Dynamic Wavelength Allocation in IP/WDM Metro Access Networks

Abstract

Increasing demand for bandwidth and proliferation of packet based traffic have been causing architectural changes in the communications infrastructure. In this evolution, metro networks face both the capacity and dynamic adaptability constraints. The increase in the access and backbone speeds result in high bandwidth requirements, whereas the popularity of wireless access and limited number of customers in metro area necessitates traffic adaptability. Traditional architecture which has been optimized for carrying circuit-switched connections, is far from meeting these requirements. Recently, several architectures have been proposed for future metro access networks. Nearly all of these solutions support dynamic allocation of bandwidth to follow fluctuations in the traffic demand. However, reconfiguration policies that can be used in this process have not been fully explored yet. In this thesis, dynamic wavelength allocation (DWA) policies for IP/WDM metro access networks with reconfiguration delays are considered. Reconfiguration actions incur a cost since a portion of the capacity becomes idle in the reconfiguration period due to the signalling latencies and tuning times of optical transceivers. Exact formulation of the DWA problem is developed as a Markov Decision Process (MDP) and a new cost function is proposed to attain both throughput efficiency and fairness. For larger problems, a heuristic approach based on first passage probabilities is developed. The performance of the method is evaluated under both stationary and non-stationary traffic conditions. The effects of relevant network and traffic parameters, such as delay and flow size are also discussed. Finally, performance bounds for the DWA methods are derived.

Performance Evaluation of a Communication Network with Dynamic Bandwidth Allocation and Bulk Arrivals

“…As the batch size distribution parameter (b) varies from 10x10 4 packets/sec to 30x10 4 packets/sec, the first buffer, second buffer and the network average content increase from 36813.2 packets to 85897.4 packets, 18069.5 packets to 42162.1 packets and 54882.6 packets to 128059.4 packets respectively when other parameters remain fixed. As the arrival rate of messages (λ) varies from 1x10 4 messages/sec to 3x10 4 messages/sec, the first buffer, second buffer and the network average content increase from 36813.2 packets to 110439.5 packets, 18069.5 packets to 54208.4 packets and 54882.6 packets to 164647.9 packets respectively when other parameters remain fixed at (1,5,25,4,8) for (t, a, b, μ 1, μ 2 ). Similarly when the values of t, λ, a, and b increases, the utilization of node 1 and node 2 were also increasing.…”

Proposal for an SDN-Like Innovative Metro-Access Optical Network Architecture

“…First of all, it would allow the availability of remote management functions in the end-to-end provisioning of ultra-broadband services and the consequent optimization in the exploitation of network resources, with particular reference to the dynamic bandwidth allocation. In fact, one of the most challenging demands for the future edge networks will be the efficiency in the bandwidth usage in order to increase the network traffic adaptability for hugely variable traffic pattern (e.g., the daily variation of the traffic among the various areas in an urban 2 International Journal of Optics center) [9]. In fact, metro-access traffic is expected to be more strongly time-varying than backbone traffic, since the users are fewer and the averaging effect will be less impactful.…”

Highly efficient optical aggregation network with network functions virtualization

“…Emerging network applications, such as Internet of things and vehicle‐to‐vehicle communication, are imposing unpredictable traffic variations on metro aggregation networks that connect datacenters with AGNs. Thus, metro aggregation networks must effectively transport large‐volume traffic and adapt to such unpredictable traffic . In a metro aggregation network, low‐speed legacy time division multiplexing (TDM) interface technologies, such as synchronous optical networking/synchronous digital hierarchy (SONET/SDH), were used to aggregate voice traffic .…”