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2015 | OriginalPaper | Buchkapitel

2. Failure Restoration Approaches

verfasst von : János Tapolcai, Pin-Han Ho, Péter Babarczi, Lajos Rónyai

Erschienen in: Internet Optical Infrastructure

Verlag: Springer New York

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Abstract

This chapter is on enumerating dynamic survivable routing schemes in mesh optical networks. By taking dynamic connection requests that arrive one after the other without any knowledge of future arrivals, the survivable routing schemes are required to allocate a disjoint working and protection path-pair for each connection request according to the current link-state. Without loss of generality, a working or a protection path is taken as a lightpath, either with a single wavelength if it is in a WDM network, or with some bandwidth allocated if it is in a spectrum-sliced elastic optical network supported by the optical orthogonal frequency division multiplexed technology.

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Literatur
2.
Zurück zum Zitat Andersen R, Chung F, Sen A, Xue G (2004) On disjoint path pairs with wavelength continuity constraint in wdm networks. In: Proceedings of the twenty-third annual joint conference of the IEEE computer and communications societies (INFOCOM), vol 1. IEEE, Hong Kong, China Andersen R, Chung F, Sen A, Xue G (2004) On disjoint path pairs with wavelength continuity constraint in wdm networks. In: Proceedings of the twenty-third annual joint conference of the IEEE computer and communications societies (INFOCOM), vol 1. IEEE, Hong Kong, China
3.
Zurück zum Zitat Babarczi P, Tapolcai J, Ho PH, Médard M (2012) Optimal dedicated protection approach to shared risk link group failures using network coding. In: Proceedings of the IEEE international conference on communications (ICC), pp 3051–3055 Babarczi P, Tapolcai J, Ho PH, Médard M (2012) Optimal dedicated protection approach to shared risk link group failures using network coding. In: Proceedings of the IEEE international conference on communications (ICC), pp 3051–3055
4.
Zurück zum Zitat Babarczi P, Biczók G, Overby H, Tapolcai J, Soproni P (2013) Realization strategies of dedicated path protection: a bandwidth cost perspective. Elsevier Comput Netw 57(9):1974–1990CrossRef Babarczi P, Biczók G, Overby H, Tapolcai J, Soproni P (2013) Realization strategies of dedicated path protection: a bandwidth cost perspective. Elsevier Comput Netw 57(9):1974–1990CrossRef
5.
Zurück zum Zitat Belzner M, Haunstein H (2009) Performance of network coding in transport networks with traffic protection. In: Proceedings of the ITG symposium on photonic networks. VDE, Vienna, Austria, pp 1–7 Belzner M, Haunstein H (2009) Performance of network coding in transport networks with traffic protection. In: Proceedings of the ITG symposium on photonic networks. VDE, Vienna, Austria, pp 1–7
6.
Zurück zum Zitat Bouillet E, Labourdette JF, Ellinas G, Ramamurthy R, Chaudhuri S (2002) Stochastic approaches to compute shared mesh restored lightpaths in optical network architectures. In: Proceedings of the twenty-first annual joint conference of the IEEE computer and communications societies (INFOCOM), vol 2. IEEE, New York, USA, pp 801–807 Bouillet E, Labourdette JF, Ellinas G, Ramamurthy R, Chaudhuri S (2002) Stochastic approaches to compute shared mesh restored lightpaths in optical network architectures. In: Proceedings of the twenty-first annual joint conference of the IEEE computer and communications societies (INFOCOM), vol 2. IEEE, New York, USA, pp 801–807
7.
Zurück zum Zitat Choi H, Subramaniam S, Choi H (2004) Loopback recovery from double-link failures in optical mesh networks. IEEE/ACM Trans Netw 12(6):1119–1130CrossRef Choi H, Subramaniam S, Choi H (2004) Loopback recovery from double-link failures in optical mesh networks. IEEE/ACM Trans Netw 12(6):1119–1130CrossRef
8.
