Nowadays most Desktop based softwares, operating system (OS) and applications features are being adapted to Smartphones (SMPs). The simplicity and mobility of SMPs are some of the qualities which make them interesting to run different network applications. In order to develop mobile applications with efficient functionality and competitive in marketability, application developers need to have knowledge on network performance of SMPs. In this thesis, an experimental based methodology is provided to evaluate the effect of transmission patterns on One Way Delay (OWD), throughput and packet loss across designed setup for different SMPs. Based on these metrics the SMPs have been compared with each other under the same experimental setting with relatively higher accuracy of measurement techniques. For accurate measurement DAG 3.6E card together with GPS for synchronization is used to capture traffic for further analysis. To avoid undeterministic inputs in the network, the experiment is made to be in a controlled and continuously monitored wireless local area network. Moreover the nodes or sub networks constituting the entire network are evaluated to conceive the effects on the estimated output. From this work application developers will have the opportunity to design their application according to the network performance of SMPs and users are also able to select suitable applications and SMPs.

Which security holes and security methods do IEEE 802.11b and Bluetooth offer? Which standard provides best security methods for companies? These are two interesting questions that this thesis will be about. The purpose is to give companies more information of the security aspects that come with using WLANs. An introduction to the subject of WLAN is presented in order to give an overview before the description of the two WLAN standards; IEEE 802.11b and Bluetooth. The thesis will give an overview of how IEEE 802.11b and Bluetooth works, a in depth description about the security issues of the two standards will be presented, security methods available for companies, the security flaws and what can be done in order to create a secure WLAN are all important aspects to this thesis. In order to give a guidance of which WLAN standard to choose, a comparison of the two standards with the security issues in mind, from a company's point of view is described. We will present our conclusion which entails a recommendation to companies to use Bluetooth over IEEE 802.11b, since it offers better security methods.

Användningen av trådlöst nätverk blev under början av 2000-talet mycket populärt bland privatpersoner, genom dess mobila fördelar, Tekniken medförde många fördelar, men också många nackdelar och frågan var hur många som verkligen hade blivit uppmärksammade på eller kände till dessa och därefter valt att skydda sina trådlösa nätverk. Det främsta syftet med denna uppsats var därmed att undersöka på vilken nivå säkerhetsmedvetandet låg i samhället vid användning av trådlöst nätverk vid gällande tidpunkt. Vidare handlade det också om att reda ut gällande rättsläge , vid handlingar mot eller via ett trådlöst nätverk, och mäta hur utbredd säkerhetsanvändningen var bland trådlösa hemmanätverk. För att besvara detta utgick vi från ett positivistiskt och deduktivt synsätt, med kvalitativa intervjuer för att reda ut gällande rättsläge, pejling av trådlöst nätverk för att mäta säkerhetsläget och kvantitativa enkätintervjuer, för att få fram typer av säkerhetsmedvetande, bland användare av trådlöst hemmanätverk. Innehållet i alla intervjuer baserades på fastställd fakta kring trådlöst nätverk, risker med tekniken, riskförebyggande säkerhetsrutiner och Svensk lag. Vi konstaterade slutligen att gällande rättsläge för närvarande var föråldrat och inte anpassat att hantera de risker som trådlöst nätverk hade medfört. Vidare visade resultatet på ökad säkerhetsanvändning bland trådlösa nätverk i samhället, och att det överlag var yngre användare som stod för denna ökning. Yngre användare visade sig även överlag ha ett högre säkerhetsmedvetande, än äldre, och då särskilt hög teknisk kunskap / The usage of Wireless local area networks (WLAN) became very popular amongst private citizens, during the beginning of the 21 century, because of its mobile advantages. The technology brought many advantages, but also many disadvantages and the question was how many had noticed or knew that these existed and afterwards had chosen to secure their WLAN. The main purpose of this thesis was to examine the current level of security awareness, in the community, when using WLAN. Other goals were to investigate the current general legal context, about actions against or through a WLAN, and measure the widespread usage of security within WLAN. To answer this we used a positivistic and deductive approach, with qualitative interviews to sort out the current general legal context, Wardriving to find and measure the current state of security within WLAN's and quantitative questionnaires to find out the most common types of security awareness amongst users of WLAN. The content of all this was based on facts about the WLAN technology, the risks that comes with it, risk preventing security routines and the Swedish law. Finally we established that the current general legal context was out-of-date and not adapted to handle the new risks that WLAN had brought. Further on the result also showed a increased usage of security amongst WLAN in the community and that the main reason for this was the younger WLAN owners. Younger users also turned out to have higher security awareness, than older users, and particularly very high technical knowledge.

