SLA-aware differentiated QoS in elastic optical networks

A hybrid load-balancing and energy-aware RWA algorithm for telecommunication networks

Distributed dynamic QoS-aware routing in WDM optical networks

Advances in optical technologies have enabled the deployment of wavelength division-multiplexed (WDM) transmission systems capable of providing huge amounts of bandwidth across long distances. In this scenario, dynamic routing for direct provisioning of optical paths at the WDM layer becomes a challenging problem. Any distributed algorithm for routing dynamic traffic demands on optical transport infrastructures should be simple, flexible, efficient and scalable. The contribution of this paper is a novel integrated routing and grooming scheme for setting-up bandwidth guaranteed paths on hybrid wavelength and label switched networks. Our proposal exploits and refines the minimum interference routing idea according to an improved and re-optimized resource and traffic-aware approach, where critical links are detected and weighted according to a low complexity all-pairs minimum cut strategy that substantially reduce the overall number of calculations and hence the computational cost. The valuable results achieved in the comparison against other well-known reference techniques clearly demonstrate that our algorithm is very time-efficient while performing better in terms of blocking probability.

A Minimum Cut Interference-based Integrated RWA Algorithm for Multi-constrained Optical Transport Networks

In this paper we present the design of an Advanced Centralized RWA Protocol (ACRP) in which the cost of a lightpath is computed based on its number of available free wavelengths and number of wavelength conversions. Centralized Management System (CMS I) assigns optimal primary and backup lightpaths. CMS II updates the optimal primary and backup lightpaths as and when the number of free wavelengths of primary lightpath reaches the threshold value ‘N≤ 4’. In case of failure the data will be rerouted through the backup lightpath and very next lightpath with best cost is assigned as backup lightpath. The advantage of this protocol is that the tasks are shared using two CMS which improves the computation bottleneck and also if one fails the other will take over the entire process. By simulation results, we showed that our proposed protocol has minimal request rejection and set-up time.

Advanced centralized RWA protocol for WDM networks

As the WDM technology matures and the demand for bandwidth increases, dynamic provisioning of lightpaths at the WDM layer becomes an important and challenging problem In this paper, we consider the problem of dynamic routing and wavelength assignment in wavelength-routed optical networks The conventional approach to this problem is to select a route from a set of candidate routes, which has a common wavelength available on all the links of the route In this paper, we propose a distributed algorithm which selects a route based on the state of the network (called preferred link approach) In this approach, a route is selected link by link based on a preference value given to each of the links We propose three different heuristic functions for calculating the preference of the links, depending on the cost and congestion on the links We evaluate our routing algorithm in terms of call acceptance ratio, cost of the path, hop length, and call setup time Our experimental results suggest that our algorithm not only out performs the existing methods with respect to average call acceptance ratio, but, also improves the fairness among different hop connections, which is an important result in the case of WDM optical networks

Preferred Link Based Distributed Adaptive Routing in Wavelength Routed Optical Network

Wide-area cloud provider networks must support the bandwidth requirements of network traffic despite failures. Existing traffic engineering (TE) schemes perform no better than an approach that optimally routes traffic for each failure scenario. We show that this results in sub-optimal routing decisions that hurt performance, and are potentially unfair to some traffic across scenarios. To tackle this, we develop Flexile, which exploits and discovers opportunities to improve network performance by prioritizing certain traffic in each failure state so that it can meet its bandwidth requirements. Flexile seeks to minimize a desired percentile of loss across all traffic flows, while modeling diverse needs of different traffic classes. To achieve this, Flexile consists of (i) an offline phase that identifies which failure states are critical for each flow; and (ii) an online phase, which on failure allocates bandwidth prioritizing critical flows for that failure state, while also judiciously allocating bandwidth to non-critical flows. For tractability, Flexile's offline phase uses a decomposition algorithm aided with problem-specific accelerations. Evaluations using real topologies, and validated with emulation testbed experiments, show that Flexile outperforms state-of-the-art TE schemes including SWAN, SMORE, and Teavar in reducing flow loss at desired percentiles by 46% or more in the median case.

S. Dharma Rao

Papers

Distributed dynamic QoS-aware routing in WDM optical networks

Preferred Link Based Distributed Adaptive Routing in Wavelength Routed Optical Network

Flexile: meeting bandwidth objectives almost always