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c e spectral width. NRZ modulation with spectral width. Figure 5.19 Chromatic dispersion limits on the distance and bit rate for transmission over standard single-mode fiber with a chromatic dispersion value of D. A chromatic dispersion penalty of 2 dB has been assumed in the NRZ case. this implies that the rms width of the dispersion-broadened pulse must lie within...
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The origin of PMD lies in the fact that different polarizations travel with different group velocities because of the ellipticity of the fiber core. Moreover, the distribution of signal energy over the different state of polarizations (SOPs) changes slowly with time, for example, because of changes in the ambient temperature. In addition to the fiber itself, PMD can arise from...
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To quantify the power penalty due to four-wave mixing, we will use the results of the analysis from [SBW87, SNIA90, TCF+95, OSYZ95]. This equation assumes a link of length L without any loss and chromatic dispersion.. Here Pi, Pj, and P~ denote the powers of the mixing waves and Pijk the power of the resulting new wave. In a real...
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DM soliton (5120 km). Figure 5.33 Typical contours of constant BER for a DM soliton and an NRZ modulated 10 Gb/s system. Another important factor influencing the performance of DM soliton systems is the peak-to-peak variation of the chromatic dispersion from the average over the span. In Figure 5.33, the peak-to-peak variation was chosen to be small (1.6 ps/nm-km), and...
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(a) You have a transmitter that operates at a wavelength of 1.55/~m, has a spec- tral width of I nm, and an output power of 0.5 mW. What is the length of the longest link that you can build?. (b) You have another transmitter that operates at a wavelength of 1.3/zm, has a spectral width of 2 nm, and an...
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Client Layers of the Optical Layer. These networks can be thought of as client layers of the optical layer. As we saw in Chapter 1, the optical layer provides lightpaths to the client layers. All the client layers that we will study process the data in the electrical domain, performing functions such as fixed time division multiplexing or statistical time...
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While SDH employs the same philosophy as SONET, there are some differ- ences in terminology and in the multiplexing structure for sub-STM-1 signals.. The functions of these layers will become clearer when we discuss the frame structure and overheads associated with each layer in the next section.. It is possible that intermediate nodes may do performance monitoring of the path...
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380 CLIENT LAYERS OF THE OPTICAL LAYER. In general, UPSRs are used in the access part of the network to connect multiple nodes to a hub node residing in a central office, and BLSRs are used in the interoffice part of the network to interconnect multiple central offices.. Another major component in the SONET infrastructure is a digital crossconnect (DCS)....
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IP was one of the earliest packet-switching protocols. IP transports information in the form of packets, which are of variable length. The routing table has one or more entries for each destination router in the network. The header contains the identity of the destination router for that packet. The router then does a lookup of its routing table to determine...
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400 CLIENT LAYERS OF THE OPTICAL LAYER. (b) Many SONET streams are to be multiplexed onto a higher-speed stream and transmitted over a SONET link.. (c) A fiber fails and SONET line terminals at the end of the link reroute all the traffic on the failed fiber onto another fiber.. (d) The error rate on a SONET link between regenerators...
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These transponders constitute a significant portion of the system cost.. Consider what is needed at node B. Therefore, six out of the eight transponders at node B are used to handle passthrough traffic--a very expensive proposition.. Consider the OADM solution shown in Figure 7.4(b). The network uses an OLT at nodes A and C and an OADM at node B....
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Figure 7.8 Using an OXC in the network. The OXC sits between the client equipment of the optical layer and the optical layer OLTs.. This capability becomes important when we deal with large numbers of wavelengths in a node or with a large number of nodes in the network. It also becomes important when the lightpaths in the network need...
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We also looked at reconfigurable OADM architectures, which use tunable filters and/or multiplexers, as well as tunable lasers, in order to provide the maximum possible flexibility in the network.. An optical crossconnect (OXC) is the other key network element in the optical layer. As with OADMs, several variants of OXCs exist, ranging from OXCs with electrical switch cores capable of...
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Figure 8.2 (a) The lightpath topology of the three-node network corresponding to Figure 8.1(a) that is seen by the routers. (b) The lightpath topology of the three-node network corresponding to Figure 8.1(b) that is seen by the routers. The task is to design a lightpath topology that interconnects the IP routers and to realize this topology within the optical layer....
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The solution to the lightpath topology design problem will specify which of the bij a r e 1 and which are 0. This is not a problem if the traffic is IP packets, but if we were instead considering SONET circuits, this is tantamount to assuming that the traffic between nodes consists of a large number of such circuits. Let...
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Figure 8.13 An example to illustrate the difference between having and not having wavelength conversion.. However, without wavelength conversion, the number of wavelengths required could be much larger. Example 8.6 Consider the network shown in Figure 8.13. The set of lightpath requests is shown in the figure to be the following. Transmitter ti must be con- nected to receiver r...
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Figure 8.18 Reuse factor plotted against the number of nodes for random graphs with average degree 4, with full wavelength conversion and no wavelength conversion (from [RS95]).. converters, the wavelength assignment algorithm assigns an arbitrary free wave- length on every link in the route to the lightpath. thus we assume full wavelength conversion. In both cases, if the wavelength assignment...
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480 W D M NETWORK DESIGN. Table 8.4 Number of wavelengths required to perform offline wavelength assign- ment as a function of the load L with and without wavelength converters. Other topologies such as star networks and tree networks have also been consid- ered in the literature. The same result can be extended to arbitrary networks where lightpaths are at...
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IEEE Transactions on Communications,. Topologies for high-speed optical networks. Heuristic algorithms for joint configuration of the optical and electrical layer in multi-hop wavelength routing networks. In Proceedings of IEEE Infocom, 2000.. Dynamic wavelengh allocation in all-optical ring networks. In Proceedings of IEEE International Conference on Communication, 1997.. In Proceedings of IEEE Infocom, 1999.. In Proceedings of IEEE Infocom, 1998.. Worst-case...
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Multiple types of shelves may be represented in the form of inherited object classes from the parent object shelf. Multiple types of line cards may be represented in the form of inherited object classes from the parent object line card. Each object has a variety of attributes associated with it, including the set of parameters that can be set by...