00538nam a2200145 4500008004100000245005800041210005600099100002100155700002200176700001900198700002200217700001800239700001800257856011700275 2006 eng d00aIPv6: The protocol, transition and porting mechanisms0 aIPv6 The protocol transition and porting mechanisms1 aBouras, Christos1 aGkamas, Apostolos1 aStamos, Kostas1 aPrimpas, Dimitris1 aKaraliotas, A1 aGanos, Petros uhttp://telematics.upatras.gr/telematics/publications/ipv6-protocol-transition-and-porting-mechanisms?language=el02111nas a2200157 4500008004100000245010500041210006900146260001200215300001400227520147700241100002101718700002201739700001901761700001801780856015501798 2005 eng d00aArchitecture and Performance Evaluation for Redundant Multicast Transmission Supporting Adaptive QoS0 aArchitecture and Performance Evaluation for Redundant Multicast  cJanuary a 85 - 1103 a

In this paper we describe the architecture of an application that was developed for the transmission of multimedia data, using the multicast mechanism, over the Internet. There are two major issues that have to be considered when designing and implementing such a service, the fairness and the adaptation schemes. The fairness problem results from the fact that Clients with different capabilities have to be served. In our application we use a mechanism that categorizes the Clients into a number of groups according to each Client’s capabilities and (the mechanism) serves each group of Clients with a different multicast stream. With the term “capabilities” we do not only mean the processing power of the Client, but also the capacity and the condition of the network path towards that Client. Because of today’s Internet heterogeneity and the lack of Quality of Service (QoS) support, the Server cannot assume that the Clients will permanently be able to handle a specific bit rate.We have therefore implemented an additional mechanism for the intra-stream bit rate adaptation. The proposed mechanism uses a “friendly” to the network users congestion control policy to control the transmission of the data. We evaluate the adaptive multicast transmission mechanism through a number of experiments and a number of simulations in order to examine its behaviour to a heterogeneous group of Clients and its behaviour against TCP and UDP data streams.

1 aBouras, Christos1 aGkamas, Apostolos1 aStamos, Kostas1 aKaraliotas, A uhttp://telematics.upatras.gr/telematics/publications/architecture-and-performance-evaluation-redundant-multicast-transmission-supporting-0?language=el01427nas a2200169 4500008004100000245007200041210006900113260002000182520081300202100002101015700002201036700001801058700002401076700001901100700001601119856012201135 2005 eng d00aQoS issues in the Research and Academic Networks: The case of GRnet0 aQoS issues in the Research and Academic Networks The case of GRn c23 - 28 October3 a

This paper describes the design and the implementation of QoS services in a high speed backbone network as well as a management tool for the service. The services were designed taking advantage of features provided by the MPLS technology and also by using the DiffServ architecture. The supported QoS services include the IP Premium that tries to provide zero packet loss as well as minimum delay and jitter and the Less Than Best Effort service. In addition we implemented a management tool for the service. The scope of this tool is to allow the users to manage their QoS requests (make a new one, edit, delete or view a request). Also the tool performs admission control and produces the necessary configuration that must be applied on the network in order to implement every service’s request.

