Single-link failure detection in all-optical networks using monitoring cycles and pa

[apala]

Single-Link Failure Detection in All-Optical Networks Using Monitoring Cycles and Paths

Abstract:

In this paper, we consider the problem of fault localization in all-optical networks. We introduce the concept of monitoring cycles (MCs) and monitoring paths (MPs) for unique identification of single-link failures. MCs and MPs are required to pass through one or more monitoring locations. They are constructed such that any single-link failure results in the failure of a unique combination of MCs and MPs that pass through the monitoring location(s). For a network with only one monitoring location, we prove that three-edge connectivity is a necessary and sufficient condition for constructing MCs that uniquely identify any single-link failure in the network. For this case, we formulate the problem of constructing MCs as an integer linear program (ILP).We also develop heuristic approaches for constructing MCs in the presence of one or more monitoring locations. For an arbitrary network (not necessarily three-edge connected), we describe a fault localization technique that uses both MPs and MCs and that employs multiple monitoring locations. We also provide a linear-time algorithm to compute the minimum number of required monitoring locations.Through extensive simulations, we demonstrate the effectiveness of the proposed monitoring technique.

Algorithm / Technique used:

Linear-time algorithm.


Existing System:

Optical networks have gained tremendous importance due to their ability to support very high data rates using the dense wavelength division multiplexing technology. With such high data rates, a brief service disruption in the operation of the network can result in the loss of a large amount of data. Commonly observed service disruptions are caused by fiber cuts, equipment failure, excessive bit errors, and human error. It is desired that these faults be uniquely identified and corrected at the physical layer before they are even noticed at higher layers. Therefore, it is critical for optical networks to employ fast and effective methods for identifying and locating network failures. Some failures, such as optical cross-connect port blocking and intrusion, can affect a single or a specific subset of wavelengths within a link. Other failures, including fiber cuts and high bit error rates (BERs), may affect all the wavelengths that pass through a fiber duct.

Proposed System:

In this work, we focus on the detection of the latter type of failures, and present a fault detection technique that can uniquely localize any single-link failure. For ease of explanation, we use the notion of failure, although the treatment applies as well to assessing other metrics that significantly impact the page link performance, such as optical power, optical signal-to-noise ratio (SNR), and BER. In order to rapidly measure the performance of a page link (or a collection of links), it is essential to analyze the signal in the optical domain via optical spectrum analyzers (monitors).
Various optical-level mechanisms for failure detection were proposed in the literature. These include optical spectral analysis, optical power detection, pilot tones, and optical time domain reflectometry (OTDR). a failure detection scheme was proposed, in which monitors are assigned to each optical multiplexing and transmission section.

Hardware Requirements:

System : Pentium IV 2.4 GHz.
Hard Disk : 40 GB.
Floppy Drive : 1.44 Mb.
Monitor : 15 VGA Colour.
Mouse : Logitech.
Ram : 256 Mb.

Software Requirements:

Operating system : - Windows XP Professional.
Front End : - Asp .Net 2.0.
Coding Language :- Visual C# .Net

read full report
http://ece.arizona.edu/ krunz/Papers/Journals/ToN_monitoring08.pdf

[dhaneesh]

The problem of fault localization in all-optical networks is considered here. The concept of monitoring cycles (MCs) and monitoring paths (MPs) are introduced for the purpose of unique identification of single-link failures. MCs and MPs pass through one or more monitoring locations. These monitoring locations are constructed such that any single-link failure results in the failure of a unique combination of MCs and MPs that pass through the monitoring location. three-edge connectivity is a necessary and sufficient condition for constructing MCs in the case of network with only one monitoring location. heuristic approaches for constructing MCs in the presence of one or more monitoring locations is developed and the problem of constructing MCs as an integer linear program (ILP) is formulated. a fault localization technique that uses both MPs and MCs and that employs multiple monitoring locations is described for an arbitrary network. a linear-time algorithm to compute the minimum number of required monitoring locations is also provided and the effectiveness of these techniques can be studied by simulation.

Achieving fast and precise failure localization has been a highly desired feature in all-optical mesh networks.M-trail (monitoring trail) has been proposed as the most general monitoring structure for achieving unambiguous failure localization of any single page link failure.

INTRODUCTION
Due to the lack of optoelectronic regenerators, the impact of a failure propagates without electronic boundary, and a single failure can trigger a large number of redundant alarms. One of the most commonly adopted approaches is to deploy optical monitors
responsible for generating alarms when a failure is detected.Conventional link-based monitoring scheme requires one monitor at each link. Monitoring-Trail (m-trail) along with an Integer Linear Program (ILP) for m-trail design, which was proved to yield better performance.

Briefs on Monitoring Trails (M-Trails)
an m-trail can traverse a node multiple times but a page link at most once.By allocating a sufficient number of m-trails, a routing entity in the network can localize a single failure by collecting the alarm signals of the monitors of m-trails.

Deployment of M-Trails
the target of m-trail design is to minimize the linear combination of monitoring cost and bandwidth cost. Total Cost = monitoring cost + bandwidth cost

Network Topology Diversity
m-trail solutions are affected by network topologies.

ALGORITHM FOR M-TRAIL SOLUTION
The proposed algorithm takes advantage of random code assignment (RCA) and random code swapping (RCS), aiming to overcome the topology diversity in general topologies.unique alarm codes are randomly assigned to each page link one after the other. Then m-trail formation is done by examining the connectivity of the links in each page link set. To improve the solution quality, RCS is performed to update the ACT for each page link set round by round.
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[poonam sonawane]

Single-link failure detection in all-optical networks using monitoring cycles and paths

In this paper, we consider the problem of fault localization in all-optical networks. We introduce the concept of monitoring cycles (MCs) and monitoring paths (MPs) for unique identification of single-link failures. MCs and MPs are required to pass through one or more monitoring locations. They are constructed such that any single-link failure results in the failure of a unique combination of MCs and MPs that pass through the monitoring location(s). For a network with only one monitoring location, we prove that three-edge connectivity is a necessary and sufficient condition for constructing MCs that uniquely identify any single-link failure in the network. For this case, we formulate the problem of constructing MCs as an integer linear program (ILP). We also develop heuristic approaches for constructing MCs in the presence of one or more monitoring locations. For an arbitrary network (not necessarily three-edge connected), we describe a fault localization technique that uses both MPs and MCs and that employs multiple monitoring locations. We also provide a linear-time algorithm to compute the minimum number of required monitoring locations. Through extensive simulations, we demonstrate the effectiveness of the proposed monitoring technique.

Technology to useOT NET