Space Laser Communication Assisted Protection Scheme Against SRLG Failures in Terrestrial Optical Networks

Survivability has already been an important research focus for the terrestrial optical network (TON). Various survivability technologies such as the pre-configured structure scheme, the multi-path protection scheme, the link/path-based restoration scheme, the disaster-aware network deployment scheme, and the degraded service tolerant provisioning scheme, have been developed to achieve the uninterrupted traffic transmission. However, most of the survivability technologies strongly rely on the network connectivity of the TON, and thus it is difficult to deal with shared risk link group (SRLG) failures caused by natural disasters or man-made destructions. Recently, the space laser communication (SLC) is widely studied and obtains rapid development. It can provide homogeneous spatial light-paths between two satellites or between a satellite and an optical ground station (OGS). The SLC brings a new solution to improve the survivability of the TON. In this paper, we study the SLC assisted survivability technologies against SRLG failures caused by natural disasters occurring on the ground. The SLC assisted dedicated protection (SLC-DP) scheme and the SLC assisted shared protection (SLC-SP) scheme are proposed. Heuristic algorithms are developed to realize those two schemes. Numerical results show that the SLC-SP scheme has a low blocking probability and the capacity of satellite-to-earth laser links plays a more important role than that of inter-satellite laser links.