Steven G. Finn

All-Optical Network Consortium-ultrafast TDM networks

We describe recent results of the Advanced Research Projects Agency (ARPA) sponsored Consortium on Wideband All-Optical Networks which is developing architectures, technology components, and applications for ultrafast 100 Gb/s time-division multiplexing (TDM) optical networks. The shared-media ultrafast networks we envision are appropriate for providing low-access-delay bandwidth on demand to both future high-burst rate (100 Gb/s) users as well aggregates of lower-rate users (i.e., a heterogeneous user population). To realize these goals we are developing ultrafast network architectures such as HLAN, described here, that operate well in high-latency environments and require only limited processing capability at the ultrafast bit rates. We also describe results on 80-Gb/s, 90-km soliton transmission, 100-Gb/s soliton compression laser source technology, picosecond short-pulse fiber ring lasers, picosecond-accuracy optical bit-phase sensing and clock recovery, all-optical injection-locked fiber figure-eight laser clock recovery, short-pulse fiber loop storage, and all-optical pulse width and wavelength conversion.

Redundant trees for preplanned recovery in arbitrary vertex-redundant or edge-redundant graphs

We present a new algorithm which creates redundant trees on arbitrary node-redundant or link-redundant networks. These trees are such that any node is connected to the common root of the trees by at least one of the trees in case of node or link failure. Our scheme provides rapid preplanned recovery of communications with great flexibility in the topology design. Unlike previous algorithms, our algorithm can establish two redundant trees in the case of a node failing in the network. In the case of failure of a communications link, our algorithm provides a superset of the previously known trees.

A precompetitive consortium on wide-band all-optical networks

The technical core of a precompetitive consortium formed by AT&T, DEC, and MIT to study the technology, architecture and applications of wideband all-optical networks of local to national (or international) extent is described. A general introduction to all-optical networks is given, and some proposed applications are discussed. The architecture, technology and testbed portions of this effort are described. >

M/M/1 queues with working vacations (M/M/1/WV)

The classical single server vacation model is generalized to consider a server which works at a different rate rather than completely stops during the vacation period. Simple explicit formulae for the mean, variance, and distribution of the number and time in the system are presented. The distributional results generalize the classical vacation decomposition with no service during a vacation. This model approximates a multi-queue system whose service rate is one of the two speeds for which the fast speed mode cyclically moves from queue to queue with an exhaustive schedule. This work is motivated and illustrated by the analysis of a WDM optical access network using multiple wavelengths which can be reconfigured.

A wideband all-optical WDM network

We describe some of the results of the Advanced Research Projects Agency (ARPA) sponsored Consortium on Wideband All-Optical Networks in developing architectures, technology components, and applications for the realization of scaleable, wideband, and transparent optical wavelength-division multiplexing (WDM) networks. Our architecture addresses all-optical transport over the wide, metropolitan, and local areas. It utilizes wavelength partitioning, routing, and active multiwavelength cross-connect switches to achieve a network that is scaleable in the number of users, data rates, and geographic span. The network supports two services which can be point-to-multipoint or multipoint-to-multipoint simplex or duplex connections. The A service is a transparent physically circuit-switched service and the B-service is a scheduled time-slotted circuit which is transparent within its time slots. We have developed a 20-channel local and metropolitan area WDM testbed deployed in the Boston area, now undergoing characterization and experimental applications.

Security issues in all-optical networks

All-optical networks are emerging as a promising technology for terabit per second class communications. However, they are intrinsically different from electro-optical networks, particularly because they do not regenerate signals in the network. The characteristics of all-optical network components and architectures manifest new and still unstudied security vulnerabilities but also offer a new array of possible countermeasures. We focus on two types of attacks on the physical security of the network: service disruption, which prevents communication or degrades quality of service (QoS), and tapping, which compromises privacy by providing unauthorized users access to data which may be used for eavesdropping or traffic analysis.

Generalized loop-back recovery in optical mesh networks

Current means of providing loop-back recovery, which is widely used in SONET, rely on ring topologies, or on overlaying logical ring topologies upon physical meshes. Loop-back is desirable to provide rapid preplanned recovery of link or node failures in a bandwidth-efficient distributed manner. We introduce generalized loop-back, a novel scheme for performing loop-back in optical mesh networks. We present an algorithm to perform recovery for link failure and one to perform generalized loop-back recovery for node failure. We illustrate the operation of both algorithms, prove their validity, and present a network management protocol algorithm, which enables distributed operation for link or node failure. We present three different applications of generalized loop-back. First, we present heuristic algorithms for selecting recovery graphs, which maintain short maximum and average lengths of recovery paths. Second, we present WDM-based loop-back recovery for optical networks where wavelengths are used to back up other wavelengths. We compare, for WDM-based loop-back, the operation of generalized loop-back operation with known ring-based ways of providing loop-back recovery over mesh networks. Finally, we introduce the use of generalized loop-back to provide recovery in a way that allows dynamic choice of routes over preplanned directions.

WDM loop-back recovery in mesh networks

Current means of providing loop-back recovery, which is widely used in SONET, relies on fiber-based recovery, where a fiber is used to back up another fiber. We present WDM-based loop-back recovery for optical networks where wavelengths are used to back up other wavelengths. We present two new algorithms for performing WDM-based loop-back over optical mesh networks. The first algorithm performs recovery for link failures. We compare its operation with known ways of providing loop-back recovery and show that the known methods are not applicable to WDM-based recovery. The second algorithm performs WDM loop-back recovery for node failures. We illustrate the operation of both algorithms and prove their validity. We discuss the advantages of WDM-based loop-back for flexibility in WDM service provisioning.

A novel approach to automatic protection switching using trees

We propose a new algorithm for constructing redundant trees over any edge or node-redundant network in order to perform automatic protection switching in the presence of edge or node failures. Existing redundancy schemes and their topological requirements are reviewed. We describe our algorithm and give an overview of its essential properties. The algorithm is polynomial in the number of nodes. We present an example of the construction of a lowest cost redundant topology for a given configuration and of the operation of our algorithm on that topology. The algorithm is particularly well suited to multicast networks and optical networks, where trees may be created by signal splitting.

A new algorithm for bi-directional link self-healing for arbitrary redundant networks

Summary form only given. The bidirectional link self healing network (BLSN) automatic protection switching (APS) algorithm can protect arbitrary redundant networks from link and node failures by using loopback. This means that the more bandwidth efficient loopback APS method can be used to protect lowest cost redundant networks regardless of their topology.