Dynamic Prioritization of Path for Quality-of-Service Differentiation in Multi-Priority Traffic

The emergence of value added services relying on a higher interactivity has altered the requirements of current transport network. Diverse traffic classes are processed by a large-scale optical network, imposing a more efficient utilization of their network infrastructure resources. Such services generally cross multiple domains, but inter-domain path computation algorithms still have some limitations. This paper describes a priority based path computation algorithm to meet all QoS requirements with the available capacity. The proposed algorithm increases the rate of successful replies while minimizing the blockage in network. The dynamic traffic is classified into high and low priority, so it improves emergency response in network

Shortest Constrained Inter-Domain Traffic Engineering Label Switched Paths Status of This Memo

This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards " (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited. Copyright Notice Copyright (c) 2009 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust’s Legal Provisions Relating to IETF Documents in effect on the date of publication of this documen

On the challenges of establishing disjoint QoS IP/MPLS paths across multiple domains

MPLS is being actively adopted as the core switching infrastructure at the intradomain level. This trend is mainly attributable to the undeniable potential of MPLS in terms of virtual private networks (VPNs) management, traffic engineering (TE), QoS delivery, path protection, and fast recovery from network failures. However, little progress has been made to attain the expected extension of MPLS label-switched paths (LSPs) across domain boundaries. Among the problems that remain unsolved is how to efficiently find and establish primary and protection interdomain LSPs for mission-critical services subject to QoS constraints. This article explores the major limitations hindering the deployment of these kinds of LSPs across multiple domains, in the context of the current interdomain network model. We describe the critical problems faced by the research community, and present our vision on how to rationally overcome some of the problems exposed. Our perspective is that we should be prepared for rather coarse-grained solutions as long as we need to coexist with the current interdomain network modelPostprint (published version

خوارزميات التوجية لأنظمة الإرسال المتعدد المستخدمة ضمن عناصر حساب المسار

The scalability and confidentiality constraints are particularly issues for the optimal point-to-point path computation in a multi-domain environment. Path Computation Element (PCE) has been proposed by Internet Engineering Task Force (IETF) to compute a network path or route based on a network graph and applying some constraints during the computation. In this paper, the major issues of supporting the multicast service in a multi-domain environment are discussed. Three investigated routing algorithms, which can be used by PCE, are proposed and investigated to compute multicast distribution trees in a multi-domain topology. These algorithms are Shortest Path in Each Domain (SPED), Shortest Path for All Domains 1 (SPAD1) and Shortest Path for All Domains 2 (SPAD2). At the end, the implementation and the performance evaluation of the investigated algorithms are given. We evaluate the performances of proposed algorithms by comparing different metrics, such as, the link resource usage, the node resource usage and the end-to-end hop count. From the results, we can see that the SPED algorithm is simple and its calculation time is short, but may not find the optimal end-to-end paths in multi-domain topologies. تُعَدّ قابلية التوسع (scalability) بالإضافة إلى قيود الوثوقية (confidentiality constraints) من أهم المعوقات التي تواجه طرق حساب المسار الأمثل بين عقدتين ضمن الشبكات المتعددة النطاقات. من أجل ذلك تم اقتراح وحدة حساب المسار (Path Computation Element PCE) من قبل الفريق الهندسي للانترنيت (Internet Engineering Task Force (IETF)) لحساب المسارات ضمن الشبكات اعتماداً على شكل وهيكلية الشبكة مع تطبيق بعض القيود في عملية الحساب. في هذه المقالة تمت مناقشة أهم المعوقات والمشاكل الناتجة عن استخدام خدمات أنظمة الإرسال المتعدد (Multicast) ضمن الشبكات المتعددة النطاقات. حيث تم اقتراح ودراسة ثلاث خوارزميات توجية والتي يمكن استخدامها في وحدة حساب المسار من أجل بناء شجرة التوزيع للأنظمة المتعددة الإرسال ضمن الشبكات المتعددة النطاقات. هذه الخوارزميات هي: خوارزمية حساب أقصر مسار في كل نطاق على حده (SPED)، خوارزمية حساب أقصر مسار في جميع النطاقات 1 (SPAD1) وخوارزمية حساب أقصر مسار في جميع النطاقات 2 (SPAD2). حيث تم محاكاة هذه الخوارزميات لدراسة وتقييم جودة أداء الخوارزميات المدروسة عن طريق مقارنتها باستخدام بارامترات تقييم مختلفة مثل: متوسط استخدام عناصر الشبكة سواء أسلاك الوصل أو العقد (الموجهات) و جودة المسار المحسوب بين نقطتي المصدر- المستقبل. بناءً على النتائج التي تم الحصول عليها نستطيع القول إن الخوارزمية (SPED) تعدّ من أبسط الخوارزميات والتي لا تحتاج إلى زمن طويل للقيام بعملية حساب المسار مقارنة مع الخوارزميات الأخرى المدروسة. هذه البساطة في الخوارزمية تؤدي إلى عدم إمكانية الحصول دائماً على المسار الأمثل بين نقطتي المصدر – المستقبل ضمن شبكات المتعددة النطاقات

Investigation on PCE-based multi-domain optical networks

The last decade has seen many advances in high-speed networking technologies. However, many issues are still open for the development of next generation optical transport networks in order to optimize the resources; this is especially true in the context of multi-domain optical networks. In this context, the IETF entity introduces the Path Computation Elements (PCE) module to improve the network resources occupation. In multi-domain networks, each network domain is usually owned by a different operator/administrator and it entails the reluctant behavior from some operators concerning the dissemination of intra-domain information. The purpose of this work is to present and compare different Traffic Engineering (TE) information dissemination strategies between PCEs in multi-domain optical networks. In such network context, recent studies have found that path computation only with local domain visibility yields poor network performance. Accordingly, certain visibility between domains seems necessary. Aiming to fit the confidentiality requirements of the composing domains and to improve the final network blocking probability, novel link aggregation techniques have been proposed. These techniques summarize the state of network domains resources efficiently. Besides, this aggregated link information is afterwards disseminated to all the remainder domains in the network. In order to fulfill this requirement, we introduce different update triggering policies to make a good trade-off between routing information scalability and inaccuracy. On the other hand, the IETF entity has defined several mechanisms (BRPC and H-PCE) for establishing inter-domain paths to compute routes through cooperation between PCEs. This master thesis proposes a hybrid path computation procedure based on the H-PCE and BRPC. It is important to highlight that the performance of all contributions has been supported by illustrative simulation results