The efficient use of resources and the lossless transfer of data bursts in future optical network... more The efficient use of resources and the lossless transfer of data bursts in future optical networks requires the accurate knowledge of the available bandwidth for each network link. Such information is important in monitoring congestions and can be used by appropriate load balancing and congestion avoidance mechanisms. In this paper we propose a mechanism for monitoring and subsequently managing bandwidth resources, using the Simple Network Management Protocol (SNMP). In the proposed mechanism, link bandwidth availability is not a scalar parameter, but a function of time that records the future utilization of the link. For every output port, each agent-node maintains a simple data structure in the form of a table that records the utilization profile of that outgoing link. With the addition of new objects in the Management Information Base (MIB) of each agent-node and proper synchronization, SNMP can be used to update and retrieve the reservations made on the links in order to obtain an instant picture of the network traffic situation.
All-optical clock recovery is demonstrated from pseudo-data patterns at 30 Gb/s. The circuit is b... more All-optical clock recovery is demonstrated from pseudo-data patterns at 30 Gb/s. The circuit is based on the optical gain modulation of a semiconductor optical amplifier fiber laser. The recovered clock is a 2.7-ps pulse train, with very low modulation pattern even in the presence of more than 200 consecutive 0's in the data signal.
Recent advances in the all-optical signal processing domain report high-speed and nontrivial func... more Recent advances in the all-optical signal processing domain report high-speed and nontrivial functionality directly implemented in the optical layer. These developments mean that the all- optical processing of packet headers has a future. In this article we address various important control plane issues that must be resolved when designing networks based on all-optical packet-switched nodes.
The purpose of this paper is to assess the impact of timer-based burst assembly algorithms for TC... more The purpose of this paper is to assess the impact of timer-based burst assembly algorithms for TCP traffic. We present an analysis for short, medium and long assembly times and investigate segment and flow distribution over the assembled bursts. Further, we also analyze their impact on the congestion window evolution and on the effective throughput achieved. It has been found out that short assembly times are ideally suitable for sources with small congestion windows, allowing for a speed up, while large assembly times yield a lower throughput variation among the individual assembled flows. For long assembly times, the transfer of more segments from the same source is trading off the increase of the burstification delay but no throughput gain is obtained. However, large assembly times smooth out individual flow performance and provide a significant lower variation of throughput. To this end, in this paper, we propose a new adaptive burst assembly algorithm that dynamically assigns flows to different burstifiers based on their instant window size.
In future transparent optical networks, it is important to consider the impact of physical impair... more In future transparent optical networks, it is important to consider the impact of physical impairments in the routing and wavelengths assignment process, to achieve efficient connection provisioning. In this paper, we use classical multi-objective optimization (MOO) strategies and particularly genetic algorithms to jointly solve the impairment aware RWA (IA-RWA) problem. Fiber impairments are indirectly considered through the insertion of the path length and the number of common hops in the optimization process. It is shown that blocking is greatly improved, while the obtained solutions truly converge towards the Pareto front that constitutes the set of global optimum solutions. We have evaluated our findings, using an Q estimator tool, that calculates the signal quality of each path analytically.
The efficient use of resources and the lossless transfer of data bursts in future optical network... more The efficient use of resources and the lossless transfer of data bursts in future optical networks requires the accurate knowledge of the available bandwidth for each network link. Such information is important in monitoring congestions and can be used by appropriate load balancing and congestion avoidance mechanisms. In this paper we propose a mechanism for monitoring and subsequently managing bandwidth resources, using the Simple Network Management Protocol (SNMP). In the proposed mechanism, link bandwidth availability is not a scalar parameter, but a function of time that records the future utilization of the link. For every output port, each agent-node maintains a simple data structure in the form of a table that records the utilization profile of that outgoing link. With the addition of new objects in the Management Information Base (MIB) of each agent-node and proper synchronization, SNMP can be used to update and retrieve the reservations made on the links in order to obtain an instant picture of the network traffic situation.
All-optical clock recovery is demonstrated from pseudo-data patterns at 30 Gb/s. The circuit is b... more All-optical clock recovery is demonstrated from pseudo-data patterns at 30 Gb/s. The circuit is based on the optical gain modulation of a semiconductor optical amplifier fiber laser. The recovered clock is a 2.7-ps pulse train, with very low modulation pattern even in the presence of more than 200 consecutive 0's in the data signal.
Recent advances in the all-optical signal processing domain report high-speed and nontrivial func... more Recent advances in the all-optical signal processing domain report high-speed and nontrivial functionality directly implemented in the optical layer. These developments mean that the all- optical processing of packet headers has a future. In this article we address various important control plane issues that must be resolved when designing networks based on all-optical packet-switched nodes.
The purpose of this paper is to assess the impact of timer-based burst assembly algorithms for TC... more The purpose of this paper is to assess the impact of timer-based burst assembly algorithms for TCP traffic. We present an analysis for short, medium and long assembly times and investigate segment and flow distribution over the assembled bursts. Further, we also analyze their impact on the congestion window evolution and on the effective throughput achieved. It has been found out that short assembly times are ideally suitable for sources with small congestion windows, allowing for a speed up, while large assembly times yield a lower throughput variation among the individual assembled flows. For long assembly times, the transfer of more segments from the same source is trading off the increase of the burstification delay but no throughput gain is obtained. However, large assembly times smooth out individual flow performance and provide a significant lower variation of throughput. To this end, in this paper, we propose a new adaptive burst assembly algorithm that dynamically assigns flows to different burstifiers based on their instant window size.
In future transparent optical networks, it is important to consider the impact of physical impair... more In future transparent optical networks, it is important to consider the impact of physical impairments in the routing and wavelengths assignment process, to achieve efficient connection provisioning. In this paper, we use classical multi-objective optimization (MOO) strategies and particularly genetic algorithms to jointly solve the impairment aware RWA (IA-RWA) problem. Fiber impairments are indirectly considered through the insertion of the path length and the number of common hops in the optimization process. It is shown that blocking is greatly improved, while the obtained solutions truly converge towards the Pareto front that constitutes the set of global optimum solutions. We have evaluated our findings, using an Q estimator tool, that calculates the signal quality of each path analytically.
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Papers by Kyriakos Vlachos