Link Congestion Aware Proactive Routing for Dynamic Traffic in Elastic Optical Networks

Abstract

Fixed alternate routing is a potential routing scheme for routing and spectrum allocation (RSA) in elastic optical networks (EON) which has less complexity and time consumption compared to adaptive routing scheme. However, adaptive routing scheme efficiently reduces the amount of network bandwidth blocking probabilities (BBPs) which uses traffic engineered paths and tunes according to the current network status. In this paper, an algorithm for routing is proposed for dynamic traffic in EON which works iteratively to arrange the pre-computed fixed alternate routes offline to incorporate link loading. During the offline process, the pre-computed routes are arranged with an objective to reduce link congestion and diverts lightpaths to the under-utilized links. The proposed scheme merges the properties of fixed alternate routing and adaptive routing and is utilized for dynamic traffic in EON. It has been shown through simulation results that the proposed scheme efficiently improves the performance of RSA in EON and reduces the amount of BBPs compared to the fixed alternate routing and an existing constrained-lower-indexed-block (CLIB) based adaptive routing algorithm. The proposed LCA greatly reduces congestion over all links during dynamic network operation and lowers congestion spikes over some links which occues in the existing alternate routing scheme in different network scenarios.

An Iterative Optimization Approach for Routing, Modulation, and Categorical Spatial Bandwidth Block Allocation to Improve Network Performance for Dynamic Traffic in Elastic Optical Networks

“…Routing and spectrum allocation (RSA) is a popular research area in EON to allocate limited resources in an optimal way [12], [13]. In RSA, a lightpath is established between the two transponders through a selected route and allocating contiguous and continuous FS's to support traffic demand.…”

“…Optimization models are formulated with an objective to establish maximum static lightpaths between transponders which are constrained by the network resources. There are few optimization models [12], [13], [27], [28] which are formulated with static traffic and their results are utilized for routing purpose for dynamic traffic. However, the routing information changes in these models with changes in network traffic load (Erlang) as the lightpath establishments are subject to traffic loads (Erlang).…”

“…It is given by a mathematical expression in Eq. ( 11) [12], [30]. The value of average network ABPM ranges from 0 to 1 and shows spatial fragmentation.…”

Hybrid Optimized Approaches for Routing and Resource Reservation Protocols in Optical Networks

“…(5), arg min λ∈{1,2,3,...} represents the argument of minimum value of a wavelength (i.e, the number of channels) for which Erlang B formula satisfies the mean arrival rate to achieve the bound on the blocking probability value B avg . In this work, we have adopted the recursive form of Erlang B formula [10] given in Eq. (6) to avoid numerical overflow.…”

“…Each FS has typically a bandwidth equal to 12.5 GHz [8], [9]. EON supports different modulation schemes, heterogeneous data rates, and heterogeneous FS allocation which will further increase the efficiency of optical networking with an improved bandwidth utilization [10], [11]. However, it further imposes an additional constraint called contiguity.…”