1 aBouras, Christos1 aPrimpas, Dimitris1 aKaraliotas, A1 aParaskevas, Mixalis1 aOikonomakos, M1 aSintoris, C uhttp://telematics.upatras.gr/telematics/publications/qos-issues-research-and-academic-networks-case-grnet?language=el01297nas a2200133 4500008004100000245007000041210006600111300001300177520079400190100002100984700001801005700001801023856012201041 2003 eng d00aThe deployment of IPv6 in an IPv4 world and Transition Mechanisms0 adeployment of IPv6 in an IPv4 world and Transition Mechanisms a 86 - 933 aIt is stated that the new version of the IP protocol, IPv6, is the answer to the majority of the problems that were raised during the enormous expansion of the Internet and its transformation to a global communication platform with commercial scope. At the same time it is also stated that IPv6 dominance will not be easy and there will be a period when the two versions of the protocol will co-exist. In this paper we describe some of the main transition mechanisms that can be deployed in order to facilitate the transition process to the new version of the IP protocol. Furthermore, the presented mechanisms are discussed regarding their usability, usefulness and manageability. Describes the way some of these mechanisms were applied to the Greek Research & Technology Network (GRNET).1 aBouras, Christos1 aKaraliotas, A1 aGanos, Petros uhttp://telematics.upatras.gr/telematics/publications/deployment-ipv6-ipv4-world-and-transition-mechanisms?language=el01365nas a2200169 4500008004100000245014200041210006900183260001700252300001500269520064800284100002100932700002200953700001900975700002200994700001801016856016101034 2003 eng d00aIssues for the Performance Monitoring of an Open Source H.323 Implementation Ported to IPv6 – Enabled Networks with QoS Characteristics0 aIssues for the Performance Monitoring of an Open Source H323 Imp c23 - 26 June a 765 - 7713 aOpenH323 is an open source H.323 implementation that has been ported to IPv6. It therefore presents an opportunity to perform experiments and compare the performance of an H.323 application when using the IPv4 stack and when using the IPv6 stack. In this paper we initially introduce briefly the porting procedure and the methodology we used in order to achieve it. We then present the appropriate experiments that have to be performed in order to comparatively evaluate the IPv4 and IPv6 protocol stacks. We also present the results of some initial experiments comparing IPv4 and IPv6 performance and the conclusions that they can lead us to.1 aBouras, Christos1 aGkamas, Apostolos1 aStamos, Kostas1 aPrimpas, Dimitris1 aKaraliotas, A uhttp://telematics.upatras.gr/telematics/publications/issues-performance-monitoring-open-source-h323-implementation-ported-ipv6-%E2%80%93-enabled?language=el02040nas a2200169 4500008004100000245002800041210002800069260001000097520155000107100002101657700001801678700002401696700001701720700002101737700001901758856009301777 2003 eng d00aWireless School Network0 aWireless School Network cApril3 aThe architecture of the wireless network consists of 3 main parts. The wireless infrastructure, the connection of the wireless island to the rest network and the interconnection between the neighboring schools a near one participating in the wireless network. The wireless connection supports Point-to-Multipoint technology [3] and uses the frequency band 2,4 Ghz to 2,4835 Ghz. The reserved bandwidth of this wireless LAN is order of magnitude 11 Mbps. In each school the bridge device is connected to a newly equipped Fast Ethernet switch interconnecting the internal schools network to the wireless network. Between the schools a fast Ethernet network is built using copper and Fiber optic cabling. The interconnection of the wireless network upstream to the backbone is achieved with the use of the link between the E.A.O and the local main distribution node of the EDUNET network. This link had to be upgrade because it will carry the traffic from the wireless network too. The selected solution was the VDSL technology by engaging the appropriate modems over a two-wire leased line between the E.A.O and the main node. We have a selected point in each school unit that wireless bridge and antenna will be installed. The wireless bridge must stand near to antenna because long cabling distances will produce noise in the transmission signal. The wireless bridge will be housed at waterproof cabinet, which offers all the necessary specifications for protection and electric feeding. The waterproof cabinet is installed at the antenna pylon.1 aBouras, Christos1 aKaraliotas, A1 aParaskevas, Mixalis1 aPapoutsis, V1 aNtokos, Christos1 aDrosopoulos, N uhttp://telematics.upatras.gr/telematics/publications/wireless-school-network?language=el01585nas a2200157 4500008004100000245010600041210006900147260001900216300001500235520094300250100002101193700002201214700001901236700001801255856015401273 2002 eng d00aBehaviour Investigation using Simulation for Redundant Multicast Transmission Supporting Adaptive QoS0 aBehaviour Investigation using Simulation for Redundant Multicast c27 - 30 August a 112 - 1173 aIn this paper we describe a mechanism for redundant multicast transmission of multimedia data supporting adaptive QoS over the Internet and we investigate its behaviour using simulation. There are two major issues that have to be considered when designing and implementing such a mechanism, the fairness, which is the ability to cope with receiver heterogeneity, and the adaptation schemes. The proposed mechanism uses a friendly to the network users congestion control policy to control the transmission of the data. We evaluate the adaptive multicast transmission mechanism through a number of simulations in order to examine its behaviour to a heterogeneous group of receivers and its behaviour against TCP and UDP data streams. Main conclusion of the simulation was that the proposed mechanism has friendly behaviour against the dominant traffic types of today’s Internet and treats a heterogeneous group of receivers with fairness.1 aBouras, Christos1 aGkamas, Apostolos1 aStamos, Kostas1 aKaraliotas, A uhttp://telematics.upatras.gr/telematics/publications/behaviour-investigation-using-simulation-redundant-multicast-transmission-supporting?language=el00965nas a2200145 4500008004100000245006300041210006200104260001700166300001300183520045400196100002100650700001800671700001800689856011200707 2002 eng d00aTransition Strategies from IPv4 to IPv6: The case of GRNET0 aTransition Strategies from IPv4 to IPv6 The case of GRNET c16 - 18 July a 89 - 963 aIn this paper we describe the results that came out from the project of employing the IPv6 protocol over the Greek Research & Technology Network (GRNET). In the way of this process one of the big issues that had to be considered was the transition strategy that would be deployed. The main goals of a transition strategy are to be smooth enough and therefore to put the less of configuration overhead to the end users and the network administrators.1 aBouras, Christos1 aKaraliotas, A1 aGanos, Petros uhttp://telematics.upatras.gr/telematics/publications/transition-strategies-ipv4-ipv6-case-grnet?language=el01624nas a2200157 4500008004100000245010500041210006900146260001900215300001500234520098400249100002101233700002201254700001901276700001801295856015301313 2001 eng d00aArchitecture and Performance Evaluation for Redundant Multicast Transmission Supporting Adaptive QoS0 aArchitecture and Performance Evaluation for Redundant Multicast  c9 - 12 October a 585 - 5923 a

