Survivable Grooming Research Articles

Energy-Efficient Survivable Grooming in Software-Defined Elastic Optical Networks

Survivability in the OpenFlow-based software-defined elastic optical networks (SD-EONs) are more challenging than that in the conventional optical networks because failures can affect control plane operations. Meanwhile, traffic grooming is enabled by sliceable transponders can reduce power consumption and obtain higher spectrum efficiency. In this paper, we study the survivable grooming routing and spectrum allocation in SD-EON. First, provide an integer linear programming formulation to minimize both the required transponders and the maximum number of occupied frequency slots. Then, we develop a heuristic algorithm called shared backup path grooming protection (SBPGP) to get enough protection and less resources consumption. Extensive simulations are performed to study the power consumption of optical elements in data plane. Numerical results show that the proposed SBPGP scheme achieves better performances than the traditional shared backup path protection without grooming.

Cost Efficient Grooming Based on p-Cycle Protection in Elastic Optical Networks

The pre-configured protection cycle, known as p-cycle, is an efficient method, which may overcome long restoration time and complicated protection switching procedure comparing with other schemes. Meanwhile, traffic grooming enabled by sliceable transponders can reduce power consumption and obtain higher spectrum efficiency. In this paper, we study survivable grooming problem based on p-cycle protection in Elastic Optical Networks (EONs). We develop a heuristic algorithm called Shared p-Cycle Grooming Protection (SCGP) to get enough protection and less resources consumption. Numerical simulation results show that the proposed SCGP scheme achieves better performances than the traditional p-Cycle Protection (CP) schemes without grooming.

Survivable waveband grooming in multi-domain optical networks

Since the size of traffic demands ranges from sub-wavelength-level to wavelength-level, traffic demands need to be aggregated and carried over the network in a cost effective manner to make sure that the resources can be utilized effectively. Therefore, the technique called waveband grooming is proposed to save the cost and to reduce the number of switching ports in Optical-Cross Connects (OXCs). However, the existing waveband grooming algorithms are mostly limited to single-domain optical networks and also do not consider the survivability. The current optical backbones keeps enlarging, and the backbones are actually divided into multiple independent domains to provide the needed scalability and the confidentiality. It is necessary to study the survivable waveband grooming in multi-domain optical networks. In this paper, we propose two new heuristic algorithms called Intra-domain Sub-path Survivable Grooming (ISSG) algorithm and Inter-domain End-to-end Survivable Grooming (IESG) algorithm, respectively. In ISSG, we allocate an end-to-end inter-domain working path for each demand and then calculate a link-disjoint backup sub-path for each intra-domain working sub-path. In IESG, we allocate two link-disjoint end-to-end inter-domain paths for each demand, one is working path and the other one is backup path. Simulation results show that ISSG and IESG have similar trend with different parameters. In addition, IESG has lower blocking probability while ISSG has lower average port-cost.

Survivable power efficiency oriented integrated grooming in green networks

The wide interests in the power savings of IP over wavelength-division-multiplexing (WDM) optical networks have recently risen in both academic and industrial communities. In an effort to tackle this problem, the hybrid grooming (traffic grooming along with an optical bypass) approach has been presented to reduce the power consumed by the entire network infrastructure, including the transmission ports of routers and optical-electrical-optical (OEO) conversions. However, the related works pay little or no attention to the power consumed to ensure the resiliency of the overall network. Meanwhile, the power consumed by components used for establishing lightpaths is not simultaneously taken into account. One survivable network with the higher power efficiency thereby save more power with hybrid grooming, require the lower power consumption of establishing lightpaths and exhibit the shorter recovery time. For the first time, this paper proposes the evaluating models of both survivable power ratio and protection switching time. We subsequently compare two green and survivable grooming heuristics, known as Single-hop Survivable Grooming with considering Power Efficiency (SSGPE) and Multi-hop Survivable Grooming with considering Power Efficiency (MSGPE). Simulation results demonstrate that, MSGPE obtains the higher power efficiency and resiliency although it has the slightly higher time complexity in comparison to SSGPE. Furthermore, it is effective to exploiting waveband merging in our MSGPE to form integrated grooming for further port savings.

