Search results for "ComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKS"
showing 10 items of 449 documents
QoS Mechanisms for IEEE 802.11 Wireless LANs
2004
Currently the Internet provides users with access to information across the world using IP technology. Until now most access points to the Internet have been fixed stations at given locations, but with increasing sales of mobile devices, mobility has become a major trend. Therefore, the Internet is becoming more and more heterogeneous due to the recent explosion of wireless networks. The IEEE 802.11 wireless LAN (WLAN) is the most widely used WLAN standard nowadays. Currently the IEEE 802.11 standard specifies an over-the-air interface between wireless devices. However, QoS services over this technology are still being defined aiming to provide support to multiple applications. Thus, a larg…
Statistical learning and multiple linear regression model for network selection using MIH
2014
Award of Appreciation; International audience; A key requirement to provide seamless mobility and guaranteeing Quality of Service in heterogeneous environment is to select the best destination network during handover. In this paper, we propose a new schema for network selection based on Multiple Linear Regression Model (MLRM). A horough investigation, on a huge live data collected from GPRS/UMTS networks led to identify the Key Performance Indicators (KPIs) that play the most important role in the handover process. These KPIs are: Received Signal Code Power (RSCP), received energy per chip (Ec/No) and Available Bandwidth (ABW) of the destination network. To extract a handover model from col…
Evaluation of IP over Bluetooth
2002
Masteroppgave i informasjons- og kommunikasjonsteknologi 2002 - Høgskolen i Agder, Grimstad The increasing use of Wireless technologies suggest that this kind of technology has a bright future. Today the most popular Wireless Local Area Networks are WLAN 802.11 and Bluetooth. They both have their strengths in different environments. Bluetooth was not initially an Internet technology, but over the years the focus on implementing Bluetooth nodes with Internet capability has increased. When we want to run IP over Bluetooth we need some kind of gateway to the Internet from Bluetooth, a network access point. This will be an important device in the thesis. The Bluetooth Special Interest Group has…
Internet Telephony in Ubiquitous Computing Environments
2007
Nowadays VoIP plays an important role in communication, and more and more people use VoIP instead of traditional telephones because of low cost, accessibility and improved quality. However, one of disadvantages of VoIP is that users have to receive the Internet calls by headset and microphone, which are attached to a PC. This way restricts the users’ mobility and doesn’t meet the need of modern users. An innovative improvement would be to use some existing wireless technology to impart mobility to VoIP calls. We propose to use Bluetooth due to its widespread availability in already ubiquitous mobile phone market. Bluetooth is a short-range communication protocol intended to replace the cabl…
SCADA Intrusion Detection System Test Framework
2017
Master's thesis Information- and communication technology IKT590 - University of Agder 2017 Supervisory control and data acquisition (SCADA) systems play an important role in our critical infrastructure (CI). Several of the protocols used in SCADA communication are old and lack of security mechanisms. This master thesis presents a SCADA Intrusion Detection System Test Framework that can be used to simulate SCADA traffic and detect malicious network activity. The framework uses a signature-based approach and utilize two different IDS engines, Suricata and Snort. The IDS engines include rule-sets for the IEC 60870-5-104, DNP3 and Modbus protocols. The IDS engines ships detected events to a di…
IPv6 : prospects and problems : a technical and management investigation into the deployment of IPv6
2003
Masteroppgave i informasjons- og kommunikasjonsteknologi 2003 - Høgskolen i Agder, Grimstad IPv4 has been used for over twenty years, and will most likely be used in many years ahead. However, we are now experiencing that the IPv4 address space is running out, resulting in restrictions on who will be able to get these types of addresses assigned to them. Methods such as Network Address Translator (NAT) have been developed and implemented in order to save the IPv4 address space. It is said that this is not a good enough solution, as such techniques introduce new problems at the same time solving some. A new version of the Internet Protocol, IPv6, has been developed and is likely to replace I…
Study and performance evaluation of transport layer protocols over heterogeneous radio and satellite networks
2006
Masteroppgave i informasjons- og kommunikasjonsteknologi 2006 - Høgskolen i Agder, Grimstad Satellites have for some years made it possible to transfer data over long distances, and from desolated locations. Due to their natural broadcast ability they have some major advantages compared to terrestrial links. This ability has made satellites a useful tool for military, science, multimedia and wireless communication. Compared to a few years ago, we are today able to make more accurate measurements, in different environments. Sensors have recent years become more intelligent, and can work independently without being controlled by humans or computers. Other improvements are their mobility, and …
Mechanisms for OAM on MPLS in large IP backbone networks
2002
Masteroppgave i informasjons- og kommunikasjonsteknologi 2002 - Høgskolen i Agder, Grimstad The telecom industry has an ongoing work on the Operation and Maintenance (OAM) mechanisms for the MultiProtocol Label Switching (MPLS) technology. We are expecting that this technology will be the future platform for sending Internet Protocol (IP) packets through the backbone networks. OAM functionalities that exist or are proposed for MPLS are: Reachability and failure detection, avoidance of congested routers, Simple Network Management Protocol (SNMP) features, fast rerouting functions, traffic engineering and ad-hoc mechanisms like Ping. Our work shows that through a comparison of OAM mechanisms …
SIP based IP-telephony network security analysis
2004
Masteroppgave i informasjons- og kommunikasjonsteknologi 2004 - Høgskolen i Agder, Grimstad This thesis evaluates the SIP Protocol implementation used in the Voice over IP (VoIP) solution at the fibre/DSL network of Èlla Kommunikasjon AS. The evaluation focuses on security in the telephony service, and is performed from the perspective of an attacker trying to find weaknesses in the network. For each type of attempt by the malicious attacker, we examined the security level and possible solutions to flaws in the system. The conclusion of this analysis is that the VoIP service is exploitable, and that serious improvements are needed to achieve a satisfying level of security for the system.
Security in GPRS
2001
Masteroppgave i informasjons- og kommunikasjonsteknologi 2001 - Høgskolen i Agder, Grimstad GPRS offers the user an “always on” connection to Internet and Intranet. Some of the services may require high level of security. This can be financial transaction over the Internet, or exchange of confidential documents from a company’s Intranet to an employee. It is important to have strong focus on the security, so companies and persons that demand high level of security can take advantage of the services GPRS offered. What normally happens is that the services wins against the security. This is in most cases adequate security for what a normal subscriber requires. This thesis covers which securit…