web browsing, SMS etc..
One of the latest advancements in wireless data. It is used in GSM (Global System for Mobile Communications) for transferring data in packets.
Communication - Audio, Streaming Audio, Computer-based telephony, Computer based Audio conferencing, Video conferencing, and streaming video.