Zurück zum Zitat Doucette J, He D, Grover WD, Yang O (2003) Algorithmic approaches for efficient enumeration of candidate p-cycles and capacitated p-cycle network design. In: Proceedings of the fourth international workshop on design of reliable communication networks (DRCN). IEEE, Banff, Alberta, Canada, pp 212–220 Doucette J, He D, Grover WD, Yang O (2003) Algorithmic approaches for efficient enumeration of candidate p-cycles and capacitated p-cycle network design. In: Proceedings of the fourth international workshop on design of reliable communication networks (DRCN). IEEE, Banff, Alberta, Canada, pp 212–220
9.
Zurück zum Zitat Ellinas G, Stern TE (1996) Automatic protection switching for link failures in optical networks with bi-directional links. In: Proceedings of the global telecommunications conference (GLOBECOM), communications: the key to global prosperity, vol 1. IEEE, London, UK, pp 152–156 Ellinas G, Stern TE (1996) Automatic protection switching for link failures in optical networks with bi-directional links. In: Proceedings of the global telecommunications conference (GLOBECOM), communications: the key to global prosperity, vol 1. IEEE, London, UK, pp 152–156
10.
Zurück zum Zitat Ellinas G, Hailemariam AG, Stern TE (2000) Protection cycles in mesh wdm networks. IEEE J Sel Areas Commun 18(10):1924–1937CrossRef Ellinas G, Hailemariam AG, Stern TE (2000) Protection cycles in mesh wdm networks. IEEE J Sel Areas Commun 18(10):1924–1937CrossRef
11.
Zurück zum Zitat Ellinas G, Bouillet E, Ramamurthy R, Labourdette JF, Chaudhuri S, Bala K (2003) Routing and restoration architectures in mesh optical networks. Opt Netw Mag 4(1):91–106 Ellinas G, Bouillet E, Ramamurthy R, Labourdette JF, Chaudhuri S, Bala K (2003) Routing and restoration architectures in mesh optical networks. Opt Netw Mag 4(1):91–106
12.
Zurück zum Zitat Frederick M, Datta P, Somani A (2006) Sub-graph routing: a generalized fault-tolerant strategy for link failures in wdm optical networks. Elsevier Comput Netw 50(2):181–199CrossRefMATH Frederick M, Datta P, Somani A (2006) Sub-graph routing: a generalized fault-tolerant strategy for link failures in wdm optical networks. Elsevier Comput Netw 50(2):181–199CrossRefMATH
13.
Zurück zum Zitat Grover WD (2003) Mesh-based survivable networks: options and strategies for optical, MPLS, SONET and ATM networking. Prentice Hall PTR, Upper Saddle River Grover WD (2003) Mesh-based survivable networks: options and strategies for optical, MPLS, SONET and ATM networking. Prentice Hall PTR, Upper Saddle River
14.
Zurück zum Zitat Grover WD, Doucette J (2002) Advances in optical network design with p-cycles: joint optimization and pre-selection of candidate p-cycles. In: Proceedings of the existing and emerging architecture and applications/dynamic enablers of next-generation optical communications systems/fast optical processing in optical transmission/VCSEL and all-optical networking. IEEE, IEEE-LEOS Summer Tropical Meetings, Mont Tremblant, Quebec, Canada, pp WA2–WA49 Grover WD, Doucette J (2002) Advances in optical network design with p-cycles: joint optimization and pre-selection of candidate p-cycles. In: Proceedings of the existing and emerging architecture and applications/dynamic enablers of next-generation optical communications systems/fast optical processing in optical transmission/VCSEL and all-optical networking. IEEE, IEEE-LEOS Summer Tropical Meetings, Mont Tremblant, Quebec, Canada, pp WA2–WA49
15.
Zurück zum Zitat Grover WD, Stamatelakis D (1998) Cycle-oriented distributed preconfiguration: ring-like speed with mesh-like capacity for self-planning network restoration. In: Proceedings of the international conference on communications (ICC), vol 1. IEEE, Atlanta, Georgia, USA, pp 537–543 Grover WD, Stamatelakis D (1998) Cycle-oriented distributed preconfiguration: ring-like speed with mesh-like capacity for self-planning network restoration. In: Proceedings of the international conference on communications (ICC), vol 1. IEEE, Atlanta, Georgia, USA, pp 537–543
16.
