An Analysis Of Wireless Network Computer Science Essay

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A wireless network is any type of network implemented without the use ofwires, carried out with information transport systems by remote control throughthe use of radio waves that resemble the bearer of the signal information. Andthe implementation of this network uses the physical layers of the network.

Local area networks are symbolized by the word LAN. Their primary objectiveis to achieving the desired maximum benefit from resources provided by deviceson the network. They provide many of these networks of services to users,enabling them to communicate with each other through e-mail and access toprograms and applications. In addition, they offer the possibility of access tocommon databases, but this did not prevent the emergence of some obstacles thatlimit the widespread use of these networks. The main obstacles are identifiedas the following:

In addition to the high prevalence of computers, it could be argued that thefeatures provided by the WLAN for laptops and bloggers have led to an increaseddemand for this new technology which will play an important role in ourelectronic future. The world is moving in a new modern era, replacing the wire,which that has been relied upon over past decades, with wireless devices.

IEEE 802.11 is a standard wireless internet network. The original IEEE 802.11standard, which was launched in 1997, has Access Protocol to carrier with acollision avoidance CSMA / CD access mechanism to the carrier, just as in thecase of Ethernet networks. All the amendments to the standard IEEE 802.11 areadopted on the same access mechanism. However, the effectiveness of theProtocol CSMA / CD is very weak, and as a result, sacrifices a great deal ofbandwidth in order to ensure reliable data transmission. These limitationsexist in all techniques based on the protocol CSMA / CD.

IEEE 802.11 standard is also essential for the two-speed transfer of data: 1and 2 megabits per second to send via infrared (IR) or radio waves at anoperating frequency of 2.4 GHz. Despite the absence of any practical applicationuntil now to send via infrared, it is still part of the original standard.

Several product designs appeared on the market in accordance with thespecifications of the original IEEE 802.11 standard, but were soon replacedwith products compatible with standard IEEE 802.11b after the adoption of theamendments to the fundamental criteria in 1999.

IEEE 802.11 standard is known by several names, including: Wi-Fi,Wireless-Fidelity, WLAN, Wireless LAN, and IEEE 802.11x. Let's clarify thisambiguity in the labelling before moving to the various adjustments (versions)to the standard IEEE 802.11.

Using the 802.11b and 802.11g standards for wireless networks, the 2.4 GHzfrequency band is set by the International Telecommunication Union ITU, calledISM (for industrial uses, scientific and medical). It is used, in particular,in the package L-frequency 2400 up to 2483.5 MHz. It uses a standard IEEE802.11a 5 GHz band, which is called the infrastructure of national unlicensedUNII of information, which covers the domain from 5:15 to 5:35 GHz and 5.725 -5.825 GHz.

There has been a sharp rise in the use of the 2.4 GHz band in crowded publicareas as a result of increasing numbers of wireless networks and otherequipment that use the same frequency band, such as wireless phones equippedwith Bluetooth. The 5 GHz bandwidth offers a lower interference ratio, butother problems arise with the nature of this package. The high-frequency radiowaves are more sensitive to the absorption of low-frequency waves. Radio wavesof 5 GHz have a high sensitivity to water and surrounding buildings or other obstaclesas a result of the high absorption rate in this package. This means that thenetworks that operate according to the 802.11a standard are more limited withregard to line consideration, which may require the use of a greater number ofaccess points to cover the same area that could be covered by a wirelessnetwork operating in accordance with standard 802.11b, and the cells resultingfrom the use of access points operate in accordance with standard 802.11a withthe same output power of a smaller space.

Amendments to the criteria: IEEE 802.11

A, B and G amendments are more common in the family of 802.11 standards.Other amendments within the same family also [cf] [hj] concern improvements andupgrades or patches to earlier specifications within this family. Here, we willtake a look at the amendments A, B, G and N.

IEEE 802.11b

This includes standard IEEE 802.11b enhancements for the original 802.11standard to support the transfer of data at greater speeds (5.5 and 11 megabitsper second). This standard uses the same method of access to the carrierspecified in the original 802.11 standard. It uses standard IEEE 802.11btechnology across the spectrum and the allocated DSSS direct sequence is alsodefined in the original standard.

Any of the wireless network cards compatible with standard 802.11btheoretically transfer data at a speed of 11 megabits per second, but it willreduce the speed (on a scale adapted to select data transfer speed) to 5.5, and2, and then to 1 megabit per second in the event of any loss of data packets.The minimum speed for data transfer is less sensitive to interference andfading because it uses a more reliable method for encoding data (i.e. therelationship between signal and noise become even better at lower speeds).

