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Wireless networks introduce a whole range of challenges to the traditional TCP/IP network, especially Virtual Private Network (VPN). Changing IP address is a difficult issue for VPNs in wireless networks because IP addresses are used as one of the identifiers of a VPN connection and the change of IP addresses will break the original connection. The current solution to this problem is to run VPN tunnels over Mobile IP (MIP). However, Mobile IP itself has significant problems in performance and security and that solution is inefficient due to double tunneling. This thesis proposes and implements a new and novel solution on simulators and real devices to solve the mobility problem in a VPN. The new solution adds mobility support to existing L2TP/IPsec (Layer 2 Tunneling Protocol/IP Security) tunnels. The new solution tunnels Layer 2 packets between VPN clients and a VPN server without using Mobile IP, without incurring tunnel-re-establishment at handoff, without losing packets during handoff, achieves better security than current mobility solutions for VPN, and supports fast handoff in IPv4 networks. Experimental results on a VMware simulation showed the handoff time for the VPN tunnel to be 0.08 seconds, much better than the current method which requires a new tunnel establishment at a cost of 1.56 seconds. Experimental results with a real network of computers showed the handoff time for the VPN tunnel to be 4.8 seconds. This delay was mainly caused by getting an IP address from DHCP servers via wireless access points (4.6 seconds). The time for VPN negotiation was only 0.2 seconds. The experimental result proves that the proposed mobility solution greatly reduces the VPN negotiation time but getting an IP address from DHCP servers is a large delay which obstructs the real world application. This problem can be solved by introducing fast DHCP or supplying an IP address from a new wireless access point with a strong signal while the current Internet connection is weak. Currently, there is little work on fast DHCP and this may open a range of new research opportunities.

Thesis (M.Sc.) - Carleton University, 2002. / Includes bibliographical references (p. 107-110). Also available in electronic format on the Internet.

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Dagens företag vill ge anställda möjlighet att jobba hemifrån eller på resande fot. En vanlig lösning för att möjliggöra detta är virtual private network (VPN). VPN ger en användare tillgång till interna resurser på företaget från ett externt nät, exempelvis via Internet. Detta gör att användare kan komma åt de interna resurserna på ett säkert sätt. Vilken VPN-teknik är då att föredra för att få en så snabb, säker och pålitlig anslutning som möjligt? Detta examensarbete tar upp olika VPN-tekniker. Vi beskriver vanliga VPN-protokoll som L2TP, IPSec och PPTP. Hur användare autentiseras på ett säkert och smidigt sätt samt metoder att göra sin VPN-anslutning säker. Vi redovisar också den lösning vi har implementerat hos Confidence, för vilka arbetet utfördes. Problemen med att använda de produkter som redan fanns på företaget beskrivs. Förslag på lösningar ges för att lösa dessa problem i framtida arbeten. / Companies of today want to give their employees the opportunity to work from home or while they travel. A common solution to accomplish this is to implement a VPN over top of the existing network. Using VPN gives the employees access to the company’s local area network from outside, via the internet. The VPN provides a secure channel for these employees to connect to the local services attached to the company’s network that they need to reach. Which VPN technology is most suitable to deliver a secure, fast, and reliable connection to theses employees? In this thesis examines we are taking a closer look at different VPN solutions. We describe different VPN-protocols like L2TP, IPSec and PPTP. How to authenticate users in a secure and flexible way and also methods used to make the VPN-connection secure. Lastly we will show the solution we have implemented at the company Confidence, for whom we made the solution. The difficulties in using existing products with the company’s infrastructure are described. Suggestions are offered for future work to address these problems.

