Sparing strategies for tunable line cards in optical networks

In this paper, we study the problem of tunable line card sparing in optical networks. Specifically, we consider three strategies; an on-site sparing strategy whereby spare units are located at the traffic generating sites, a central sparing strategy in which spares are located at a central warehouse, and finally a hybrid strategy that places spares both on-site and in a central warehouse in a optimized manner. We analyze and compare the three strategies in terms of the number of spares required to meet a target availability metric, and show that the hybrid strategy is the most efficient.