In the sea surface salinity (SSS) application, the data collected by the buoys need to be uploaded as the satellite passes through. Fast sensor identification is a novel technique that can be employed to underpin fair and efficient media access in the SSS application. It deviates from the existing conventional media access control schemes including the random access algorithms and out-of-band signaling methods. These approaches do not take advantage of the possible prediction of the buoy locations. Hence, the valuable time is wasted on resolving collisions. In this paper, we propose a fast sensor identification algorithm that allows the satellite to quickly discover the buoys in its footprint. The upload bandwidth can be granted to the buoys once they are identified. We assume a ground data or control center can provide buoy distribution to the satellite. Armed with this information, the proposed algorithm constantly builds optimal query trees for buoy discovery. The tree is constructed so that it will be fast to confirm the buoys which are expected to be in the area. The tree will also be flexible to accommodate prediction errors. That is, it will find all buoys in the satellite's coverage area. By computer simulations, we compare the proposed algorithm against other automatic identifying techniques such as the binary tree algorithm (BTA) and the query tree algorithm (QTA). It is shown that our approach can reduce the number of reading requirement by the satellite for sensor identification.

Packet marking is a popular technique used in IP traceback. The existing packet marking techniques are categorized into probabilistic packet marking (PPM) and deterministic packet marking (DPM). Each has their respective strengths and weaknesses. In this paper, we propose a novel protocol, called cyclical deterministic packet marking (CDPM), to address the issues challenging the existing approaches. CDPM demands routers along the attack path to deterministically mark the packets in a sequential and cyclical fashion. This new method exhibits some unique advantages. When compared with probabilistic marking techniques, our approach requires much less marked packets to reconstruct the attack path. It is also more resilient to packet spoofing and, in particular, packet loss. Furthermore, the marking and decoding computation is of reasonable complexity. It can also reveal more complete path than the existing DPM based mechanisms. To the best of our knowledge, this paper is the first of its kind considering the impact of the packet loss in designing packet marking scheme.

Ethernet passive optical network (EPON) is one of the potential solutions for the next generation access technology. Its economical equipment and maintenance costs are particularly attractive to telecommunication service providers. The EPON has a tree topology and the upstream bandwidth from optical network terminals to the optical line terminal is shared. To utilize the bandwidth in a fair and efficient manner, numerous dynamic bandwidth allocation schemes are proposed in the literature. In this paper, we will introduce and review these schemes, list their strength and weakness. One of our goals in this paper is to give an overview to the current status of research in this area. We will also introduce our preliminary work on a new scheme that consider performance guarantee on both bandwidth and delay. To our knowledge, this is the first attempt to provide absolute guarantee on both performance metrics in EPON. In conclusion, we summarize future works and point out the pending challenges for future study.

In this paper, we propose a new protection scheme named H at the ATM passive optical networks (APON) interface specifically for FTTH deployment. Compared with the APON interface protection schemes recommended in ITU G.983.1, the scheme H based on g*(1:n) protection at the optical line termination (OLT) is more economical. In order to speed up automatic protection switching, pre-ranging, and more importantly an innovative ranging algorithm called uni-ranging are developed. According to our investigation, such protection is suitable for an FTTH system in which the cost is the vital factor for successful and massive deployment.

The routing techniques used in conventional packet radio networks are not suitable for dynamic multihop wireless networks because of their unique architecture. In this paper a new hierarchical multihop routing algorithm is introduced which balances the cost of location-update and path-finding operations by partitioning the terminals and mobile base stations to produce a virtual topology. Based on the virtual topology each network entity stores a fraction of the network topology information and maintains the routing efficiency. Finally, the performance of the hierarchical multihop routing algorithm is investigated through simulations.

Low Earth Orbit (LEO) satellite networks require a reliable handover re-routing protocol that is critical for connections with multihop intersatellite links (ISLs). In this paper, we introduce a footprint handover re-route protocol (FHRP) that maintains the optimality of the initial route without performing a routing algorithm after satellite handovers. Furthermore, the FHRP handles the inter-orbit handover problem. The FHRP makes use of the footprints of the satellites in the initial route as the reference for re-routing. More specifically, after an optimum route has been determined during the call establishment process, the FHRP ensures that the new route due to handover is also optimum. The FHRP is applicable to any type of connectionoriented networks. The adaptation of the FHRP to the widely accepted ATM technology, which will be employed in future satellite networks, is also addressed in this paper. The FHRP demands easy processing, signaling, and storage costs. The performance re...

Unlike traditional data traffic, real time multimedia traffic requires synchronization. Temporal relationships among media must be maintained. Yet delay jitter and the absence of a global clock may disrupt these temporal relationships. This paper introduces new group synchronization protocols for real-time, multimedia applications, including teleconference, teleorchestration and multimedia on demand services. The proposed protocols achieve synchronization for all configurations (one-to-one, one-to-many, many-to-one, and many-to-many), and does so without prior knowledge of the end-to-end delay distribution, or the distribution of the clock drift. The only a-priori knowledge the protocols require is an upper bound on the end-to-end delay. The paper concludes with simulation experiments showing that the protocols work effectively in both LAN and WAN environments.