The University of Adelaide, School of Computer Science 15 January 2019 Optical Networks: A Practical Perspective, 3rd Edition Chapter 10 WDM Network Design Copyright © 2010, Elsevier Inc. All rights Reserved Chapter 2 — Instructions: Language of the Computer

Copyright © 2010, Elsevier Inc. All rights Reserved Figure 10.1 Chapter 10 Figure 10.1 (a) A three-node network. (b) Nodes A–B and B–C are interconnected by WDM links. All wavelengths are dropped and added at node B. (c) Half the wavelengths pass through optically at node B, reducing the number of router ports at node B. Copyright © 2010, Elsevier Inc. All rights Reserved

Copyright © 2010, Elsevier Inc. All rights Reserved Figure 10.2 Chapter 10 Figure 10.2 (a) The lightpath topology of the three-node network corresponding to Figure 10.1(a) that is seen by the routers. Routers A–B and B–C are connected by 10 parallel links. (b) The lightpath topology of the three-node network corresponding to Figure 10.1(b) that is seen by the routers. All pairs of routers, A–B, B–C, and C–A, are connected by 5 parallel links. Copyright © 2010, Elsevier Inc. All rights Reserved

Copyright © 2010, Elsevier Inc. All rights Reserved Figure 10.3 Chapter 10 Figure 10.3 Three different lightpath topologies that can be deployed over a fiber ring topology. (a) A point-to-point WDM ring where adjacent routers on the ring are connected by one or more lightpaths. (b) A hub topology where all routers are connected to one central router (hub) by lightpaths. (c) A full mesh where each router is connected to every other router by lightpaths. Copyright © 2010, Elsevier Inc. All rights Reserved

Copyright © 2010, Elsevier Inc. All rights Reserved Figure 10.4 Chapter 10 Figure 10.4 A PWDM ring architecture. The lightpaths and their wavelength assignment are shown in the figure for the case t = 3. Copyright © 2010, Elsevier Inc. All rights Reserved

Copyright © 2010, Elsevier Inc. All rights Reserved Figure 10.5 Chapter 10 Figure 10.5 A hubbed WDM ring architecture. The lightpaths and their wavelength assignment are shown in the figure for the case t = 1. Copyright © 2010, Elsevier Inc. All rights Reserved

Copyright © 2010, Elsevier Inc. All rights Reserved Figure 10.6 Chapter 10 Figure 10.6 An all-optical four-node network configuration. The lightpaths and their wavelength assignment are shown in the figure for the case t = 3. Copyright © 2010, Elsevier Inc. All rights Reserved

Copyright © 2010, Elsevier Inc. All rights Reserved Figure 10.7 Chapter 10 Figure 10.7 Number of IP router ports required for the different designs of Examples 10.2–10.4, for a ring with N = 8 nodes. The lower bound of t is also shown. Copyright © 2010, Elsevier Inc. All rights Reserved

Copyright © 2010, Elsevier Inc. All rights Reserved Figure 10.8 Chapter 10 Figure 10.8 Number of wavelengths required for the different designs of Examples 10.2–10.4, for a ring with N = 8 nodes. The lower bound from (10.10) is also shown. Copyright © 2010, Elsevier Inc. All rights Reserved

Copyright © 2010, Elsevier Inc. All rights Reserved Figure 10.9 Chapter 10 Figure 10.9 Shown is a network topology with link weights. There are two link disjoint paths between nodes A and D: (A,C,D) and (A,B,D). However, the simple method to compute disjoint paths fails. The method will first compute a shortest path (A,B,C,D), but then there is no second path that is disjoint from the first. Copyright © 2010, Elsevier Inc. All rights Reserved

Copyright © 2010, Elsevier Inc. All rights Reserved Figure 10.10 Chapter 10 Figure 10.10 A node with fixed-wavelength conversion capability. Signals entering at wavelength λ1 are converted to λ2 and vice versa. Signals entering at wavelength λ3 are converted to λ4 and vice versa. Copyright © 2010, Elsevier Inc. All rights Reserved