Zurück zum Zitat Grover W, Doucette J, Clouqueur M, Leung D, Stamatelakis D (2002) New options and insights for survivable transport networks. IEEE Commun Mag 40(1):34–41CrossRef Grover W, Doucette J, Clouqueur M, Leung D, Stamatelakis D (2002) New options and insights for survivable transport networks. IEEE Commun Mag 40(1):34–41CrossRef
17.
Zurück zum Zitat Herzberg M, Bye SJ (1994) An optimal spare-capacity assignment model for survivable networks with hop limits. In: Proceedings of the global telecommunications conference (GLOBECOM), communications: the global bridge, vol 3. IEEE, San Francisco, California, USA, pp 1601–1606 Herzberg M, Bye SJ (1994) An optimal spare-capacity assignment model for survivable networks with hop limits. In: Proceedings of the global telecommunications conference (GLOBECOM), communications: the global bridge, vol 3. IEEE, San Francisco, California, USA, pp 1601–1606
18.
Zurück zum Zitat Ho PH, Mouftah H (2001) Issues on diverse routing for wdm mesh networks with survivability. In: Proceedings of the tenth international conference on computer communications and networks (ICCCN). IEEE, Scottsdale, Arizona, USA, pp 61–66 Ho PH, Mouftah H (2001) Issues on diverse routing for wdm mesh networks with survivability. In: Proceedings of the tenth international conference on computer communications and networks (ICCCN). IEEE, Scottsdale, Arizona, USA, pp 61–66
19.
Zurück zum Zitat Ho PH, Mouftah HT (2002) A framework for service-guaranteed shared protection in wdm mesh networks. IEEE Commun Mag 40(2):97–103CrossRefMATH Ho PH, Mouftah HT (2002) A framework for service-guaranteed shared protection in wdm mesh networks. IEEE Commun Mag 40(2):97–103CrossRefMATH
20.
Zurück zum Zitat Ho PH, Mouftah HT (2004) A novel survivable routing algorithm for shared segment protection in mesh wdm networks with partial wavelength conversion. IEEE J Sel Areas Commun 22(8):1548–1560CrossRef Ho PH, Mouftah HT (2004) A novel survivable routing algorithm for shared segment protection in mesh wdm networks with partial wavelength conversion. IEEE J Sel Areas Commun 22(8):1548–1560CrossRef
21.
Zurück zum Zitat Ho PH, Tapolcai J, Cinkler T (2004) Segment shared protection in mesh communications networks with bandwidth guaranteed tunnels. IEEE/ACM Trans Netw 12(6):1105–1118CrossRef Ho PH, Tapolcai J, Cinkler T (2004) Segment shared protection in mesh communications networks with bandwidth guaranteed tunnels. IEEE/ACM Trans Netw 12(6):1105–1118CrossRef
22.
Zurück zum Zitat Ho PH, Tapolcai J, Mouftah HT (2004) On achieving optimal survivable routing for shared protection in survivable next-generation internet. IEEE Trans Reliab 53(2):216–225CrossRef Ho PH, Tapolcai J, Mouftah HT (2004) On achieving optimal survivable routing for shared protection in survivable next-generation internet. IEEE Trans Reliab 53(2):216–225CrossRef
23.
Zurück zum Zitat Hu JQ (2003) Diverse routing in optical mesh networks. IEEE Trans Commun 51(3):489–494CrossRef Hu JQ (2003) Diverse routing in optical mesh networks. IEEE Trans Commun 51(3):489–494CrossRef
24.