IEEE 802.11a

This standard is used (just as in the standard IEEE 802.111b) with the sameunderlying protocol specified in the original standard. IEEE 802.11a standardoperates in at the 5 GHz bandwidth and uses the modulation technique OFDMorthogonal frequency division, giving it the ability to reach a maximum speedof data transfer equivalent to 54 megabits per second. It can reduce this speedusing natural selection adapted to the speed of data transfer to 48, 36, 24,18, 12, 9 and 6 megabits per second if the need arises.

This has not attained the standard IEEE 802.11a up to this day, butwidespread deployment is achieved by its counterpart IEEE 802.11b. Barriers tothe use of this criterion are: presence of the previous standard IEEE 802.11bon a large scale, double primary products which are designed according to thisstandard, and the most stringent laws in the frequency band 5 GHz.

IEEE 802.11g

This was approved as the third amendment to the 802.11 standard in June 2003and given the name IEEE 802.11g. This criterion (like its counterpart IEEE802.11b) is within the frequency band 2.4 GHz. 802.11g standard uses the sametechnology adopted in the encoding standard 802.11a (OFDM), which can attain amaximum speed of data transfer up to 54 megabits per second. It ensurescompatibility with products operating in accordance with standard 802.11b, dueto the use of cryptographic techniques CCK + DSSS (such as those used in802.11b) data transfer speeds at 11 and 5.5 megabits per second, while usingcoded DBPSK / DQPSK + DSSS at speeds 1 and 2 megabits per second.

IEEE 802.11n

The last modified aim of the 802.11 standard is called IEEE 802.11n and is usedto reach the theoretical maximum speed for data transfer equivalent to 540megabits per second, making it 40 times faster than standard 802.11b and 10times than standard 802.11a. The new standard relies on the same previousamendments to the 802.11 standard with the basic difference being the use ofmultiple input and multiple output (Multiple-Input Multiple-Output MIMO), whichrequire the use of several transmitters and several receivers to increase thespeed of data transfer and transmission range.

Components of wireless networks

Access point

The access point “complex” is wireless. The sender/future wireless hotspotsare connected with each other, which also links with the wired network. Thiscould link a group of access points to each other in a particular order tobuild a great wireless network. The access point from the viewpoint of thewireless users or customers (such as laptop computers or mobile stations)provides a wire to connect the stations for default users. Linking these “wire”radio stations, users connect to each other as these stations link to the wirednetwork.

There is a difference between the access point and wireless routers.Wireless routers are deployed heavily in the market these days. They consist ofthe wireless router access point in addition to the prompt for the network, sothey are able to perform more complex tasks than those carried out by theaccess point. You can think of wireless router as a bridge to the WirelessBridge (connecting the wireless network and wired Ethernet network) which isdirected (by providing the features of Internet Protocol routing packets IPRouting).

The customer has access points after seeing the “names” of these points. Thisis called the method of the definition of ID Services Group Service SetIdentifier (SSID), which must share all members of the selected wirelessnetwork. There should be preparation for all access points and wireless clientswho are within the range of services expanded and one Extended Service Set(ESS) to use the same ID (SSID). To simplify the idea you can consider the SSIDas the “label that defines the Ethernet port”. Any communication with awireless network has a defined SSID (o) which is equivalent to connecting yourPC to a wired network via an Ethernet port on the wall with a label thatdisplays the definition of ‘o'.

Wireless clients Wireless Clients

The customer's wireless network is any radio station that relates to awireless LAN to share resources. Wireless stations are defined as any computerhas a wireless network card to send and receive the radio signals RF. Users ofthe wireless network include: common laptop computers, handheld computingdevices (PDAs), surveillance equipment, wireless phones and voiceover InternetProtocol VoIP Wireless.

It must be pointed out that the network structure may not reflect thesepatterns directly and consistently. For example, it may act as a wireless linkbetween two points (Point-to-Point) in a style or a pattern of infrastructure,as you can find a network with stars that are based particularly on relying onthe links. The pattern of the wireless network is one of the basic settings ofthe wireless network card, and not just one of the properties of the structureinfrastructure as a whole.

The style for the Ad hoc Mode (IBSS)

The pattern of the sector (also known as the pattern of Peer-to-Peer) is away to directly link wireless clients. Allowing customers to link to thewireless network and work within the style eliminates the need to use anyaccess points centrally; this way, all points within a network of privatewireless communication link directly with the other points.

All wireless network cards for all our customers in the wireless networkshould be prepared to work within its own style and use the same service setidentifier SSID and “Channel Number”.

Wireless networks consist typically of a small group of devices positioned neareach other. This decreases the performance of the wireless network whenever thenumber of points is located within it. As a result, a link to the wirelessnetwork or wired LAN is needed to the internet portal dedicated to thepreparation of this purpose.

