T.-H. Wu, Fiber Network Service Survivability. Artech House, 1992.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....in a WDM network may affect upwards of a Terabit of traffic per second, motivates the study of WDM network survivability and reliability. The concept of survivable optical networks has been discussed extensively in [13 19] In addition, Path and link recovery schemes have also been researched in [20 22]. These studies have shown that path protection provides a better spare capacity utilization than link protection, but suffers from longer recovery times. We assume that the network is survivable or protected against any single link failure at the optical layer. In our work, such protection is ....

T. Wu, Fiber Network Service Survivability. Norwood, MA: Artech House, 1992.

....INTRODUCTION N ETWORK survivability techniques have been proposed to guarantee the seamless communication services in the face of network failures. Most techniques use centralized planning and are developed for circuit switched networks such as public switched telephone networks [1] SONET SDH [2], 3] 4] ATM [5] 6] 7] WDM networks [8] 9] However, circuitswitched backbone networks are being replaced or overlapped with packet switched networks which provide better manageability of bandwidth granularity and connection types. This architecture migration has been significantly ....

....noted otherwise. The network redundancy is measured by the ratio of the total spare capacity over the total working capacity. It depends highly on the network topology as well as the spare capacity allocation algorithms used. For example, a self healing ring (SHR) topology has 100 redundancy [2], 3] In mesh type networks, when working paths are the shortest hop paths, more than 100 redundancy is needed in reserving backup paths. However, the redundancy can be reduced by sharing spare capacity reservations and this reduction is feasible only when failure scenarios are non overlapping ....

Tsong-Ho Wu, Fiber Network Service Survivability, Artech House, 1992.

....optical networks has been discussed extensively in [ 1 3,11,12] In addition, in [4,5] the authors compared path and link protection restoration strategies by formulating their capacity requirements as an Integer Linear Program. Path and link recovery schemes have also been researched in [13 15]. These studies have shown that path protection provides a better spare capacity utilization than link protection, but suffers from longer recovery times. In [6] the authors proposed analytical methods to estimate capacity utilization in optical networks that are resilient to single link ....

T. Wu, Fiber Network Service Survivability. Norwood, MA: Artech House, 1992.

....is prepared to recover from failures but encounters instead an attack, it may malfunction and cause failures. A common recovery scheme is based on rings. We consider the two types of network restoration used for SONET SDH, the most common standards in use for highspeed optical communications [55]. Note that SONET SDH are not all optical standards, but the rates they support make their need for rapid service restoration commensurate with that of AONs. Speed of recovery with opto mechanical switches is in the tens of milliseconds and nanoseconds for acousto optical switches. SONET SDH allow ....

T.-H. Wu, Fiber Network Service Survivability, Artech House, 1992.

....algorithm has the potential of minimizing network cost both in terms of efficient use of fiber and reducing use of electronics. 5) Protection and Restoration: Various failures, such as fiber cuts, line card and switch failures, and software failures, can occur that disrupt network services [58]. Protection and restoration are two methods networks used to recover from these failures. Protection refers to hardware based, preplanned, fast failure recovery. Restoration refers to software based, dynamic, slower recovery. Protection is generally limited to simple topologies like rings or the ....

T.-H. Wu, Fiber Network Service Survivability. Norwood, MA: Artech House, 1992.

....of the failure and restoration reconfiguration. The generic term demand refers to a working unit of aggregated traffic to be transported between origin destination (O D) nodes of the network. The term follows Wu s distinction between traffic itself and the demand units required to transport it [15]. For example, traffic is the individual IP packet and or STS level tributary flows exchanged between O D pairs. But demand expresses the aggregate requirement of all traffic types for lightpaths between a given O D pair. One unit of demand consumes one working wavelength on each span traversed ....

T. S. Wu, Fiber Network Service Survivability, Artech House, 1992.

....The nodal elements of rings are relatively low cost add drop multiplexers (ADMs) An ADM has two optical line (e.g. OC 24, or OC 48 say) terminations and can originate (add) or terminate (drop) any of the tributary payload signals (e.g. STS 1 or DS3) from the line signal passing through it. See [2] for more on rings. The important point is that rings use a simple switching mechanism which permits restoration in about 50 60 ms, but they require at least 100 redundancy. In complete multi ring network designs the working fiber or channel groups themselves are usually not fully utilizable, so ....

T.-H. Wu, Fiber Network Service Survivability, Artech House, Boston, Mass.

....through pre planned cycles ( GS98] The most direct approach is to design the network in term of rings. The building blocks of SONET networks are generally self healing rings (SHRs) and diversity protection (DP) WCB91, Was91, WB90, SWC93, SGM93, SF96, STW95, GHS 94, WW92, TYKK94, Wu94, Wu92, WKC89, HT92] SHRs are unidirectional path switched rings (UPSRs) or bi directional line switched rings (BLSRs) while DP refers to physical redundancy where a spare link (node) is assigned to one or several links (nodes) Wu92] pp. 315 32) In rings, such as BLSR, link or node restoration is ....

.... WB90, SWC93, SGM93, SF96, STW95, GHS 94, WW92, TYKK94, Wu94, Wu92, WKC89, HT92] SHRs are unidirectional path switched rings (UPSRs) or bi directional line switched rings (BLSRs) while DP refers to physical redundancy where a spare link (node) is assigned to one or several links (nodes) Wu92] pp. 315 32) In rings, such as BLSR, link or node restoration is simply implemented using loop back. The waste of bandwidth due to back hauling may be remedied by looping back at points other than the failure location ( Mag97, KTK94] Using only DP and SHRs is a constraint which has cost ....