<p> </p><p>Syftet med denna undersökning är att ta reda på vilken mjukvarubaserad fjärranslutningslösning som passar för ett mindre företag, då de har mindre ekonomiska tillgångar än ett större företag behöver de vara mer noggranna med sina produktval. Arbetet är utfört med litteraturstudier och en enkätundersökning till ett tiotal mindre företag, samt en laborationsmiljö där tester av de olika fjärranslutningslösningarnas egenskaper har utförts.</p><p>Område valdes då ämnet fjärranslutning knappt behandlads under utbildningstiden, och fördjupar sig därför inom området.</p><p>Resultatet visar vad mindre företag anser vara de viktigaste egenskaperna med en fjärranslutningslösning. Även de värden som uppkom vid tester i laborationsmiljön kommer att presenteras i resultatet. De samlade resultaten kommer sedan visa på vilken mjukvarubaserad lösning som passar bäst för ett mindre företag.</p><p> </p> / <p><p>The purpose of this survey is to figure out which software based remote access solution that fits a smaller company, hence they have less economy assets than a larger company they need to be more thorough with their products of choice. The work is performed with literature studies and a survey of a dozen smaller companies, and also a laboratory environment where properties of the different remote access solutions are performed.</p><p>This area was chosen because the subject of remote access scarcely was treated during our education, and become engrossed in this area.</p><p>The result shows what the companies consider to be the most important properties with a remote access and also the products results from the tests. Also the values that occurred during testing in a laboratory environment will be presented in the results. The combined results will then show which software-based solution that is best suited for a small company.</p></p>

Syftet med denna undersökning är att ta reda på vilken mjukvarubaserad fjärranslutningslösning som passar för ett mindre företag, då de har mindre ekonomiska tillgångar än ett större företag behöver de vara mer noggranna med sina produktval. Arbetet är utfört med litteraturstudier och en enkätundersökning till ett tiotal mindre företag, samt en laborationsmiljö där tester av de olika fjärranslutningslösningarnas egenskaper har utförts. Område valdes då ämnet fjärranslutning knappt behandlads under utbildningstiden, och fördjupar sig därför inom området. Resultatet visar vad mindre företag anser vara de viktigaste egenskaperna med en fjärranslutningslösning. Även de värden som uppkom vid tester i laborationsmiljön kommer att presenteras i resultatet. De samlade resultaten kommer sedan visa på vilken mjukvarubaserad lösning som passar bäst för ett mindre företag. / The purpose of this survey is to figure out which software based remote access solution that fits a smaller company, hence they have less economy assets than a larger company they need to be more thorough with their products of choice. The work is performed with literature studies and a survey of a dozen smaller companies, and also a laboratory environment where properties of the different remote access solutions are performed. This area was chosen because the subject of remote access scarcely was treated during our education, and become engrossed in this area. The result shows what the companies consider to be the most important properties with a remote access and also the products results from the tests. Also the values that occurred during testing in a laboratory environment will be presented in the results. The combined results will then show which software-based solution that is best suited for a small company.

With the increase in bandwidth, more widespread distribution of media, and increased capability of mobile devices, multimedia streaming has not only become feasible, but more economical in terms of space occupied by the media file and the costs involved in attaining it. Although much attention has been paid to peer to peer media streaming over the Internet using HTTP and RTSP, little research has focussed on the use of the Bluetooth protocol for streaming audio and video between mobile devices. This project investigates the feasibility of Bluetooth as a protocol for audio and video streaming between mobile phones using the J2ME platform, through the analysis of Bluetooth protocols, media formats, optimum packet sizes, and the effects of distance on transfer speed. A comparison was made between RFCOMM and L2CAP to determine which protocol could support the fastest transfer speed between two mobile devices. The L2CAP protocol proved to be the most suitable, providing average transfer rates of 136.17 KBps. Using this protocol a second experiment was undertaken to determine the most suitable media format for streaming in terms of: file size, bandwidth usage, quality, and ease of implementation. Out of the eight media formats investigated, the MP3 format provided the smallest file size, smallest bandwidth usage, best quality and highest ease of implementation. Another experiment was conducted to determine the optimum packet size for transfer between devices. A tradeoff was found between packet size and the quality of the sound file, with highest transfer rates being recorded with the MTU size of 668 bytes (136.58 KBps). The class of Bluetooth transmitter typically used in mobile devices (class 2) is considered a weak signal and is adversely affected by distance. As such, the final investigation that was undertaken was aimed at determining the effects of distance on audio streaming and playback. As can be expected, when devices were situated close to each other, the transfer speeds obtained were higher than when devices were far apart. Readings were taken at varying distances (1-15 metres), with erratic transfer speeds observed from 7 metres onwards. This research showed that audio streaming on the J2ME platform is feasible, however using the currently available class of Bluetooth transmitter, video streaming is not feasible. Video files were only playable once the entire media file had been transferred.