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![Figure 2.5: Traffic hierarchy defined in GMPLS ([79])](profile/R-Parthiban/publication/267973410/figure/fig3/AS:669411329454092@1536611506927/Traffic-hierarchy-defined-in-GMPLS-79_Q320.jpg)
![Figure 2.6: Client-Server Model ([46])](profile/R-Parthiban/publication/267973410/figure/fig4/AS:669411329449994@1536611506940/Client-Server-Model-46_Q320.jpg)
In this thesis, we present a framework to compare and evaluate alternative topologies and architectures for future optical backbone networks.
The most advanced form of currently deployed optical network, a point-topoint WDM network, has IP routers connected with Wavelength Division Multiplexed (WDM) links. A potential bottleneck in this type of ne...
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The traffic in metro and core networks is forecasted to grow in volume but also in dynamicity. Network operators dimension their optical networks and their IP edges for the expected traffic peak, and also reserve additional resources for the required survivability level. The latter is typically done by protection mechanisms at the optical or IP lay...
Citations
... Here, in contrast to the studies mentioned above, our survey differs in three significant aspects: First, this survey devotes greater attention to existing research efforts on reducing power consumption of the integrated core and metro networks (i.e., backbone network) [17]. The decision for this choice was based partly on predictions that the volume of global Internet traffic would exceed the zettabyte threshold [18], and on the knowledge that, at such high traffic volumes, power consumption of the backbone network is expected to surpass that of the access network [19]. ...
... Replacing a core router with an OXC is advantageous in eliminating the capacity bottleneck caused by electronic processing. Yet, the OXC fails to efficiently utilize available bandwidth when traffic arrives from the access networks at sub-wavelength granularity [17]. For example, in Fig. 3(b), the A-OCS network accommodates incoming traffic using 5 wavelengths instead of 2 wavelengths used in the PtP-WDM network (Fig. 3(a)). ...
... For example, in Fig. 3(b), the A-OCS network accommodates incoming traffic using 5 wavelengths instead of 2 wavelengths used in the PtP-WDM network (Fig. 3(a)). To increase bandwidth utilization, core nodes of OCS networks today are often provisioned with both core routers and OXCs [17] as illustrated in Fig. 3(c). Such OCS networks could be referred to as IP over Optical Transport Networks (IP-OTNs) [17]. ...
The year-by-year increase in electricity consumption significantly affects all nations today from environmental, social, and economic perspectives. Various studies show that, among the contributors of this increase, power consumption of the equipment forming the Internet infrastructure is significant. Consequently, considerable attention is given to finding solutions to reduce power consumption of the systems that run the Internet. Current literature suggests that the optical backbone network is responsible for the majority of the consumed power, particularly at high traffic loads. This highlights the importance of formulating solutions to reduce power consumption in backbone networks. In this paper, we provide a comprehensive survey of the most relevant research efforts on minimizing power consumption of backbone networks. We categorize our review into four broad approaches: network redesign, traffic engineering, power-aware networking, and load adaptive operation. We highlight the findings of relevant studies and provide an analysis of their limitations. We also evaluate the technological differences of similar work and identify a number of future directions. Finally, we demonstrate that the adoption of these technologies is gathering pace among prominent research bodies, device manufacturers, and network operators.
... Traffic grooming can be introduced in both the optical domain using waveband grooming, and in the IP domain using routers to aggregate traffic from multiple lightpaths [7]- [11]. However, the use of IP routers has an associated cost in terms of the number of Optical-to-Electrical-to-Optical (OEO) interfaces and router ports required [6], [12]. ...
... Its value can be derived using traffic measurements as in [34]. By examining the traffic added to and dropped from the core network by ERs, the number of ERs required in the network can be calculated as [6], [12], where is the capacity of an ER in bits/s and is a known parameter. The factor 2 is included in this expression to account for the incoming and outgoing traffic from an ER to the core network. ...
... We start by setting the add-drop ports per edge node . The number of edge nodes is inversely proportional to [6], [12]. For this reason, we vary the value of from the maximum number of ports per switch to 1 to find the minimum possible number of edge nodes. ...
This paper examines the economic viability of two technologies—optical circuit-switched (OCS) networks and op-tical burst-switched (OBS) networks—in the core network. We analyze and dimension OCS network (OCSN) and OBS network (OBSN) architectures for a range of traffic demands given the constraints on the network element capacities. We investigate the effect of traffic grooming for both of these architectures. We evaluate these network architectures for a national core network in Australia in terms of their capital costs and packet-blocking probabilities. We observe that OBSNs with traffic grooming at the optical layer may become more cost effective than OCSNs with traffic grooming at both the IP and optical layers for the same quality of service in terms of blocking probability. The cost advantage of OBSNs over OCSNs grows as the capacity of the core network increases. Hence, among the all-optical networking options that do not involve buffering at the core, OBS appears to be an attractive option especially for high-capacity core networks. Index Terms—IP aggregation, optical burst-swtiched (OBS), op-tical circuit-switched (OCS), traffic grooming, waveband, wave-length conversion.