The words “Ad hoc” are Latin for “for this purpose”, but they are often usedto express solutions or improvised events. IEEE 802.11 standards use the term(Independent Basic Service Set IBSS) to refer to a particular brand of wirelessnetworks.

The pattern of infrastructure Mode (BSS)

Networks operating within the pattern of an infrastructure, unlike theprivate networks that do not contain a central element, contain the element oftask of coordination: an access point or central station. Customers can accessthe wireless network and the wired network through the access point if thispoint connected to a wired network.

The network contains several access points and the customers should beprepared to use the same identifier SSID. If you want to make sure that yourwireless network is able to operate at maximum capacity you should not prepareall the access points located within the same physical location to use the samechannel. Clients can discover (via scan a range of frequencies) the channelused by the access point and therefore there is no need for the customer toknow the channel number in advance.

IEEE802.11 standards are used (Basic Service Set BSS) to refer to the patternof infrastructure for wireless networks.

Case 1: Network stars

The star topology is the most common wireless infrastructure; a structureusually adopted in patches of Hot Spot wireless coverage, whether found in theairport or within the centre to access the remote. Internet Service Providersuse the wireless infrastructure in stats (and to connect all points to a numberof points). Often this type of network expands the structure or tree to combinethem with other forms of wireless networks.

Case 2: Access points

The access points (Point-to-Point) are considered one of the basic elementsof the infrastructure of the wireless network. These links can be found at thelevel of the structure of the wireless network as part of a network with stars;a simple interface between two points or within any other structure. This canoperate the link between two points within the pattern or style ofinfrastructure.

Case 3: Repeating

The need for redundancy must be highlighted in case of obstacles in the lineof sight, or when the distance is too long and cannot be covered. The complexwired networks are equivalent to the repetition in wireless networks. Thefrequency setting depends largely on the standards of equipment and softwareused, which makes characterization in general difficult.

Units may consist of repetitions of a physicist and one or two may alsocontain one or two radio transmitters. This can also be seen as unit iteration,and the future of customer access points and repeaters. The SSID is usually thesame for all three of these units. This is often associated with unit repetitionin addition to a physical ID SSID.

What is the security of information?

So that we can understand the concept of information security it isnecessary to review the historical context of the evolution of this concept.Until the late seventies this was known as Communications Security (COMSEC) anddefined by the recommendations of the security of information systems andcommunications to the National Security Agency in the United States, includingthe following:

standards and procedures taken to prevent access to information by unauthorizedpersons through communication and to ensure the authenticity of thesecommunications. This included specific activities within the security ofcommunications COMSEC which are four parts: Crypto security, TransmissionSecurity, Emission Security and Physical Security. Also, the definition ofsecurity of communications is related to two properties which are the subjectmatter of this unit: confidentiality and verification of identity.


This ensure that information does not reach people, processes or devicesnot authorized to access to the information (protection from unauthorizeddisclosure of information).

Identity check

This is a security measure to ensure the validity of the call, the messagesource, or a way to verify the validity of a person receiving information of aspecific classification (or verification of the source of this information).This began in the eighties with the steady growth of the personal computer andstarted a new era of security. Computer security (COMPUSEC) was identified bythe recommendations of the security of information systems and communicationsto the National Security Agency in the United States, and included thefollowing: standards and procedures that ensure the confidentiality, integrityand availability of information system components, including equipment,software, embedded software and firmware, information processed, stored and transported.This guarantees the security of computers' additional personal properties thatrelate to the subject of this unit: perfection and availability.


This reflects the quality of any information system for the validity andreliability of the operating system, the logical integration of equipment andsoftware mechanisms that provide protection, and the harmony of builtinformation with the stored data.


This covers the reliable access to data and information services whenneeded by authorized persons. In the nineties, the concepts of securityintegrated (communications security and computer security) to form what becameknown as Security Information Systems (Information Systems Security - INFOSEC).The concept of the security of information systems for the four properties hasalready been defined within the concepts of the security of communications andcomputer security: confidentiality, authentication, completeness, availability,and new added property: the fight against denial.

Against denial (liability)

Assertion that the sender has obtained the data to prove the arrival of datato the consignee and that the future has received proof of identity of thesender, which prevents the possibility of denial of any of the parties that haddealt with this data.

Information security and wirelessnetworks

The recommendations from the security of information systems andcommunications to the National Security Agency in the United States are asfollows: the protection of information systems against unauthorized access toor alteration of the information during the preservation, processing,transport, and against the shutdown of service for authorized users or theprovision of service to unauthorized persons, including all the necessary measuresto detect, document and address these threats.