In this paper we describe the architecture of an application that was developed for the transmission of multimedia data, using the multicast mechanism, over the Internet. There are two major issues that have to be considered when designing and implementing such a service, the fairness and the adaptation schemes. In our application we use a mechanism that categorizes the receivers into a number of groups according to each receiver’s capabilities and (the mechanism) serves each group of users with a different multicast stream. We have also implemented an additional mechanism for the intra-stream bit rate adaptation. The proposed mechanism uses a “friendly” to the network users congestion control policy to control the transmission of the data. We evaluate the adaptive multicast transmission mechanism through a number of experiments in order to examine its behaviour to a heterogeneous group of receivers and its behaviour against TCP and UDP data streams.

1 aBouras, Christos1 aGkamas, Apostolos1 aStamos, Kostas1 aKaraliotas, A uhttp://telematics.upatras.gr/telematics/publications/architecture-and-performance-evaluation-redundant-multicast-transmission-supporting?language=el01727nas a2200157 4500008004100000245008100041210006900122260001900191300001500210520112500225100002101350700002201371700001901393700001801412856013901430 2001 eng d00aAn Architecture for Redundant Multicast Transmission Supporting Adaptive QoS0 aArchitecture for Redundant Multicast Transmission Supporting Ada c7 - 9 November a 133 - 1423 aIn this paper we describe the architecture and the implementation of an application that was developed for the transmission of multimedia data, using the multicast mechanism, over the Internet. There are two major issues that have to be considered when designing and implementing such a service, the fairness and the adaptation schemes. The fairness problem results from the fact that receivers with different capabilities have to be served. In our application we use a mechanism that categorizes the receivers into a number of groups according to each receiver’s capabilities and (the mechanism) serves each group of users with a different multicast stream. With the term “capabilities” we do not only mean the processing power of the client, but also the capacity and the condition of the network path towards that client. Because of today’s Internet heterogeneity and the lack of Quality of Service (QoS) support, the sender cannot assume that the receivers will permanently be able to handle a specific bit rate. We have therefore implemented an additional mechanism for the intra-stream bit rate adaptation.1 aBouras, Christos1 aGkamas, Apostolos1 aStamos, Kostas1 aKaraliotas, A uhttp://telematics.upatras.gr/telematics/publications/architecture-redundant-multicast-transmission-supporting-adaptive-qos?language=el