... As well as reducing cost, one of the most important drivers behind wavelength routing (see [127, p. 507]) is the desire to reduce the processing overhead of pass-through traffic. In many applications, for example SONET or SDH networks, much of the electronic processing at an add-drop multiplexer (ADM) is dedicated to forwarding pass-through traffic that is not destined for the node in question, and thus an overhead saving is achieved if it can be forwarded optically [118]. ...
... As a final note on the topic of AON's, an evolution on the path of optical networking has been the introduction of control planes to support numerous improved features, such as fast and automated endto-end provisioning, fast and efficient re-routing, support for different client protocols (but optimized for IP), dynamic connection setup and support for differing levels of service quality [118]. This trend has been standardised by the International Telecommunications Union under the term automatically switched optical network or ASON [72]. ...
... This trend has been standardised by the International Telecommunications Union under the term automatically switched optical network or ASON [72]. ASONs include OXC's as switching components, but are not limited to purely optical networking, which reflects the reality of homogeneous networks in the real world [118]. We do not treat the topic further here, but refer the reader to overview paper [76]. ...
The increasing demand of future Internet traffic requires optical traffic grooming technology to reduce the complexity of the network. A network with optical cross connects and fibers has been considered as one potential architecture to achieve this goal. The design of this type of architecture involves determining the number of network components and the interconnection topology. In this paper we show that a hybrid ring-star topology and waveband grooming can help to reduce the network complexity. This helps us to minimize the number of nodes, and the number of ports required in each node. We develop an analytical method for the design of hybrid ring-star topology to reduce the capital cost of the overall optical network. We evaluate the performance of our method in terms of the number of network elements required for a national backbone network.
Over the last decade, the Internet traffic demand has been increasing exponentially. Optical networks are ideal to accommodate this increasing traffic demand. Optical Circuit Switched Network (OCSN) is an optical network architecture that allows for automatic switching of new traffic requests. This network consists of optical cross connects (OXCs), access routers, backbone IP routers, wavelength division multiplexed (WDM) links and other related network elements. Under traditional shortest path routing algorithms such as Dijkstra and Bellman-Ford, some links in this optical network can become congested due to too many requests passing through those links. In this scenario, re-routing of the data in the network becomes vital. Move to vacant wavelength retuning and Minimum overlapping to least congested wavelength reassignment are some of the existing wavelength re-routing techniques. In this paper, we develop a new re-routing algorithm that performs better than the existing technique in terms of reducing the number of blocked connections in an OCSN. We use Aurora 2008 software to evaluate this algorithm.
The increasing demand for Internet network capacity requires optical traffic-grooming technology to reduce the complexity of the network. A network with optical cross connects is one potential architecture to achieve this goal. We show that an alternate architecture based on a hybrid ring-star topology and waveband grooming helps to reduce the network complexity by minimizing the number of nodes and the number of ports required in each node. We develop an analytical method for the design of hybrid ring-star topologies to reduce the capital cost of the overall optical network. We evaluate the performance of our method in terms of the number of network elements required for a national backbone network and demonstrate its savings in comparison to waveband grooming.
This paper describes Aurora, a visualization tool capable of dimensioning and optimizing future optical network architectures. The tool is capable of modelling traffic, grooming traffic, routing lightpaths, assigning wavelengths, dimensioning networks and evaluating networks based on network cost for optical circuit-switched backbone networks. This tool compliments the tools that are available in the market and helps a network engineer to design an optical network from scratch. It also helps to compare the cost of various optical network architectures.
We investigate the optimal level of IP integration for the deployment of an automatically switched optical network (ASON). We design and analyze a national network delivering a high bandwidth access to every user, and investigate the capital cost of ASONs with IP routers. Based on this analysis, we show that an ASON with IP routers at the edge is more cost-effective than other alternatives.
We analyze the economic viability of 40 Gb/s deployment for an automatically switched optical network (ASON). We design and analyze a national network delivering a high bandwidth access to every user, and investigate the capital cost of a waveband groomed ASON for 10 Gb/s and 40 Gb/s. Based on this analysis, we show that the 40 Gb/s system is more cost-effective and scalable than the 10 Gb/s system