Copyright © 2010, Elsevier Inc. All rights Reserved Figure 10.11 Chapter 10 Figure 10.11 A node with limited wavelength conversion capability. Each input wavelength can be converted to one of two possible output wavelengths. Signals entering at wavelength λ1 or λ2 can be converted to λ3 or λ4. Signals entering at wavelength λ3 or λ4 can be converted to λ1 or λ2. Copyright © 2010, Elsevier Inc. All rights Reserved

Copyright © 2010, Elsevier Inc. All rights Reserved Figure 10.12 Chapter 10 Figure 10.12 The equivalence between multiple fiber networks and single fiber networks. Copyright © 2010, Elsevier Inc. All rights Reserved

Copyright © 2010, Elsevier Inc. All rights Reserved Figure 10.13 Chapter 10 Figure 10.13 An example to illustrate the difference between having and not having wavelength conversion. Copyright © 2010, Elsevier Inc. All rights Reserved

Copyright © 2010, Elsevier Inc. All rights Reserved Figure 10.14 Chapter 10 Figure 10.14 The three-node network of Figure 10.1(c) with the static OADM at the central node replaced by a reconfigurable OADM, or OXC. The OXC allows the set of lightpaths added/dropped at the node to be decided dynamically based on the lightpath/traffic requirements. Copyright © 2010, Elsevier Inc. All rights Reserved

Copyright © 2010, Elsevier Inc. All rights Reserved Figure 10.15 Chapter 10 Figure 10.15 A 20-node, 32-link network representing a skeleton of the ARPANET. An average of one lightpath request is assumed to arrive every month, between every pair of nodes, and this lightpath is assumed to be in place for an average of one year. The link capacities shown are calculated such that no link will need a capacity upgrade within two years, with high (85%) probability. Copyright © 2010, Elsevier Inc. All rights Reserved

Copyright © 2010, Elsevier Inc. All rights Reserved Figure 10.16 Chapter 10 Figure 10.16 Reuse factor plotted against the number of wavelengths for a 32-node random graph with average degree 4, with full wavelength conversion and no wavelength conversion, from [RS95]. The horizontal line indicates the value of the reuse factor that can be achieved with an infinite number of wavelengths with full wavelength conversion, which can be calculated analytically. Copyright © 2010, Elsevier Inc. All rights Reserved

Copyright © 2010, Elsevier Inc. All rights Reserved Figure 10.17 Chapter 10 Figure 10.17 Reuse factor plotted against the number of nodes for random graphs withaverage degree 4, with full wavelength conversion and no wavelength conversion (from [RS95]). Copyright © 2010, Elsevier Inc. All rights Reserved

Copyright © 2010, Elsevier Inc. All rights Reserved Figure 10.18 Chapter 10 Figure 10.18 (a) A line network with a set of lightpaths, also called an interval graph. (b) Wavelength assignment done by Algorithm 10.3. Copyright © 2010, Elsevier Inc. All rights Reserved

Copyright © 2010, Elsevier Inc. All rights Reserved Figure 10.19 Chapter 10 Figure 10.19 Wavelength assignment in a ring network. (a) A ring network and a set of lightpaths. (b) The ring is cut at a node that has a minimum number of lightpaths passing through it to yield a line network. (c) The lightpaths in the line network are assigned wavelengths according to Algorithm 10.3. The lightpaths going across the cut node are assigned separate additional wavelengths. Copyright © 2010, Elsevier Inc. All rights Reserved

Copyright © 2010, Elsevier Inc. All rights Reserved Figure 10.20 Chapter 10 Figure 10.20 A ring network with fixed-wavelength conversion at one node and no conversion at the others that is able to support lightpath requests with load L ≤ W − 1. One of the nodes is configured to convert wavelength i to wavelength (i + 1) mod W, and the other nodes provide no wavelength conversion. Copyright © 2010, Elsevier Inc. All rights Reserved

Copyright © 2010, Elsevier Inc. All rights Reserved Figure 10.21 Chapter 10 Figure 10.21 Two different scenarios of wavelength assignment in networks with bidirectional links. Copyright © 2010, Elsevier Inc. All rights Reserved

Copyright © 2010, Elsevier Inc. All rights Reserved Figure 10.22 Chapter 10 Figure 10.22 Network topology for Problem 10.26. Copyright © 2010, Elsevier Inc. All rights Reserved