Traffic Grooming Pada Jaringan Ring SONET DWDM

Suatu hal yang paling menjanjikan untuk jaringan masa depan yaitu jaringan DWDM (Dense Wavelength Division Multiplexing) terutama ketika diperlukan lebar pita yang cukup besar. Kapasitas transmisi dari suatu jaringan SONET (Synchronous Optical Network) telah mengalami peningkatan secara berarti berkaitan dengan penggunaan teknologi DWDM. Traffic grooming pada jaringan ring SONET DWDM merupakan pemecahan masalah packing traffic yang berbeda kecepatan menjadi beberapa aliran trafik pada ring DWDM dengan tujuan menghemat penggunaan perangkat SONET. Traffic grooming adalah proses pengelompokan beberapa jalur telekomunikasi, yang akan menentukan penggabungan aliran-aliran trafik di setiap node. Dalam tugas akhir ini akan disimulasikan perencanaan dari jaringan transport yang didasarkan pada jaringan ring SONET DWDM. Dalam kasus ini traffic grooming akan menentukan optimalisasi perencanaan jaringan ring SONET DWDM. RWA (Routing and Wavelength Assignment) akan menempatkan rute-rute trafik ke panjang gelombang tertentu sebagai cara untuk meminimalkan biaya keseluruhan dari penggunaan perangkat SADM (SONET Add/drop Multiplexers). Dengan masukan beberapa node serta jumlah trafik tiap node, sehingga akan didapatkan suatu alur jaringan ring SONET DWDM yang optimal sebagai cara untuk meminimalkan biaya keseluruhan dari perangkat SADM. Dari hasil pengujian, dapat disimpulkan bahwa tingkat penurunan jumlah pemakaian perangkat SADM terbesar ditunjukkan pada pengujian dengan masukan 25 node dan nilai rata-rata trafik 30 Gbps yaitu sebesar 73,33 %.. Tingkat penurunan jumlah pemakaian perangkat SADM terendah ditunjukkan pada pengujian dengan masukan 20 node dan nilai rata-rata trafik 10 Gbps yaitu sebesar 50,55 %. Kata kunci : traffic grooming, RWA, SONET, DWDM

Benchmarking and viability assessment of optical packet switching for metro networks

Optical packet switching (OPS) has been proposed as a strong candidate for future metro networks. This paper assesses the viability of an OPS-based ring architecture as proposed within the research project DAVID (Data And Voice Integration on DWDM), funded by the European Commission through the Information Society Technologies (IST) framework. Its feasibility is discussed from a physical-layer point of view, and its limitations in size are explored. Through dimensioning studies, we show that the proposed OPS architecture is competitive with respect to alternative metropolitan area network (MAN) approaches, including synchronous digital hierarchy, resilient packet rings (RPR), and star-based Ethernet. Finally, the proposed OPS architectures are discussed from a logical performance point of view, and a high-quality scheduling algorithm to control the packet-switching operations in the rings is explained

TOPOLOGICAL PLANNING OF COMMUNICATION NETWORKS

In this paper, we concentrate on topological planning process of large-scale communication networks such as those used by telecom operators. Such networks are usually spread over large geographical area, and finding an optimal topology is very important part of the planning process. Network equipment used in such network is very expensive, and two connection points can be hundreds of kilometers apart. These networks, in most cases, form a backbone network of telecom operator, meaning that majority of traffic is carried through high-speed communication links of such network. Any cable cuts or equipment malfunctions could result in huge data losses. Therefore, such networks require high degree of availability and fault resistance, which must be considered during the planning process. Network topology providing fault resistance should offer at least two separate communication paths between any pair of network nodes. Most important issue in network topology planning is finding topology with lowest possible overall network price, while keeping all requirements (such as fault tolerance, availability, maximal number of hops, maximal blocking probability etc.) satisfied. Network design process can be divided into three stages. First step is making decisions about which network elements (nodes, existing edges) should be included in a backbone network (for instance, one of sub-problems appearing in this phase is facility location problem). Second step includes selection of network topology, so that all elements selected in first step will be interconnected satisfying given requirements. Last phase is used to determine node and link capacities needed for successful traffic transport as well as routings of traffic demands, including protection. Depending on technologies used in network, different routing and protection mechanisms, as well as specific topology models, can be used (e.g. SDH/WDM SHR, mesh, dual-homing etc.)

Investigation of the tolerance of wavelength-routed optical networks to traffic load variations.

This thesis focuses on the performance of circuit-switched wavelength-routed optical network with unpredictable traffic pattern variations. This characteristic of optical networks is termed traffic forecast tolerance. First, the increasing volume and heterogeneous nature of data and voice traffic is discussed. The challenges in designing robust optical networks to handle unpredictable traffic statistics are described. Other work relating to the same research issues are discussed. A general methodology to quantify the traffic forecast tolerance of optical networks is presented. A traffic model is proposed to simulate dynamic, non-uniform loads, and used to test wavelength-routed optical networks considering numerous network topologies. The number of wavelengths required and the effect of the routing and wavelength allocation algorithm are investigated. A new method of quantifying the network tolerance is proposed, based on the calculation of the increase in the standard deviation of the blocking probabilities with increasing traffic load non-uniformity. The performance of different networks are calculated and compared. The relationship between physical features of the network topology and traffic forecast tolerance is investigated. A large number of randomly connected networks with different sizes were assessed. It is shown that the average lightpath length and the number of wavelengths required for full interconnection of the nodes in static operation both exhibit a strong correlation with the network tolerance, regardless of the degree of load non-uniformity. Finally, the impact of wavelength conversion on network tolerance is investigated. Wavelength conversion significantly increases the robustness of optical networks to unpredictable traffic variations. In particular, two sparse wavelength conversion schemes are compared and discussed: distributed wavelength conversion and localized wavelength conversion. It is found that the distributed wavelength conversion scheme outperforms localized wavelength conversion scheme, both with uniform loading and in terms of the network tolerance. The results described in this thesis can be used for the analysis and design of reliable WDM optical networks that are robust to future traffic demand variations

