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Unformatted text preview: 8.6 Configuration Management 493 8.6 Configuration Management We can break down configuration management functions into three parts: manag- ing the equipment in the network, managing the connections in the network, and managing the adaptation of client signals into the optical layer. 8.6.1 Equipment Management In general, the principles of managing optical networking equipment are no different from those of managing other high-speed networking equipment. We must be able to keep track of the actual equipment in the system (for example, number and location of optical line amplifiers) as well as the equipment in each network element and its capabilities. For example, in a terminal of a point-to-point WDM system, we may want to keep track of the maximum number of wavelengths and the number of wavelengths currently equipped, whether or not there are optical pre- and power amplifiers, and so forth. Among the considerations in designing network equipment is that we should be able to add to existing equipment in a modular fashion. For instance, we should be able to add additional wavelengths (up to a designed maximum number) without disrupting the operation of the existing wavelengths. Also, ideally the failure of one channel should not affect other channels, and the failed channel should be capable of being serviced without affecting the other channels. An issue that comes up in this regard is the use of arrayed multiwavelength components versus separate components for individual wavelengths, such as multiwavelength laser arrays instead of individual lasers for each wavelength. Using arrayed components can reduce the cost and footprint of the equipment. However, if one element in the array fails, the entire array will have to be replaced. This reduces the system availability, as replacing the array will involve disrupting the operation of multiple channels, and not just a single channel. Using arrays also increases the replacement cost of the module. Therefore there is always a trade-off between obtaining reduced cost and footprint on one front against system availability and replacement cost on the other front. We may also want to start out by deploying the equipment in the form of a point-to-point link and later upgrade it to handle ring or other network configura- tions. We may also desire ﬂexibility in associating specific port cards in the equipment with specific wavelengths. For example, it is better to have a system where we can choose the wavelength transmitted out of a port card independently of what slot it is located in. 494 Control and Management Another problem in WDM systems is the need to maintain an inventory of wavelength-specific spare cards. For example, each channel may be realized by using a card with a wavelength-specific laser in it. Thus you would need to stock spare cards for each wavelength. This can be avoided by using a wavelength-selectable (or tunable) laser on each card instead of a wavelength-specific laser....
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This note was uploaded on 01/15/2011 for the course ECE 6543 taught by Professor Boussert during the Spring '09 term at Georgia Tech.
- Spring '09