Clustering-based multi-hop protection scheme for long-reach passive optical network against single shared-risk link group failure

The next-generation passive optical networks (NG-PONs) are expected to offer very high data rate to large number of users. Long-reach passive optical network (LR-PON) is considered to be one of the most promising solutions for NG-PONs. Since providing full protection (i.e., 100 % reliability) to each user in LR-PON is complex and cost-prohibitive, we propose in this study a novel heuristic scheme against single shared-risk link group (SRLG) failure to ensure certain degree of reliability (as determined by the network operator) to the users. In the proposed scheme (referred to as clustering-based multi-hop protection or CMHP scheme), we allocate residual capacity of backup optical network units (ONUs) among the ONUs that require protection by using bypass-based multi-hop traffic transmission strategy through backup fibers. CMHP scheme reduces the total length of backup fibers to be deployed between the ONUs (that require protection) and the respective backup ONUs through sharing of the backup fibers. In this study, we evaluate the total required length of backup fiber for a given network setting and different reliability requirements (viz. 75, 85 and 95 %). With the help of exhaustive simulations, we show that CMHP scheme significantly reduces the total length of backup fiber with reference to existing scheme to protect against single SRLG failure. We also explore a heuristic scheme referred to as clustering-based multi-hop protection with consideration of street layout (i.e., CMHP-SL) to implement CMHP scheme in practical scenario with due consideration of the street layout. CMHP-SL scheme provides protection to ONUs following a cost-efficient approach based on the existing fiber infrastructure in the distribution section.