@book {3154, title = {IPv6: The protocol, transition and porting mechanisms}, series = {Ellinika Grammata}, year = {2006}, author = {Christos Bouras and Apostolos Gkamas and Kostas Stamos and Dimitris Primpas and A Karaliotas and Petros Ganos} } @article {3027, title = {Architecture and Performance Evaluation for Redundant Multicast Transmission Supporting Adaptive QoS}, journal = {Tools and Applications, Kluwer Academic Publishers, Vol. 25, No. 1}, year = {2005}, month = {January}, pages = { 85 - 110}, abstract = {

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{\textquoteright}s capabilities and (the mechanism) serves each group of Clients with a different multicast stream. With the term {\textquotedblleft}capabilities{\textquotedblright} 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{\textquoteright}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 {\textquotedblleft}friendly{\textquotedblright} 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.

}, author = {Christos Bouras and Apostolos Gkamas and Kostas Stamos and A Karaliotas} } @conference {2695, title = {QoS issues in the Research and Academic Networks: The case of GRnet}, booktitle = {Industrial Conference on Multi-Provider QoS/SLA Internetworking (MPQSI 2005), Tahiti, French Polynesia}, year = {2005}, month = {23 - 28 October}, abstract = {

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{\textquoteright}s request.

}, author = {Christos Bouras and Dimitris Primpas and A Karaliotas and Mixalis Paraskevas and M Oikonomakos and C Sintoris} } @article {3047, title = {The deployment of IPv6 in an IPv4 world and Transition Mechanisms}, journal = {Internet Research: Electronic Networking, Applications and Policy, Emerald, Volume 13, Number 2}, year = {2003}, pages = { 86 - 93}, abstract = {It 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).}, author = {Christos Bouras and A Karaliotas and Petros Ganos} } @conference {2752, title = {Issues for the Performance Monitoring of an Open Source H.323 Implementation Ported to IPv6 {\textendash} Enabled Networks with QoS Characteristics}, booktitle = {The 2003 International Conference in Internet Computing (IC 2003), Las Vegas, Nevada, USA}, year = {2003}, month = {23 - 26 June}, pages = { 765 - 771}, abstract = {OpenH323 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.}, author = {Christos Bouras and Apostolos Gkamas and Kostas Stamos and Dimitris Primpas and A Karaliotas} } @article {3049, title = {Wireless School Network}, journal = {Learning Technology Newsletter {\textendash} IEEE Learning Technology Task Force(on line), Vol. 5, Issue 2}, year = {2003}, month = {April}, abstract = {The 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.}, author = {Christos Bouras and A Karaliotas and Mixalis Paraskevas and V Papoutsis and Christos Ntokos and N Drosopoulos} } @conference {2767, title = {Behaviour Investigation using Simulation for Redundant Multicast Transmission Supporting Adaptive QoS}, booktitle = {10th IEEE International Conference on Networks (ICON 2002), Singapore}, year = {2002}, month = {27 - 30 August}, pages = { 112 - 117}, abstract = {In 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{\textquoteright}s Internet and treats a heterogeneous group of receivers with fairness.}, author = {Christos Bouras and Apostolos Gkamas and Kostas Stamos and A Karaliotas} } @conference {2776, title = {Transition Strategies from IPv4 to IPv6: The case of GRNET}, booktitle = {3rd International Network Conference-INC 2002, Plymouth, UK}, year = {2002}, month = {16 - 18 July}, pages = { 89 - 96}, abstract = {In 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.}, author = {Christos Bouras and A Karaliotas and Petros Ganos} } @conference {2789, title = {Architecture and Performance Evaluation for Redundant Multicast Transmission Supporting Adaptive QoS}, booktitle = {9th International Conference on Software, Telecommunications and Computer Networks (SoftCom 2001) Split, Dubrovnik(Croatia), Ancona, Bari (Italy), vol II}, year = {2001}, month = {9 - 12 October}, pages = { 585 - 592}, abstract = {

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{\textquoteright}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 {\textquotedblleft}friendly{\textquotedblright} 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.

}, author = {Christos Bouras and Apostolos Gkamas and Kostas Stamos and A Karaliotas} } @conference {2788, title = {An Architecture for Redundant Multicast Transmission Supporting Adaptive QoS}, booktitle = {7th International WORKSHOP ON MULTIMEDIA SYSTEMS, Capri, Italy}, year = {2001}, month = {7 - 9 November}, pages = { 133 - 142}, abstract = {In 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{\textquoteright}s capabilities and (the mechanism) serves each group of users with a different multicast stream. With the term {\textquotedblleft}capabilities{\textquotedblright} 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{\textquoteright}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.}, author = {Christos Bouras and Apostolos Gkamas and Kostas Stamos and A Karaliotas} }