Telcordia Technologies, Inc.

David F Shallcross

Hanan Luss

Komandur R Krishnan

Martin Eiger

Shoshana Loeb

Benjamin Falchuk

Janet L Jackel

Arnold Leslie Neidhardt

Joel Wright Gannett

Tamra Carpenter

George Lapiotis

Ann Von Lehmen

Shoshana K Loeb

Benjamin W Falchuk

A system and method for modeling and evaluating resource requirements of services is disclosed. The system and method in one aspect enable describing an application session in a software model, for example, as a sequence of events in a sequence diagram, annotating the sequence diagram with information and using the sequence diagram and the information to create a mathematical model such as a Markov model that represents the application session. Once in Markov form the service can be analyzed. The system may include a user interface for allowing a user to enter annotations to the sequence diagram.

Method for systematic modeling and evaluation of application flows

The design of telecommunication networks is such that there is provision of end-to-end path protection to multiple demands under a single link or node failure in the networks. Restoration routes are provided on Preconfigured Virtual Cycles (PVC's), where each demand is assigned one restoration route and specific restoration wavelengths on a segment of one cycle. Multiple demands may share restoration wavelengths, and the number of restoration wavelengths may vary among the PVC links. First, a plurality of candidate PVC's are generated where each demand may be assigned to multiple candidates. Assignment of demands with common failure scenarios are allowed, under certain conditions, to the same PVC. Next, a set of PVC's is selected from among the candidates, while minimizing total reserved restoration capacity and ensuring that all demands are protected. Next duplicate assignments are eliminated. Finally, conflicts of wavelength assignments are resolved. The invention focuses primarily on optical networks.

Network restoration under link or node failure using preconfigured virtual cycles

A computer implemented fault diagnosis method employing both probabilistic models and statistical learning that diagnoses faults using probabilities and time windows learned during the actual operation of a system being monitored. In a preferred embodiment, the method maintains for each possible root cause fault an a-priori probability that the fault will appear in a time window of specified length as well as maintaining&#x2014;for each possible resulting symptom(s)&#x2014;probabilities that the symptom(s) will appear in a time window containing the fault and probabilities that the alarm will not appear in a time window containing the fault. Consequently, the method according to the present invention may advantageously determine&#x2014;at any time&#x2014;the probability that a fault has occurred, and report faults which are sufficiently likely to have occurred. These probabilities are updated based upon past time windows in which we have determined fault(s) and their cause(s). Advantageously, each root cause fault may be assigned its own time window length. By maintaining these probability parameters for several different window lengths, a window length that is particularly well-suited to a particular set of conditions may be chosen.

Fault diagnosis employing probabilistic models and statistical learning

The design of optical telecommunication networks is such that there is provision of end-to-end path restoration to specified demands under up to two links or nodes failures. Restoration routes are provided on Path Protecting Preconfigured Cycles (PP-PCs), where each demand is assigned one or two restoration routes and restoration wavelengths on a segment of one cycle. Splitting of demand across multiple restoration routes is not allowed. All restoration routes and restoration wavelengths are predetermined where multiple demands may share restoration wavelengths without resorting to intermediate switching or wavelength conversions along restoration routes. First, numerous candidate PP-PCs are generated. Assignment of demands with common failure scenarios are allowed, under certain conditions, to the same PP-PC. Next, a set of PP-PCs is selected from among the candidates, while minimizing total reserved restoration wavelengths cost and ensuring that all demands are protected as required. Finally, conflicts of wavelength assignments are resolved.

Network restoration under dual failures using path protecting preconfigured cycles

A method for distributed computations for fault-diagnosis in a system whose fault propagation model has deterministic couplings between faults and symptoms includes creating a 'relation graph' in which the nodes correspond to the potential faults, with two nodes connected by a 'relational link' if their corresponding faults have an observed symptom in common. Each relational link is assigned a weight equal to the sum, taken over the symptoms represented by the relational link, of the reciprocal of the number of distinct fault-pairs that produce each such symptom. The relation graph is then partitioned into several domains, while minimizing the number of cross-domain relational links, which correspond to cross-domain symptoms. In each domain, all the optimal local solutions to the domain's sub-problem are first determined, and then a combination is selected of the local solutions, one from each domain, that explains the maximum number of cross-domain symptoms, where the optimal solution is supplemented, if necessary, with additional faults to explain any remaining unexplained cross-domain symptoms, determining also a bound on the deviation from optimality of the global solution.

Method for automated distributed diagnostics for networks

The present invention relates to a method and system for design and routing in telecommunications networks having transparent elements such as photonic switches. Transparent optical networks transmit signals optically, performing both switching and amplification photonically. As a result, transparent networks may be more economical than conventional 'opaque' optical networks that convert signals to electronic form at each network node because they do not require as much equipment for performing optical-electrical conversion. However, transparent networks pose new operational challenges. Physical-layer impairments that are repaired by optical-electrical-optical (OEO) regeneration can accumulate along (transparent) connection paths. To effectively deploy and utilize transparency, mechanisms to assure that impairment-feasible paths exist and can be identified in the network are required. The present invention provides: 1) a method for locating OEO-regeneration capability to assure the existence of impairment-feasible paths in a network and 2) a method for identifying impairment-feasible connection paths in a network of transparent and OEO-capable nodes. The first is a method related to network design, which models the design problem as a variation of a connected dominating set problem. The second is a method related to network routing, which transforms the impairment-aware routing problem into a shortest-path problem in an expanded network. The design methodology of the present invention employs both domination and connectability concepts to enable sparser placement of OEO regeneration capability within networks. Further, the routing methodology of the present invention provides a mechanism for finding feasible routes with respect to impairment constraints while minimizing the use of OEO interfaces to assure such feasibility.

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Piscataway, NJ, United States of America

David F Shallcross