Use of Cross-Connect Clusters to Optimize Routing in Stm-64-Based Sdh Optical Network Systems

With the migration to Synchronous Digital Hierarchy, which uses the concept of logical rings, for backbone transmission systems, one of the major concerns that has been brought up repeatedly is a method in which to bring sub-rate circuits from one ring to another without having to decompose the entire backbone data stream to its individual circuits. This is critically important since the backbone data rate can be as high as 10 Gigabits per second or greater and may carry several thousand circuits, ranging in data rate from less than 2.4 Kilobits per second to 2.5 Gbps (STM-16). One potential means of providing this capability in cross-connection locations is to implement cross-connection clusters between the rings. This requires detailed planning of the network infrastructure prior to providing the first customer services, in order to avoid having disruptions to that service at a later date. As shown in this paper, the consequences for failing to plan and implement a strategy allowing for expansion and flexibility in the network build-out phases can have a significant impact in terms of revenue and reliability later during routine network operations, especially when service is needed for new customers

Using GRASP and GA to design resilient and cost-effective IP/MPLS networks

The main objective of this thesis is to find good quality solutions for representative instances of the problem of designing a resilient and low cost IP/MPLS network, to be deployed over an existing optical transport network. This research is motivated by two complementary real-world application cases, which comprise the most important commercial and academic networks of Uruguay. To achieve this goal, we performed an exhaustive analysis of existing models and technologies. From all of them we took elements that were contrasted with the particular requirements of our counterparts. We highlight among these requirements, the need of getting solutions transparently implementable over a heterogeneous network environment, which limit us to use widely standardized features of related technologies. We decided to create new models more suitable to fit these needs. These models are intrinsically hard to solve (NP-Hard). Thus we developed metaheuristic based algorithms to find solutions to these real-world instances. Evolutionary Algorithms and Greedy Randomized Adaptive Search Procedures obtained the best results. As it usually happens, real-world planning problems are surrounded by uncertainty. Therefore, we have worked closely with our counterparts to reduce the fuzziness upon data to a set of representative cases. They were combined with different strategies of design to get to scenarios, which were translated into instances of these problems. Finally, the algorithms were fed with this information, and from their outcome we derived our results and conclusions

Route recovery schemes for link and node failure and link congestion

Link/Node failure occurs frequently causing service disruption in computer networks. Hardware techniques have been developed to protect the network from Link/Node failure. These techniques work in physical layer, therefore their convergence time is very small. On the other hand, many schemes have been proposed to mitigate the failure influence on the network. These schemes work in upper layers such as the network layer. However, hardware solutions faster than other schemes, but they are expensive. Link/Node failure causes all flows which were using the failed link/node are temporarily interrupted till a new path reestablished. Three recovery algorithms have been proposed that mitigate the changes occur in the network. These changes are link/node failure and link congestion. The algorithms mainly pre-compute a backup next hop for each destination in the network. This path is feasible to accommodate re-routed traffic when a failure occurs without causing congestion or loops. Simulations have been conducted to show the performance of the proposed algorithms using ns2 network simulation tool. The results show fast recovery for all flows were using the link/node failure. Furthermore, the throughput per node also increases due to decrease interruption service time

An implementation of packet-switched communication for pilot protection at Tennessee Valley Authority

The utility network has long relied on Time Division Multiplexing (TDM) such as T1 and Synchronous Optical Network (SONET) as the main channel to transmit and receive data in a communication system. However, TDM technology is aging and its equipment becoming obsolete as vendors transition to Packet-Switched Networks (PSN) to make way for Ethernet-based network communications. Teleprotection is a critical element for a reliable power system as it provides high-speed tripping for faults on the protected line and is applied in various pilot protection schemes. Protection schemes cannot perform at their best without a fast and reliable communication system. The transition from a circuit-switched technology like SONET to a packet-based technology like Multiprotocol Label Switching-Transport Profile (MPLS-TP) has caused reservations for protection engineers as they express their concerns for lacking guaranteed 100% availability and potential latency. This paper will address this issue and the consistent test results at the Tennessee Valley Authority (TVA)\u27s lab have proven to satisfy the communication requirements in a teleprotection system. Teleprotection traffics make to its destination in order in microseconds, the symmetrical delay is less than 1µs, and especially the recovery from a failure occurs under 50ms (3 cycles). The results reassure the protection engineers that the Ethernet migration is necessary yet provides a better performance compared to the legacy system

Survivable mesh-network design & optimization to support multiple QoP service classes

Every second, vast amounts of data are transferred over communication systems around the world, and as a result, the demands on optical infrastructures are extending beyond the traditional, ring-based architecture. The range of content and services available from the Internet is increasing, and network operations are constantly under pressure to expand their optical networks in order to keep pace with the ever increasing demand for higher speed and more reliable links