Moving Towards Upgradeable All-Optical Networks through Impairment-aware RWA Algorithms

For the mixed-line-rate (MLR) wavelengthdivision multiplexing (WDM) networks, each wavelength in a fiber can provide different transmitting rates (in 10/40/100 Gbps) by using different modulation formats. Since the MLR-WDM becomes a cost-efficient technique for the network upgrading, the problem of supporting virtual topology reconfiguration (VTR) becomes an important issue. In this paper, the VTR problem is studied for MLR-WDM networks under dynamic traffic demand. By monitoring traffic of the lightpaths, a reconfiguration method is proposed to follow the changes in traffic without a priori knowledge of the future traffic pattern. The proposed algorithm can optimize resource utilization and network traffic performance by either adjusting (increasing or decreasing), adding or deleting one or more lightpaths at a time. Simulations reveal the effects of the various system parameters. Specifically, we find that the proposed method adapts very well to the changes in the offered traffic on MLR-WDM networks.

Section: Vtd On Mlr-wdm Networkmentioning

confidence: 99%

Section: Vtd On Mlr-wdm Networkmentioning

confidence: 99%

Section: Offered Loadsmentioning

confidence: 99%

See 1 more Smart Citation

Virtual topology reconfiguration for mixed-line-rate optical WDM networks under dynamic traffic

Din

2015

“…In terms of physical impairment in WDM networks, recent studies were mainly focusing on physical impairment-aware routing and wavelength assignment (RWA) for connection requests [2,4,[11][12][13][14]. The problem of impairment-aware dedicated path protection [9] and multiple paths provisioning [15] have been studied and corresponding heuristic algorithms have been evaluated.…”

Section: Related Work and Challengesmentioning

confidence: 99%

Performance enhancement for impairment-aware SRLG failure protection in wavelength-routed optical networks

Cheng

Yeo

et al. 2010

With the increase of size and number of shared risk link groups (SRLGs) in WDM networks, path protection tends to have longer working paths and backup paths due to SRLG-disjoint constraints, which makes physical impairment a major concern in working path and backup path provisioning, particularly in large-sized all optical networks. As a simple and efficient algorithm, the working path first algorithm is often used for path protection against SRLG failures, where the working path is calculated first by using the shortest-path algorithm on the graph, followed by using the SRLG-disjoint shortest path as backup path. Compared with the working path, the backup path calculated after the working path in the working path first algorithm is more vulnerable to physical impairment, since it may be much longer than the working path. As a result, if we reject those connections that cannot meet the physical impairment requirement, with SRLGs the blocking probability of path protection will be much higher. We argue that impairment must be taken into account together with capacity efficiency in a comprehensive way during SRLG-disjoint working path and backup path selection. To solve this problem, we motivate the needs to study physical impairment-aware sharedpath protection by considering two policies. Policy I uses two SRLG-disjoint least impairment paths as working path and backup path, respectively, and Policy II tries to benefit from both the shortest path and the least impairment path by choosing them intelligently. Analytical and simulation results show: (1) compared with impairment-unawareness, impairment-aware SRLG failure protection performs much better in terms of blocking probability especially with strong physical impairment constraints; (2) impairment-aware SRLG failure protection can significantly reduce physical-layer blocking probability; and (3) the algorithm based on Policy II achieves a good balance between capacity efficiency and physical impairment requirement.

“…In general, mixed line rate problems have scarcely been explored in optical communications. In [10], a RWA algorithm called DIRWA (Dispersion-optimized Impairment-aware RWA) is proposed. DIRWA incorporates CD information to minimize the lightpath blocking rate in a multirate line dynamic case where the lightpath requests arrive randomly.…”

mentioning

confidence: 99%

Mixed line rate virtual topology design considering nonlinear interferences between amplitude and phase modulated channels

Aparicio-Pardo

Pavón‐Mariño

Zsigmond³

2011

In the last years, the migration from 10 to 40/100 Gbps networks has been proposed as a solution to increase the capacity of transparent optical networks. Initially, the replacement of 10 Gbps legacy equipment was considered. Nowadays, some works point out that the deployment of mixed line rate (MLR) networks, where 10 Gbps and higher bit rate Gbps channels share the same fiber, could be more cost effective than the total replacement of 10 Gbps systems. In this paper, we investigate the planning of 10/40 Gbps MLR networks using the ITU 50 GHz grid, considering nonlinear interferences between 10 and 40 Gbps channels, which degrade the quality of transmission. This approach is novel in the literature. In addition, we conduct a set of tests normalizing the length of fiber links, to observe the trends in MLR planning for different network sizes.