Design of a meta-mesh of chain subnetworks: enhancing the attractiveness of mesh-restorable WDM networking on low connectivity graphs

Grover, W.D.; Doucette, John

doi:10.1109/49.974661

Cited by 33 publications

(21 citation statements)

References 19 publications

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“…Although this seems counter-intuitive at first, [14] explains that each bypass creates a specific form of dispersal of the end nodes involved in logical span restoration, resulting in more efficient spare capacity use. This is ultimately the same reason for the reduction of spare capacity obtained with the special forms of chain sub-network bypass considered in the meta-mesh design concept of [9]. But it bears explaining how a dual-span SRLG and a nodal bypass differ because at first glance they can seem to be almost identical arrangements that cause one physical failure to escalate into two logical failures.…”

Section: Outlinementioning

confidence: 95%

“…Pre-processing steps to enumerate the sets of eligible restoration routes are discussed in Section 3. A variation on the SCA model for span-restorable network design is joint capacity assignment (JCA), where working routes and capacity are jointly designed optimally with restoration routing and spare capacity [8,9]. This study is, however, based solely on non-joint models for capacity planning in which all demands are first shortest-path routed before solving optimally for the spare capacity assignment.…”

Section: Basic Span-restorable Spare Capacity Design Modelmentioning

confidence: 99%

“…Methods for this include shared backup path protection (SBPP) [4,5], dedicated 1 + 1 APS [6], and dynamic path restoration [7]. Path-oriented schemes (except for 1 + 1) tend to be slightly more efficient in terms of spare capacity requirements [7][8][9] than span restoration schemes. But this comes at a price in design complexity and often speed as well due to the greater geographical extent of the recovery process.…”

Section: Why Span Restoration?mentioning

confidence: 99%

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Shared-Risk Logical Span Groups in Span-Restorable Optical Networks: Analysis and Capacity Planning Model

Doucette¹,

Grover

2005

Photon Netw Commun

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Abstract. In an optical transport network distinct logical groups of lightwave channels between neighboring OXC nodes (called spans) may sometimes be realized over a common physical resource such as a duct or conduit, and hence share a common cause of failure. This is closely related to the concept of shared risk on individual channels or links, called SRLGs, which is relevant to pre-planned path protection schemes with shared capacity on backup paths. But when considering span-restorable networks, shared risk over logical spans (not individual channels) is the corresponding issue of concern. This work considers several aspect of how such shared-risk span groups (SRSG) affect the protection capacity design and other aspects of span-restorable mesh networks. We provide a model for capacity planning any span-restorable network in the presence of a known set of such shared-risk spans and study the relationship between capacity requirements and the number and placement of such situations. This provides guidelines as to how many SRSGs can be sustained before the capacity penalty becomes severe and methods to diagnose which of them are the most limiting to overall protection efficiency. One finding of interest is that if a given percentage of all possible dual-failure combinations incident to a common node are allowed for in the design, then nearly the same percentage of other dual-span failure combinations (any two spans in the network) will also be restorable. We also show that designing a network to withstand even a small number of multi-span co-incident spared-risk span groups will yield a significant improvement in overall dual-failure restorability and hence also in network availability.

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Section: Outlinementioning

confidence: 95%

Section: Basic Span-restorable Spare Capacity Design Modelmentioning

confidence: 99%

Section: Why Span Restoration?mentioning

confidence: 99%

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Shared-Risk Logical Span Groups in Span-Restorable Optical Networks: Analysis and Capacity Planning Model

Doucette¹,

Grover

2005

Photon Netw Commun

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“…In work on sparser topologies we have seen threshold hop limits of up to 12, although this is almost always a result of many degree-two nodes in chain-like subnetworks. (In the meta-mesh abstraction [10] of those networks, the effective threshold hop limit can more often be expected to again be in the five to seven hop range, say.) Advantages to restricting the hop limit as much as possible in survivable design are numerous and obvious and include increased availability (fewer network elements involved in restoration), reduced regenerator cost associated with protection paths, and depending on signalling protocols, possibly increased restoration speed from fewer nodes having to react.…”

Section: Path Length Issues In Survivable Network Designsmentioning

confidence: 99%

“…Equations (7), (8), and (9) ensure that the number of copies of p-cycle p in the solution is the maximum of the number forced by any single span failure. Equations (10) and (11) are "backup" constraints to ensure that, if cycle p is not eligible to restore span i using either the L or R side, then it will not be considered for protection of that span. While not strictly required, (10) and (11) are "added valid knowledge" constraints that provide extra information and may thus hasten the solution process.…”

Section: P-cycle Model With Direct Path Length Constraintsmentioning

confidence: 99%

p-cycle network design with hop limits and circumference limits

Kodian

Sack

Grover

First International Conference on Broadband Networks

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p-Cycles offer an approach to protection of optical transport networks which is as fast as a ring-based network but with mesh-like capacity efficiency. One misconception about p-cycle designs seems to be that they involve long protection paths, even though it is trivial to limit the circumference of cycles admitted to the design problem. In addition, through straddling span considerations the average protection path on a p-cycle is actually shorter than in a corresponding ring. Nonetheless there are some open questions regarding path and cycle circumference limit effects with p-cycles. One question is whether p-cycle networks exhibit a "threshold hop-limit" effect corresponding to that well-known aspect of spanrestorable mesh networks. (Beyond the threshold hop-limit there are negligible savings in capacity.) To study this question we extend the existing p-cycle network design theory to include the capability of direct restriction of protection path lengths, rather than indirect restriction through circumference limits. A second, quite practical question is to ask how well simple limitation of cycle circumferences serves as a surrogate for a more involved design method of directly asserting a hop (or distance) limit on the maximum length of protection paths. The answers to the questions and the methods developed to address them both enhance our ability to design p-cycle networks in which optically transparent length may affect transmission quality, or where the length of protection paths may affect cost if regeneration is required en route of a protection path. The main findings are that p-cycles do exhibit threshold hop-limiting effects (at about two or three hops above those in corresponding mesh networks) and that cycle limiting is a simple and effective surrogate for direct limitation on path lengths in p-cycle design problems.

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Dual‐failure restorability analysis of span‐restorable meta‐mesh networks

2020

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The span‐restorable meta‐mesh model was previously designed as a cutting‐edge technique that enhanced the spare capacity efficiency in low average nodal degree networks. In this technique, lightpaths that fully traverse chains of degree‐2 nodes are provided with a logical express bypass span allowing a distinction between the internal and external working flow capacity that transit the chain. In the event of span failure, lightpaths which would normally traverse the chain in its entirety are allowed to fail back to its anchor nodes such that only the intrachain flow requires allocation of spare capacity. Previous work on the meta‐mesh design considered only single failure restorability. The work herein analyzes dual span failure situations by developing two new integer linear programming models. The first model provides the minimum total cost of designing a meta‐mesh network capable of withstanding dual span failure scenarios. The second model offers a maximization of the dual failure restorability by minimizing the number of nonrestored working capacities with a given limit of total spare capacity investment. Experiments are performed on six master test‐case networks of various topologies and scales.

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Design of a meta-mesh of chain subnetworks: enhancing the attractiveness of mesh-restorable WDM networking on low connectivity graphs

Cited by 33 publications

References 19 publications

Shared-Risk Logical Span Groups in Span-Restorable Optical Networks: Analysis and Capacity Planning Model

Shared-Risk Logical Span Groups in Span-Restorable Optical Networks: Analysis and Capacity Planning Model

p-cycle network design with hop limits and circumference limits

Dual‐failure restorability analysis of span‐restorable meta‐mesh networks

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