The application of security features

The reference model OSI Open Systems Interconnect was invented by theInternational Standards Organization ISO characterization theory for the designof network protocols (communications) software. This model and the variouscommunication functions are divided into seven different layers and workindependently of each other.The design follows the protocols according to themodel OSI and the principle of “Stack”. The use of a model of protocolsoperating according to the principle of classes or Stack means that each layerwill use the functions of the lower class only, while the catering class isimmediately above it. This is reflected in the design method according to theprinciple of being layered directly to implement security features.

General observations on the linklevel encryption

A link level encryption mechanism for secure data as it travels between twopoints connected by the same physical link provides link level encryption toprotect data protocols or hackers passing through the physical link.

This requires an encryption key to provide a specific or shared secretbetween the parties that will participate in the encryption process, inaddition to the agreement of a joint algorithm for encryption. In the absenceof transmitter and receiver sharing, the same physical carrier should decryptthe data and re-encrypt at each transit point during the transition to thefuture. Encryptions on the link level are usually due to the absence ofencryptions on the higher levels.

Confidentiality of wireless networks

Should you use an algorithm equivalent of the secret WEP wireless network ornot? We will need a secret wireless network to ensure that the information sentbetween the access points and PC users will not be seen by unauthorizedpersons. Must ensure that the confidentiality of wireless networks that theongoing contacts between a group of access points within the distributionsystem for wireless Wireless Distribution System (WDS) or between the accesspoint AP and a computer connected to the STA will remain protected.

The concept of confidentiality of the wireless network has been associatedwith the term “confidential equivalent wired network WEP”. WEP formed part ofthe basic IEEE 802.11 standard for wireless networks in 1999.

The main objective of confidentiality equivalent to the wired network is aWEP secured wireless network with a similar level of secrecy, because secrecyis available in wired networks. The need for this protocol is clear: wirelessnetworks use radio waves and therefore are more vulnerable to prying eyes.

It was the age equivalent of the secret protocol wireless network WEP whichwas too short, had a poor design and was non-transparent regarding the successof many of the attacks that penetrate networks using this protocol. It tookonly a few months until the protocol had been breached. Although the length ofthe encryption keys was limited by certain laws of the export ban, that thisprotocol has proved its weakness, regardless of the length of the encryptionkeys used.

The design flaws were not the only reason for the failure of the secretprotocol equivalent of the wireless network WEP. The lack of a system for themanagement of cryptographic keys within the same protocol also contributed tothe abort. It did not contain the equivalent of the secret protocol wirelessnetwork WEP in any system for the management of cryptographic keys, and theonly way to distribute encryption keys required the preparation/entry of thesekeys manually in each of the wireless equipment (except that the shared secretbetween several people was no longer a secret!).

Enter the secret protocol to the equivalent of the wireless network WEP numberof amendments to some of the producers of wireless equipment but theseamendments did not live up to the level required for the success of theprotocol (some examples include the protocol WEP + company Lucent and theProtocol WEP2 company Cisco).

The death of the secret protocol equivalent of the wireless network WEP and thebirth of the Protocols Protected Access wireless network WPA and WPA2

After the death of the secret protocol equivalent of the wireless networkWEP, a new protocol was proposed: Protected Access WPA wireless network. It wasadopted in 2003 as part of the standard IEEE 802.11i wireless networking, andin 2004 under the name WPA2. It has been designed with WPA and WPA2 protocolsto work with or without a server to manage the encryption keys. In the absence ofa key management server, all stations will use a “pre-shared encryption key”(PSK). This type of operation is known as the protocol WPA or WPA2 Personal.

You can use the WPA2 protocol server keys for the encryption of the WPAInstitutional Protocol. WPA2 protocol requires the existence of institutionalserver running IEEE 802.1X standards for the distribution of encryption keys.The most important developments are included in the WPA2 protocol compared toits predecessor. WEP offers the possibility of exchanging encryption keysdynamically by integrating temporary protocol encryption keys, known as theTemporal Key Integrity Protocol (TKIP).

Identity verification in wirelessnetworks

The verification of identity is defined in the context of wireless networkprocedures aimed at ensuring the viability of communication between the accesspoints and/or wireless stations. The verification of identity in wirelessnetworks can be expressed more simply as the right to send data to and throughthe wireless network.

To understand the concept of identity verification in wireless networks itis essential to understand what happens when you start a communication sessionbetween the access point and/or radio station. It initiates the connection,which is a process called “linkage Association”. Mechanisms have been added tothe process of “linkage” in the design of the IEEE 802.11b standard forwireless networks:

The verification of identity implies the absence of any security mechanism,which can be any person communicating with the access point. The access pointin the verification of identity uses the shared key (a password) with thestation user/access point. It provides a mechanism to respond to the challengerequested by the access point to verify that the user knows the shared secretand thus is allowed to access the wireless network.