Resilient traffic grooming for WDM networks

Traffic grooming techniques are used to combine low-speed individual requests for connections onto high-speed lightpaths in an efficient manner. Design of survivable grooming capable networks is of critical importance. For such networks, protection may take place at the lightpath level or at the connection level. However, optimal formulations for implementing protection at either level are computationally intractable and can only be used for very small networks. We present an efficient integer linear program (ILP) formulation for the complete survivable traffic grooming problem, including topology design, traffic routing, and routing and wavelength assignment, using both dedicated and shared protection at the lightpath level. Unlike existing formulations, our ILP is able to generate optimal solutions for practical sized networks with hundreds of traffic requests.

Multiple link failures survivability of optical networks with traffic grooming capability

This paper investigates the problem of survivable traffic grooming (STG) in shared mesh optical networks and proposes different frameworks for improving the survivability of low speed demands against multiple near simultaneous failures. Spare capacity reprovisioning has recently been considered for improving the overall network restorability in the event of dual failures; here, after the recovery form the first failure, some connections in the network may become unprotected and exposed to new failures. Capacity reprovisioning then allocates protection resources to unprotected and vulnerable connections so that the network can withstand a future failure. In this paper, we propose two different reprovisioning schemes (lightpath level reprovisioning, LLR, and connection level reprovisioning, CLR); they differ in the granularity at which protection resources are reprovisioned. Further, each of these schemes is suitable for a different survivable grooming policy. While LLR provides collective reprovisioning of connections at the lightpath level, CLR reprovisions spare bandwidth for lower speed connections instead. We use simulation methods to study the performance of these schemes under two grooming policies (PAL and PAC), and we show that while CLR reprovisions substantially many more connections than LLR (i.e., potentially more management overhead) CLR yields a much better network robustness to simultaneous failures due to its superior flexibility in using network resources.

A cost effective approach for survivable multicast traffic grooming in bidirectional multiwavelength ring networks

In this paper, we address the problem of survivable multicast traffic grooming in WDM bidirectional ring networks. The rapid growth of multicast applications such as video conferencing, distance learning, and online auction, has initiated the need for cost-effective solutions to realize multicasting in WDM optical networks. Many of these applications, being time critical and delay sensitive, demand robust and fault-tolerant means of data communication. The end user traffic demands in metro environment are in fractional bandwidth as compared to the wavelength channel capacity. Providing survivability at connection level is resource intensive. Hence cost-effective solutions that require minimum resources for realizing survivable multicasting are in great demand. In order to realize multicast traffic grooming in bidirectional ring networks, we propose a node architecture based on Bidirectional Add Drop Multiplexers (BADM) to support bidirectional add/drop functionality along with traffic duplication at each node. We also propose two traffic grooming algorithms, namely Survivable Grooming with Maximum Overlap of Sessions (SGMOS) and Survivable Grooming with Rerouting of Sessions (SGRS). Extensive simulation studies reveal that the proposed algorithms consume minimum resources measured in terms of BADM grooming ports, backup cost, and wavelengths.

Survivable traffic grooming with path protection at the connection level in WDM mesh networks

Survivable traffic grooming (STG) is a promising approach to provide reliable and resource-efficient multigranularity connection services in wavelength-division-multiplexing (WDM) optical networks. In this paper, we study the STG problem in WDM mesh optical networks employing path protection at the connection level. Both dedicated-protection and shared-protection schemes are considered. Given network resources, the objective of the STG problem is to maximize network throughput. To enable survivability under various kinds of single failures, such as fiber cut and duct cut, we consider the general shared-risk-link-group (SRLG) diverse routing constraints. We first resort to the integer-linear-programming (ILP) approach to obtain optimal solutions. To address its high computational complexity, we then propose three efficient heuristics, namely separated survivable grooming algorithm (SSGA), integrated survivable grooming algorithm (ISGA), and tabu-search survivable grooming algorithm (TSGA). While SSGA and ISGA correspond to an overlay network model and a peer network model, respectively, TSGA further improves the grooming results from SSGA and ISGA by incorporating the effective tabu-search (TS) method. Numerical results show that the heuristics achieve comparable solutions to the ILP approach, which uses significantly longer running times than the heuristics.