Impact of fragmentation in quantum signal channel of quantum key distribution enabled optical networks

Abstract In QKD‐enabled optical networks (QKD‐enabled ONs), fragmentation is one of the serious issues which can be mitigated through appropriate management of network resources. Thus, efficient allocation of network resources during routing and resource assignment is important to minimise the impact of time slot fragmentation in the quantum signal channel (QSCh) of QKD‐enabled ONs. The authors address the fragmentation problem in the QSCh and propose a new fragmentation‐suppressed routing and resource assignment (FS‐RRA) approach. To evaluate the performance and to analyse the effect of time slot fragmentation in QSCh of QKD‐enabled ONs, the proposed FS‐RRA approach is compared with two existing resource assignment approaches, namely, the first‐fit (FF) and random‐fit (RF) for two different networks. Simulation results show that the proposed approach reduces fragmentation by 2.97% and 6.69% for NSFNET and 1.77% and 5.91% for UBN24 in terms of external fragmentation compared to FF and RF, respectively. Furthermore, the proposed approach reduces blocking by 4.03% and 14.28% for NSFNET and 2.61% and 13.44% for UBN24 and improves resource utilisation up to 3.44% and 5.96% for NSFNET and 3.08% and 7.64% for UBN24 compared to FF and RF, respectively.