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RMCSA Algorithm for Congestion-Aware and Service Latency Aware Dynamic Service Provisioning in Software-Defined SDM-EONs

Baljinder Singh Heera, Shrinivas Petale, Yatindra Nath Singh, Suresh Subramaniam

TL;DR

This paper tackles the dynamic RMCSA problem in SDM-EONs by integrating congestion awareness and service-latency considerations into routing decisions. It introduces CALA-RMCSA, a congestion- and latency-aware dynamic routing algorithm, along with a CA-AP mechanism, a CA-K^{th} disjoint path extension, and a memoization-based caching strategy to accelerate path finding. The approach yields lower blocking, higher spectrum utilization, and reduced service delay compared with SP-, KSP-, KDP-, and LB-RMCSA across two realistic topologies, demonstrating resilience to single-link failures and eliminating the need for periodic link-weight updates. The combination of real-time congestion metrics, multiple congestion-aware alternative paths, and caching offers practical benefits for capacity- and latency-constrained future networks.

Abstract

The implementation of 5G and the future deployment of 6G necessitate the utilization of optical networks that possess substantial capacity and exhibit minimal latency. The dynamic arrival and departure of connection requests in optical networks result in particular central links experiencing more traffic and congestion than non-central links. The occurrence of congested links leads to service blocking despite the availability of resources within the network, restricting the efficient utilization of network resources. The available algorithms in the literature that aim to balance load among network links offer a trade-off between blocking performance and algorithmic complexity, thus increasing service provisioning time. This work proposes a dynamic routing-based congestion-aware routing, modulation, core, and spectrum assignment (RMCSA) algorithm for space division multiplexing elastic optical networks (SDM-EONs). The algorithm finds alternative candidate paths based on real-time link occupancy metrics to minimize blocking due to link congestion under dynamic traffic scenarios. As a result, the algorithm reduces the formation of congestion hotspots in the network owing to link-betweenness centrality. We have performed extensive simulations using two realistic network topologies to compare the performance of the proposed algorithm with relevant RMCSA algorithms available in the literature. The simulation results verify the superior performance of our proposed algorithm compared to the benchmark Yen's K-shortest paths and K-Disjoint shortest paths RMCSA algorithms in connection blocking ratio and spectrum utilization efficiency. To expedite the route-finding process, we present a novel caching strategy that allows the proposed algorithm to demonstrate a much-reduced service delay time compared to the recently developed adaptive link weight-based load-balancing RMCSA algorithm.

RMCSA Algorithm for Congestion-Aware and Service Latency Aware Dynamic Service Provisioning in Software-Defined SDM-EONs

TL;DR

This paper tackles the dynamic RMCSA problem in SDM-EONs by integrating congestion awareness and service-latency considerations into routing decisions. It introduces CALA-RMCSA, a congestion- and latency-aware dynamic routing algorithm, along with a CA-AP mechanism, a CA-K^{th} disjoint path extension, and a memoization-based caching strategy to accelerate path finding. The approach yields lower blocking, higher spectrum utilization, and reduced service delay compared with SP-, KSP-, KDP-, and LB-RMCSA across two realistic topologies, demonstrating resilience to single-link failures and eliminating the need for periodic link-weight updates. The combination of real-time congestion metrics, multiple congestion-aware alternative paths, and caching offers practical benefits for capacity- and latency-constrained future networks.

Abstract

The implementation of 5G and the future deployment of 6G necessitate the utilization of optical networks that possess substantial capacity and exhibit minimal latency. The dynamic arrival and departure of connection requests in optical networks result in particular central links experiencing more traffic and congestion than non-central links. The occurrence of congested links leads to service blocking despite the availability of resources within the network, restricting the efficient utilization of network resources. The available algorithms in the literature that aim to balance load among network links offer a trade-off between blocking performance and algorithmic complexity, thus increasing service provisioning time. This work proposes a dynamic routing-based congestion-aware routing, modulation, core, and spectrum assignment (RMCSA) algorithm for space division multiplexing elastic optical networks (SDM-EONs). The algorithm finds alternative candidate paths based on real-time link occupancy metrics to minimize blocking due to link congestion under dynamic traffic scenarios. As a result, the algorithm reduces the formation of congestion hotspots in the network owing to link-betweenness centrality. We have performed extensive simulations using two realistic network topologies to compare the performance of the proposed algorithm with relevant RMCSA algorithms available in the literature. The simulation results verify the superior performance of our proposed algorithm compared to the benchmark Yen's K-shortest paths and K-Disjoint shortest paths RMCSA algorithms in connection blocking ratio and spectrum utilization efficiency. To expedite the route-finding process, we present a novel caching strategy that allows the proposed algorithm to demonstrate a much-reduced service delay time compared to the recently developed adaptive link weight-based load-balancing RMCSA algorithm.

Paper Structure

This paper contains 16 sections, 8 equations, 9 figures, 3 tables, 3 algorithms.

Table of Contents

  1. Introduction
  2. System Model
  3. Physical Layer Model
  4. Request Model and RMCSA Problem
  5. Link-betweenness Centrality
  6. Relevant Works and Paper Contributions
  7. Proposed Algorithms
  8. Congestion-Aware Alternative Paths
  9. Congestion-Aware $K^{th}$ Disjoint Path
  10. Novel Caching Method to Speed-up the Route Finding Process
  11. Congestion-Aware and latency Aware Resilient CALA-RMCSA Algorithm
  12. Simulation Experiments and Results Discussion
  13. Simulation Environment
  14. Performance Metrics
  15. Results and Discussion
  16. ...and 1 more sections

Figures (9)

  • Figure 1: Link betweenness centrality of USNET networks' links.
  • Figure 2: Illustrative example of route finding of KSP, KDP and CA-AP algorithms.
  • Figure 3: Flowchart of the steps involved in implementing cache.
  • Figure 4: Network topologies with link length in km: (a) Europe Network, and (b) German Network
  • Figure 5: Request blocking probability of (a) Europe network, and (b) German network.
  • ...and 4 more figures