Zurück zum Zitat Iraschko RR, MacGregor M, Grover WD (1998) Optimal capacity placement for path restoration in STM or ATN mesh-survivable networks. IEEE/ACM Trans Netw 6(3):325–336CrossRef Iraschko RR, MacGregor M, Grover WD (1998) Optimal capacity placement for path restoration in STM or ATN mesh-survivable networks. IEEE/ACM Trans Netw 6(3):325–336CrossRef
25.
Zurück zum Zitat Kodialam M, Lakshman T (2001) Dynamic routing of locally restorable bandwidth guaranteed tunnels using aggregated link usage information. In: Proceedings of the twentieth annual joint conference of the IEEE computer and communications societies (INFOCOM), vol 1. IEEE, Anchorage, Alaska, USA, pp 376–385 Kodialam M, Lakshman T (2001) Dynamic routing of locally restorable bandwidth guaranteed tunnels using aggregated link usage information. In: Proceedings of the twentieth annual joint conference of the IEEE computer and communications societies (INFOCOM), vol 1. IEEE, Anchorage, Alaska, USA, pp 376–385
27.
Zurück zum Zitat Liu C, Ruan L (2004) Finding good candidate cycles for efficient p-cycle network design. In: Proceedings of the 13th international conference on computer communications and networks (ICCCN). IEEE, Chicago, IL, USA, pp 321–326 Liu C, Ruan L (2004) Finding good candidate cycles for efficient p-cycle network design. In: Proceedings of the 13th international conference on computer communications and networks (ICCCN). IEEE, Chicago, IL, USA, pp 321–326
28.
Zurück zum Zitat Liu Y, Tipper D, Siripongwutikorn P (2005) Approximating optimal spare capacity allocation by successive survivable routing. IEEE/ACM Trans Netw 13(1):198–211CrossRef Liu Y, Tipper D, Siripongwutikorn P (2005) Approximating optimal spare capacity allocation by successive survivable routing. IEEE/ACM Trans Netw 13(1):198–211CrossRef
29.
Zurück zum Zitat Nguyen HN, Habibi D, Phung VQ, Lachowicz S, Lo K, Kang B (2006) Qrp02-5: joint optimization in capacity design of networks with p-cycle using the fundamental cycle set. In: Proceedings of the global telecommunications conference (GLOBECOM). IEEE, San Francisco, California, USA, pp 1–5 Nguyen HN, Habibi D, Phung VQ, Lachowicz S, Lo K, Kang B (2006) Qrp02-5: joint optimization in capacity design of networks with p-cycle using the fundamental cycle set. In: Proceedings of the global telecommunications conference (GLOBECOM). IEEE, San Francisco, California, USA, pp 1–5
30.
Zurück zum Zitat Øverby H (2006) Cost evaluations of the protected network layer packet redundancy scheme. J Opt Netw 5(10):747–763CrossRef Øverby H (2006) Cost evaluations of the protected network layer packet redundancy scheme. J Opt Netw 5(10):747–763CrossRef
31.
Zurück zum Zitat Pióro M, Medhi D (2004) Routing, flow, and capacity design in communication and computer networks. The Morgan Kaufmann series in networking, Morgan Kaufmann Publishers/ElsevierMATH Pióro M, Medhi D (2004) Routing, flow, and capacity design in communication and computer networks. The Morgan Kaufmann series in networking, Morgan Kaufmann Publishers/ElsevierMATH
32.
Zurück zum Zitat Qiao C, Yoo M (1999) Optical burst switching (obs)—a new paradigm for an optical internetˆ{1}. J High Speed Netw 8(1):69–84 Qiao C, Yoo M (1999) Optical burst switching (obs)—a new paradigm for an optical internetˆ{1}. J High Speed Netw 8(1):69–84
33.
Zurück zum Zitat Ramamurthy S, Mukherjee B (1999) Survivable wdm mesh networks. II. Restoration. In: Proceedings of the IEEE international conference on communications (ICC), vol 3. IEEE, Vancouver, British Columbia, Canada, pp 2023–2030 Ramamurthy S, Mukherjee B (1999) Survivable wdm mesh networks. II. Restoration. In: Proceedings of the IEEE international conference on communications (ICC), vol 3. IEEE, Vancouver, British Columbia, Canada, pp 2023–2030
34.