In wireless sensor networks, communications are usually destroyed by signal attenuation, multipath fading and different kinds of interferences like WLAN and microwave oven interference. In order to build a stable wireless communication system, reactions like retransmission mechanisms are necessary. Since the way we must react to interference is different from the way we react to multipathfading and attenuation, the retransmission mechanism should be adjusted in different ways under those different cicumstances. Under this condition, channel diagnostics for discriminating the causes that corrupt the packets between multipath fading and attenuation (MFA) and WLAN interference are imperative. This paper presents a frame bit error rate (F-BER) regulated algorithm based on a joint RSSI-LQI classifier that may correctly diagnose the channel status. This discriminator is implemented on MicaZ sensor devices equipped with CC2420 transceivers. This discriminator is able to improve the accuracy to 91%. Although we need to wait for 2 or 3 necessary packets to make a decision, higher stability and reliability are presented when operating this discriminator.

In computer networking, failures, such as breaking equipment, cable cuts, power failures and human errors continuously cause communication interruptions. Such failures may result in dissatisfied customers, loss of product reputation, violation of SLAs and even critical failures in industrial systems. SDN, which logically centralizes the control plane, is an emerging technology in computer networking. The global view provided by the SDN controller can be used to reconfigure the network in case of a link failure. However, this reconfiguration may take too long for high availability networks. With the introduction of proactive link repair, backup paths are preinstalled in the forwarding devices, reducing path recovery time. This thesis addresses the usage of SDN to provide resiliency in high availability networks. First, we consider how SDN can be used for increasing the reliability of ICNs. Second, we investigate how similar technologies could be applied to deal with fast channel attenuation and resulting outage in mmWave backhaul networks. Finally, we look at CloudMAC-based Wireless LAN, and how SDN-enabled QoS improvements could improve connection reliability. / In computer networking, failures, such as breaking equipment, cable cuts, power failures and human errors continuously cause communication interruptions. Such failures may result in dissatisfied customers, loss of product reputation, violation of Service Level Agreements and even critical failures in industrial systems. Recently, the concept of Software Defined Networking (SDN) was introduced. SDN opens up and centralizes the control plane, which allows designing networks more resilient to failures. In this thesis, we address the usage of SDN in order to provide resiliency in high availability networks. First, we consider how SDN enabled, proactive failure recovery can be used to provide the reliability required in Industrial Control Networks (ICNs). We also investigate how the same approach could be applied to mmWave backhaul networks to cope with fast channel attenuation and the resulting outage. Through extensive experiments, we can demonstrate an increase in reliability for both ICNs and mmWave backhaul networks. Second, we look at CloudMAC-based Wireless LAN, and how SDN-enabled traffic control algorithms could improve connection reliability. Through our experiments we can show that both discriminatory and non-discriminatory algorithms significantly increase the connection reliability. In combination, these results serve to strengthen the image of SDN as a provider of resilient, high-availability networks.

Telecommunications is converging on the use of IP based networks. Due to the low cost of VoIP applications, they are being increasingly used instead of conventional telephony services. IEEE802.11 WLANs are already widely used both commercially and domestically. VoIP applications will also expand from usage over wired networks to voice communications over IEEE802.11 WLANs. This is known as VoWLAN. The use of VoWLAN may reach the maximum capacity of a wireless channel if there are many simultaneous VoIP calls operating close to each other. There is much published research based on a single IEEE802.11 infrastructure WLAN concluding that packet loss, transmission efficiency and latency issues are the major challenges limiting the VoWLAN capacity. The VoIP service quality will drop sharply when the demands exceed the WLAN’s capacity. This thesis demonstrates that these challenges also apply to distributed WLANs. To extend these findings from the existing research, the analysis in this thesis indicates that the capacity of a single IEEE802.11 WLAN channel is 12 VoIP calls. When the number of simultaneous VoIP calls is within the capacity, the WLAN can deliver more than 90% of the voice packets to the receiver within 150 ms (the lowest network performance for supporting acceptable VoIP service). However, as soon as the traffic loads are beyond the wireless channel capacity e.g. the number of simultaneous VoIP calls is greater than 13, the VoIP service quality catastrophically collapses. When the capacity is exceeded there are almost no voice packets that can be delivered to the receiver within 150 ms. Our research results indicate that the delay accumulation for voice packets in the transmitter’s outgoing buffer causes this problem. Our research also found that dropping ‘stale’ voice packets that are already late for delivery to the receiver can give more transmission opportunities to those voice packets that may still be delivered in time. This thesis presents a new strategy called Active Cleaning Queue (ACQ) which actively drops ‘stale’ voice packets from the outgoing buffer and prevents the accumulation of delay in congested conditions. When ACQ is applied in a saturated wireless channel the network performance for supporting VoIP traffic was found to gradually decrease proportional to the numbers of simultaneous VoIP calls rather than catastrophically collapse. There is also published research suggesting that the aggregation of packets can improve the efficiency of WLAN transmissions. An algorithm called Small Packet Aggregation for Wireless Networks (SPAWN) is also presented in this thesis to improve transmission efficiency of small voice packets in WLANs without introducing further delay to VoIP traffic. The evaluation result shows that after applying the SPAWN algorithm, the VoIP capacity of a single wireless channel can be extended up to 24 simultaneous calls.

