A 2D Markov-Chain analysis is used to model channel occupancy within a high mobility picocell based network including handover and outage events. Single-cell performance is evaluated by the Grade of Service and by the call dropping probability. The relations between different picocellular network parameters are analyzed and guidelines for proper MAC protocol design are given.

The VoIP suite of protocols are extended to propose a computer network capable of terrestrially storing in real time the flight data records and cockpit voice records of every commercial flight. The design process took into account the satellite access, the aviation, the black box manufacturing and the VoIP industriespsila recent developments. As a result, a system architecture development framework and a transport-signaling protocol are proposed. The economic feasibility of the proposal is finally addressed.

While transparent WDM optical networks become more and more popular as the basis of the Next Generation Internet (NGI) infrastructure, such networks raise many unique security issues. The existing protection schemes which only consider unintended failures and only rely on postmortem detection and reaction are not sufficient to provide security assurance for such infrastructures which require timely protection from malicious sabotage as well as inadvertent faults. Moreover, as may have been observed from past practices, providing a particular solution specialized to each incessantly discovered new problems would not dramatically improve the situation. In order to increase the security of future networks we will need to imbed intelligence into the network such that they can continuously learn from the experience in faults and self-organize to protect themselves from potential failures caused by malicious new attacks or ordinary reliability problems. In this paper, we present results with simple vulnerability and attack scenarios in order to demonstrate how the self-organization helps to adapts against new vulnerabilities and avoid attacks.

A detailed analytical traffic model for all-optical wavelength division multiplexing (WDM) photonic packet switched networks is presented and the requirements for buffer size, and link dimensions are analyzed. This paper shows that due to the topology, packets may generate traffic bottlenecks produced by a tendency of the routing scheme to send packets with different destinations through preferred paths. This effect increases the traffic load and hence the probability of blocking at the output links of specific routers in the network and therefore a large buffer depth is required or an increment in the number of fibers per link. Two router architectures are analyzed and it is shown that WDM all-optical router architectures with shared contention resolution resources are the best candidates to reduce hardware volume and cost of all-optical networks.

We discuss the introduction/implementation of optical IP routers, then we introduce a novel scheduling algorithm incorporating void filling and aimed at optical routing of asynchronous, variable packet length packets. We describe its structure and discuss the complexity issues. Albeit introduced with the purpose of cancelling expensive optical synchronization, we argue that this approach represents the most viable all-optical approach for implementing packets-over-SONET (IP-centric scenario). We also present simulations under self-similar traffic conditions which point to the inefficiency of optical buffering to combat the effects of self-similarity, and we outline alternative strategies for proper buffer dimensioning.

Wavelength conversion has been shown to reduce the probability of blocking in both circuit-switching and packet-switching wavelength routed optical networks (WRONs). The effectiveness of the blocking reduction depends on the topology, and is known to be best for meshed topologies, where the average number of hops per path is large. This paper shows that by exploiting wavelength conversion, routing without buffers, known as hot-potato, becomes an interesting option for packet switching WRONs with meshed topologies, such as Manhattan Street (MS) Network and ShuffleNet (SN). The results show that, by using more than 4 wavelengths, a 64 node MS or SN network can work at full load with a hop delay within one hop from its lowest achievable value. We also show that using delay-line routing buffers at the node is a much more effective way of reducing blocking than using wavelength conversion.

The teletraffic/transmission performance of regular two-connected multi-hop cell-switching optical networks in uniform traffic under hybrid store-and-forward is presented. The Manhattan street (MS) network and Shufflenet (SN) are compared in terms of average queueing delay, queue size, transit delay, throughput, and bit error rate (BER) for intensity modulation/direct-detection (IM/DD) both analytically and by simulation. A hybrid semi-transparent store-and-forward node architecture is presented. Cells are electronically stored just in the case of conflict to avoid deflection, otherwise the cells will traverse the node without opto-electronic conversion. This architecture performs well, in terms of throughput, propagation delay and BER. It is also shown that by combining deflection routing with the store-and-forward scheme the network can accommodate two different bit-rates. This suggests that the proposed hybrid scheme may have good potential for future multimedia networks.

The transmission performance of regular two-connected multi-hop transparent optical networks in uniform traffic under hot-potato, single-buffer deflection routing schemes is presented. The Manhattan Street (MS) network and ShuffleNet (SN) are compared in terms of bit error rate (BER) and packet error rate (PER) both analytically and by simulation. We implement a novel strategy of analysis, in which the transmission performance evaluation is linked to the traffic randomness of the networks. Amplifier spontaneous emission (ASE) noise, and device-induced crosstalk severely limit the characteristics of the network, such as propagation distance, sustainable traffic, and bit-rate. Our results indicate that under the same load the BER performance of single-buffer deflection routing is worse than hot-potato. However, at BER=10/sup -9/ single-buffer has a higher throughput than hot-potato. It is shown that the feasibility of deflection routing in transparent networks with MS and SN topologies heavily depends on the power coupling coefficient of the routing space switch used in each node.