Zurück zum Zitat Ramasubramanian S, Harjani A (2006) Comparison of failure dependent protection strategies in optical networks. Photonic Netw Commun 12(2):195–210CrossRef Ramasubramanian S, Harjani A (2006) Comparison of failure dependent protection strategies in optical networks. Photonic Netw Commun 12(2):195–210CrossRef
35.
Zurück zum Zitat Saradhi CV, Murthy CSR (2002) Dynamic establishment of segmented protection paths in single and multi-fiber wdm mesh networks. In: The convergence of information technologies and communications. International Society for Optics and Photonics, Boston, MA, USA, pp 211–222 Saradhi CV, Murthy CSR (2002) Dynamic establishment of segmented protection paths in single and multi-fiber wdm mesh networks. In: The convergence of information technologies and communications. International Society for Optics and Photonics, Boston, MA, USA, pp 211–222
36.
Zurück zum Zitat Schupke D (2004) An ilp for optimal p-cycle selection without cycle enumeration. In: Proceedings of the eighth working conference on optical network design and modelling Schupke D (2004) An ilp for optimal p-cycle selection without cycle enumeration. In: Proceedings of the eighth working conference on optical network design and modelling
37.
Zurück zum Zitat Stamatelakis D, Grover WD (2000) Network restorability design using pre-configured trees, cycles, and mixtures of pattern types. TRLabs, Edmonton. Tech. Rep. TR-1999-05 Stamatelakis D, Grover WD (2000) Network restorability design using pre-configured trees, cycles, and mixtures of pattern types. TRLabs, Edmonton. Tech. Rep. TR-1999-05
38.
Zurück zum Zitat Su X, Su CF (2001) An online distributed protection algorithm in wdm networks. In: Proceedings of the IEEE international conference on communications (ICC), vol 5. IEEE, Helsinki, Finland, pp 1571–1575 Su X, Su CF (2001) An online distributed protection algorithm in wdm networks. In: Proceedings of the IEEE international conference on communications (ICC), vol 5. IEEE, Helsinki, Finland, pp 1571–1575
39.
41.
Zurück zum Zitat Wang D, Li G (2008) Efficient distributed bandwidth management for mpls fast reroute. IEEE/ACM Trans Netw 16(2):486–495CrossRef Wang D, Li G (2008) Efficient distributed bandwidth management for mpls fast reroute. IEEE/ACM Trans Netw 16(2):486–495CrossRef
42.
Zurück zum Zitat Wang H, Modiano E, Médard M (2002) Partial path protection for wdm networks: end-to-end recovery using local failure information. In: Proceedings of the seventh international symposium on computers and communications (ISCC). IEEE, Taormina, Italy, pp 719–725 Wang H, Modiano E, Médard M (2002) Partial path protection for wdm networks: end-to-end recovery using local failure information. In: Proceedings of the seventh international symposium on computers and communications (ISCC). IEEE, Taormina, Italy, pp 719–725
43.
Zurück zum Zitat Wasem OJ (1991) An algorithm for designing rings for survivable fiber networks. IEEE Trans Reliab 40(4):428–432CrossRefMATH Wasem OJ (1991) An algorithm for designing rings for survivable fiber networks. IEEE Trans Reliab 40(4):428–432CrossRefMATH
44.
Zurück zum Zitat Wasem OJ (1991) Optimal topologies for survivable fiber optic networks using sonet self-healing rings. In: Proceedings of the global telecommunications conference (GLOBECOM), countdown to the new millennium. Featuring a mini-theme on: personal communications services. IEEE, Phoenix, Arizona, USA, pp 2032–2038 Wasem OJ (1991) Optimal topologies for survivable fiber optic networks using sonet self-healing rings. In: Proceedings of the global telecommunications conference (GLOBECOM), countdown to the new millennium. Featuring a mini-theme on: personal communications services. IEEE, Phoenix, Arizona, USA, pp 2032–2038
45.
