I. INTRODUCTION: Wavelength Division Multiplexing (WDM), also known as optical frequency division

600 WordsApr 23, 20193 Pages
I. INTRODUCTION: Wavelength Division Multiplexing (WDM), also known as optical frequency division multiplexing, is the use of multiple wavelengths to transfer the different data streams. In WDM, channel spacing’s are very larger than the information bandwidth of the signal. WDM is smart since the same fiber can be employed for multiple data streams, save the costs on fiber and installation. Since a huge bandwidth is available on fiber, WDM can provide an optical transmission system with an extremely large data rate: as of this writing, transmission systems with 50 wavelengths, each with a transmission rate of 10 Gb/s or higher, even for few seconds, means a huge waste of data information. As such, the WDM technology is very attractive for…show more content…
Hence these mechanisms of restoration scheme can’t guarantees for full recovery. And failures may result in large losses; protection schemes are generally favored in optical WDM mesh networks. Various protection mechanisms have been studied for WDM networks, including link based [3] and path based [4]. Link-based protection provides a backup for each link of a primary light-path. Hence, upon failure of a link, the end-nodes of the failed link activate the backup path and reroute the traffic around the failed link. Path- based protection; only one backup light-path is computed to protect all links in the primary light-path. Hence when a link fails here, notification messages are sent to the source and destination nodes in order to activate and reroute the traffic on the backup light-path. Path-based protection is usually more efficient in terms of capacity utilization, as compared to the link-based protection, i.e., since only one backup light-path is required to protect all links in the primary light-path. Indeed, many studies have already shown this result [5]. In addition, path-based approach can also protect all nodes in the primary light-path, except the source and destination nodes. By contrast, link-based protection is generally more resource-intensive and only provides “localized” protection. At the same time, this approach gives much faster recovery times. Path based protection schemes typically have high blocking probability than link based

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