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T.H. Wu. Fiber Network Service Survivability. Artech House, 1992.

....INTRODUCTION N ETWORK survivability techniques have been proposed to guarantee the seamless communications services in the face of network failures. Most techniques use centralized planning and are developed for circuit switched networks such as public switched telephone networks [1] SONET SDH [2], 3] 4] ATM [5] 6] 7] WDM networks [8] 9] However, circuit switched backbone networks are being replaced or overlapped with packet switched networks which provide better manageability of bandwidth granularity and connection types. This architecture migration has been significantly ....

....noted otherwise. The network redundancy is measured by the ratio of the total spare capacity over the total working capacity. It depends highly on the network topology as well as the spare capacity allocation algorithms used. For example, a self healing ring (SHR) topology has 100 redundancy [2], 3] In mesh type networks, when working paths are the shortest hop paths, more than 100 redundancy is needed in reserving backup paths. However, the redundancy can be reduced by sharing spare capacity reservations and this reduction is feasible only when failure scenarios are non overlapping ....

Tsong-Ho Wu, Fiber Network Service Survivability, Artech House, 1992.

....(SCA) problem is to decide how much spare capacity should be reserved on network links for given traffic flows and their working paths on two connected mesh networks. It is part of survivable network design and is NP complete [1] Many research efforts on this issue has been done on SONET SDH [2], 3] 4] 5] ATM [6] 7] 8] 9] WDM networks [10] 11] 12] Recent issue on IP and MPLS networks are also given in [13] 14] 15] A detailed literature review on different spare capacity allocation algorithms and restoration schemes is given in [16] 1] In this paper, we first ....

Tsong-Ho Wu, Fiber Network Service Survivability, Artech House, 1992.

....are multiplexed and transported on a relatively sparse backbone of high capacity fiber optic transmission links. The impact of failure can be drastic [1] 2] There are currently two main approaches to provide a selfhealing capability for these networks. These are, generically, the ring [3] [11] and mesh [12] 20] restoration strategies. In a self healing mesh, demand flows are restored by agile re routing through the relatively small allocations of spare capacity on other spans of the network. Control of the process may be distributed [12] 14] 16] 18] or centralized [12] ....

....to offset the cost of the digital cross connect systems they use, making them effective in long haul networks. In comparison, rings require greater total capacity but reconfigure independently in a much simpler switching reaction and are based on less expensive add drop multiplexer (ADM) equipment [3] [7] Rings consequently Manuscript received June 6, 1996; revised February 1, 1998; approved by IEEE ACM TRANSACTIONS ON NETWORKING Editor K. S. Vastola. The author is with TRLabs, Edmonton, AB, Canada T5K 2P7 (e mail: grover edm.trlabs.ca) Publisher Item Identifier S 1063 6692(99)06391 8. ....

[Article contains additional citation context not shown here]

T. H. Wu, Fiber Network Service Survivability. Norwood, MA: Artech House, 1992.

....two seconds of outage, at which time switched and private line connections in progress are dropped by the circuit switches [1] Two seconds is therefore widely recognized as one significant real time target for restoration. Dedicated diverse routed fiber systems and protection switching rings [9] can restore service in 50 150 ms but represent an essentially fixed transport configuration to which the selforganizing methods that follow do not apply. In span restoration, signal replacement paths are formed between the end nodes of the span failure. The restoration path set is formed ....

T. H. Wu, Fiber Network Service Survivability. Norwood, MA: Artech House, 1992.

....20, 1999. The authors are with TRLabs and the Department of Electrical and Computer Engineering, University of Alberta, Edmonton, AB T5K 2P7, Canada (e mail: dstamate edm.trlabs.ca; grover edm.trlabs.ca) Publisher Item Identifier S 0090 6778(00)07098 7. 1 Bidirectional line switched ring (see [2]) set of experimental design trials were presented which showed, at least empirically, that optimized sets of p cycles could support 100 span restorability with very little or no spare capacity requirements beyond that of a theoretically minimal span restorable mesh network. The significance of ....

T. S. Wu, Fiber Network Service Survivability. Norwood, MA: Artech House, 1992.

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T.-H. Wu, Fiber Network Service Survivability. Artech House, 1992.

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T-H. Wu. Fiber Network Service Survivability. Artech House, Inc., Norwood, MA, 1992.

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T.H. Wu, "Fiber Network Service Survivability", 1992, Artech House, ISBN 0-89006-469-5

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T. H. Wu, Fiber Network Service Survivability, Artech House.

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T. Wu, Fiber Network Service Survivability, Artech House, 1992.

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T.-H. Wu. Fiber Network Service Survivability. Artech House, 1992.

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Tsong-Ho Wu. Fiber Network Service Survivability. Artech House, Inc., Norwood, MA, USA, 1992.

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T. Wu, Fiber Network Service Survivability, Norwood, MA: Artech House, 1992.

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T. Wu, Fiber Network Service Survivability. Norwood, MA: Artech House, 1992.

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T. Wu, Fiber Network Service Survivability, Norwood, MA: Artech House, 1992.

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Tsong-Ho Wu, Fiber Network Service Survivability, Artech House, Norwood, MA, 1992.

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T.-H. Wu (1992). Fiber Network Service Survivability. Artech House.

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