Zurück zum Zitat Wu B, Yeung K, Ho PH (2010) Ilp formulations for p-cycle design without candidate cycle enumeration. IEEE/ACM Trans Netw 18(1):284–295CrossRef Wu B, Yeung K, Ho PH (2010) Ilp formulations for p-cycle design without candidate cycle enumeration. IEEE/ACM Trans Netw 18(1):284–295CrossRef
46.
Zurück zum Zitat Xin C, Ye Y, Dixit S, Qiao C (2001) Joint lightpath routing approach in survivable optical networks. In: Proceedings of the Asia-Pacific optical and wireless communications conference and exhibit. International Society for Optics and Photonics, Beijing, China, pp 139–146 Xin C, Ye Y, Dixit S, Qiao C (2001) Joint lightpath routing approach in survivable optical networks. In: Proceedings of the Asia-Pacific optical and wireless communications conference and exhibit. International Society for Optics and Photonics, Beijing, China, pp 139–146
47.
Zurück zum Zitat Xiong Y, Mason LG (1999) Restoration strategies and spare capacity requirements in self-healing atm networks. IEEE/ACM Trans Netw 7(1):98–110CrossRef Xiong Y, Mason LG (1999) Restoration strategies and spare capacity requirements in self-healing atm networks. IEEE/ACM Trans Netw 7(1):98–110CrossRef
48.
Zurück zum Zitat Xu D, Qiao C, Xiong Y (2002) An ultra-fast shared path protection scheme-distributed partial information management, part ii. In: Proceedings of the 10th IEEE international conference on network protocols (ICNP). IEEE, Paris, France, pp 344–353 Xu D, Qiao C, Xiong Y (2002) An ultra-fast shared path protection scheme-distributed partial information management, part ii. In: Proceedings of the 10th IEEE international conference on network protocols (ICNP). IEEE, Paris, France, pp 344–353
49.
Zurück zum Zitat Xu D, Xiong Y, Qiao C (2003) Protection with multi-segments (promise) in networks with shared risk link groups (srlg). In: Proceedings of the annual Allerton conference on communication control and computing, 1998, vol 40. The University, IEEE/ACM Transaction on Networking, 11(2):248–258 Xu D, Xiong Y, Qiao C (2003) Protection with multi-segments (promise) in networks with shared risk link groups (srlg). In: Proceedings of the annual Allerton conference on communication control and computing, 1998, vol 40. The University, IEEE/ACM Transaction on Networking, 11(2):248–258
50.
Zurück zum Zitat Xu D, Chen Y, Xiong Y, Qiao C, He X (2006) On the complexity of and algorithms for finding the shortest path with a disjoint counterpart. IEEE/ACM Trans Netw 14(1):147–158CrossRef Xu D, Chen Y, Xiong Y, Qiao C, He X (2006) On the complexity of and algorithms for finding the shortest path with a disjoint counterpart. IEEE/ACM Trans Netw 14(1):147–158CrossRef
51.
Zurück zum Zitat Yuan S, Jue JP et al (2002) Shared protection routing algorithm for optical network. Opt Netw Mag 3(3):32–39 Yuan S, Jue JP et al (2002) Shared protection routing algorithm for optical network. Opt Netw Mag 3(3):32–39
52.
Zurück zum Zitat Zhang H, Yang O (2002) Finding protection cycles in dwdm networks. In: International conference on network protocols IEEE international conference on communications (ICC), vol 5. IEEE, New York, USA, pp 2756–2760 Zhang H, Yang O (2002) Finding protection cycles in dwdm networks. In: International conference on network protocols IEEE international conference on communications (ICC), vol 5. IEEE, New York, USA, pp 2756–2760
Metadaten
Titel
Failure Restoration Approaches
verfasst von
János Tapolcai
Pin-Han Ho
Péter Babarczi
Lajos Rónyai
Copyright-Jahr
2015
Verlag
Springer New York
DOI
https://doi.org/10.1007/978-1-4614-7738-9_2

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