Junling Yuan

A novel multicast routing algorithm in sparse splitting WDM network with power attenuation constraint

With the increasing requirement for communication bandwidth, all-optical network has been more and more important owning to its large traffic capability. Multicasting is an important technology in wavelength division multiplexing (WDM) optical network, and has been studied in many works. In this paper, we consider the multicasting technology on all-optical metropolitan area network (MAN) with maximum power attenuation constraint. The objective is to minimize total cost of a multicasting request. This problem is NP-hard. We propose a heuristic, named Power-Constraint Fix-Destination-Path (PC-FDP) algorithm, to solve this maximal power-loss constrained minimizing cost multicasting problem. It means that, during the process of building a multicasting tree, when a destination is reached and its power satisfies the constraint, the path from source to it would be fixed in the tree. Simulation results show that, all multicasting trees building the proposed algorithm satisfy the power constraint, with slight increasing of the total cost.

A subscription-based two-way signaling for optical burst switched networks

Optical burst switching (OBS) is a promising all-optical switching mechanism and signaling is one of the key technologies of optical burst switched networks. According to the propagation direction of control packets, an existing OBS signaling can be classified as one-way or two-way signaling. The transmission of bursts in two-way signaling is guaranteed while in one-way signaling is unguaranteed, so the blocking rate in two-way signaling is less than in one-way signaling. But the end-to-end delay and operation complexity in two-way is greater than in one-way signaling. In this paper, we propose another two-way signaling named subscription-based tell-and-wait (S-TAW), which is a forward reserved, delay-configured and implicitly released two-way OBS signaling. By analysis and simulation, we show that S-TAW can reduce the operation complexity and end-to-end delay without greatly increasing the blocking rate, comparing with the existing best-performed two-way signaling—prebooking reservation mechanism.

An improved multicast routing algorithm in sparse splitting optical networks

The construction of multicast light-trees in WDM network with sparse splitting has been proved to be an NP-complete problem. To reduce the diameter of the tree and average delay, an improved algorithm called Nearest Connector First Heuristic (NCFH) is proposed. The simulation results show that the proposed algorithm performs well.

An irregularly slotted ring scheme for contention-free optical burst switching

Optical burst switching (OBS) is a promising way to efficiently use the massive bandwidth in wavelength division multiplexing (WDM) networks. However, the problem of contention between bursts is hard to be solved in OBS networks with general topology. For that reason, the conception of contention-free OBS ring is proposed. In recent years, several OBS ring schemes have been designed. According to the number of transceivers installed at each node, the schemes can be roughly divided into two classes: single-transceiver schemes and multi-transceivers schemes. Among which, multi-transceivers schemes are more efficient than single-transceiver ones. There are two existing multi-transceivers schemes, LightRing and SWING, yet both of them have disadvantages. The LightRing scheme has a high queuing delay and needs large buffers, while the SWING scheme not only needs a large number of fiber delay lines but also has a specific requirement to the girth of the ring. In this paper, we design another multi-transceivers OBS ring scheme named irregularly slotted OBS ring (IS-OBS-Ring). In the IS-OBS-Ring scheme, all data wavelengths are slotted and slots on different wavelengths are not synchronously but irregularly distributed. Simulation results show that the performance of IS-OBS-Ring is further better than the LightRing scheme and similar to the SWING scheme. However, the IS-OBS-Ring scheme can overcome the disadvantages of both the LightRing scheme and the SWING scheme.

Inverse two-way signaling scheme for optical burst switched networks

Abstract Optical burst switching is a promising all-optical switching technology for the next generation optical networks and signaling is one of the key components of it. According to propagation direction of control packets, the existing signaling schemes for optical burst switched networks can be roughly divided into three categories: one-way, two-way, and hybrid signaling. Since one-way signaling launches bursts without the acknowledgment of successful reservation of resources, it has small end-to-end delay but high data loss rate; two-way signaling uses a control packet to gather the state of links and needs the successful acknowledgment before sending out a burst, so it has large end-to-end delay but low data loss rate. A hybrid signaling gets a tradeoff of performance between one-way and two-way signaling. In this paper, we propose another hybrid signaling named inverse two-way signaling. By introducing the process of link state collection into one-way signaling, the inverse two-way signaling can decrease the data loss rate without increasing the end-to-end delay compared to one-way signaling. In other words, the inverse two-way signaling is an improved version of one-way signaling.

Ellipse-underlay protection algorithm to deal with regional demolishments in mesh optical networks

For the abundant bandwidth, a malfunction in optical networks causes a great deal of loss to traffic, and hence the survivability of optical networks must be considered. Two technologies, protection and restoration, are used in general, and the former is investigated in this paper. The existing protection strategies mainly cope with a single link failure or a double-link failure in an optical network and not consider what causes these failures. In this paper, we study the reasons which lead to the network malfunctions, and pose a new concept named regional demolishment. A protection algorithm named Ellipse-underlay algorithm is also proposed. We compare the performance of the Ellipse-underlay algorithm to the Node-disjoint algorithm. Simulation results show that the Ellipse-underlay algorithm is more effective to the survivability of traffic than the Node-disjoint algorithm.

Hierarchical name system based on hybrid P2P for multimedia networks

Multimedia networks distribute multimedia resources to end users who can enjoy movie, music or photo via this platform. The name system is one of the most important elements in multimedia networks, for it defines how to name a resource and how to find it. Borrowing the idea of data-centric networking, this paper describes an approach which achieves the name system design criterion. In naming, a combination of three entities is used to achieve security, scalability, and flexibility. In name resolution, a three-layer structure is proposed to achieve precise and semantic resolutions. Then replication and cache scheme is proposed, and retrieval latency is analyzed. Numerical simulation shows the performance of designed name system.

EA-HD: a novel link state update mechanism for ASON

When a connection request comes in a mesh optical network, the routers automatically choose the suitable routing paths and wavelength to it according to the network topology and link-state information saved in its global link-state database. Because some of these wavelengths may be released or occupied at any time, the global state database is always out of date and need update by some update policy. A suitable link-state update policy is critical, since a high-frequency update policy imposes heavy burden on the network, while a low-frequency update would increase the inaccurate of the global link-state database. In this paper, we propose a link-state update policy, named the EA-HD policy, which considers two index of a link, one is the Hamming distance between the local link-state database and the global link-state database, and the other is the used ratio of its wavelengths. The proposed update policy gets a trade-off between the accurate of link-state information and its update cost. Simulation results prove that our scheme achieves a good performance in traffic blocking probability while maintaining moderate volume of update traffic.

A foresighted strategy for greed-based multicasting algorithms in all-optical mesh networks

For abundant bandwidth, all-optical mesh networks have been more and more important in communications, and multicasting is one of the key technologies to that. The problem to find a minimum multicasting tree is NP-hard, and all the existing algorithms are heuristics. Most of them are based on the idea of being greed. A greedy idea is always shortsighted. While it could get a good local effect, it would obtain a somewhat bad global performance. In this article, we propose a foresighted strategy for greed-based multicasting algorithms. With the co-action of the greedy idea and a foresighted strategy, a multicasting algorithm can get a good local and global performance simultaneously. We introduce the strategy by embedding it in the Member-Only algorithm and investigate two indexes, the average cost of all multicasting requests and the blocking rate of the whole network. Simulation results show that, with the presence of the proposed foresighted strategy, these two targets are all obviously decreased.