This master thesis deals with all types of wireless networks security – in personal, local, metropolitan and also mobile networks. This work is mostly focused on wireless local area networks (WLANs), which are the most widespread at nowadays. This work describes attacks to the wireless local area network, attackers steps and possible protection against it. Some of these attacks are tested in practical part of this work. In this master thesis there were also designed and created two laboratory exercises. One of them is a simulation in the wireless network using Opnet Modeler application. The other exercise is strictly practical type.

Master´s thesis „Security risks of wireless access networks“ deals with wireless access networks, which are the most widespread in this time. The main target is realization of attacks wireless access networks protected by various using methods. This thesis shows main securities gaps, which originate from project this networks. These securities gaps are used for realization attacts in practical part. In the next part I took attention of network´s monitoring possibilities.

Wireless networks are currently the frequent access connection to the local network or the Internet. Until 2005 there was no support in the 802.11 standard priority data and the use of multimedia services in these networks is problematic. Thesis deals with the standard IEEE 802.11 standard and quality of service support including IEEE 802.11e. They discussed methods of access to transmission medium, differences in the MAC sublayer, the reader issues in the transmission of priority data and the requirements for these data. In Opnet Modeler was created wireless network with access points and stations on which they are carried out simulations at different strain of transmitted data. It studied the difference in the use of DCF and EDCF method, used in the network with QoS support. In particular, it examined the behavior of priority voice and video data in both networks. The focus is on key parameters such as throughput, dropping data, packet loss, delay, jitter and the size of broadcasting front. The measured data are analyzed, and differences in the network without the support and promoting the quality of services are compared and evaluated. Part of this work is the role of laboratory in the Opnet Modeler.

Nowadays every wireless radio-communication services encompass huge type of technology used for transfer video, voice or data. Wireless communication is the most expanded branch and many companies are using this technology because of low cost and simply management. The biggest advantage is easy connection to shared wireless medium and allows users of network to move around whole covered area. The most expanded types of wireless networks are called Wireless LAN (WLAN). With rising number of WLANs is rising chance to attack shared wireless medium by hacker and many sensitive information can be stolen or modified. To avoid this chance was created the first security protocol used in WLAN called WEP. Its goal was protect data transmitted trough WLAN as strong as were protected in wired networks. Unfortunately WEP was hiding a big weakness which can be used in a crack of WLAN in a minute with the aid of special software. Example of this kid of software can be Airsnort constructed to monitor shared medium and captured every packet transferred trough this medium. Based on statistical method Airsnort can obtain hidden password in a few minutes. The second type of this software can be Aircrack-ng, which can crack hidden password without any user connected to WLAN. Aircrack-ng uses active techniques to generate network load and can obtain password more effectively and faster. The result of both cases was successful and protection of WLAN was completely cracked. Later was created new security protocol called WPA, which had to fix the cryptography weakness of previous WEP. WPA was only temporary security protocol, during standard 802.11 was developing which had to offer highest security and integrity protection of transferred data trough WLAN. For this reasons was created new version of WPA called WPA2 which satisfy requirements of standard 802.11i. Both protocols WPA/WPA2 contain weakness, which can crash security of WLAN. This crack is based on authentication PSK. Attacker during authentication is using information from four-way handshake between user of WLAN and access point. Based on this information attacker can crack password with the aid of password list attack which took approximately 30 minutes. Based on previous result is important to chose strong password contains alphanumeric string or special strings with satisfy length.