IP restoration vs. optical protection: Which one has the least bandwidth requirements?

Survivability in IP-over-WDM networks has already been extensively discussed in a series of studies. While many studies assume an IP restoration scheme and focus on network connectivity in order to ensure proper recovery, few studies deal with optical protection. We investigate this question with the objective of estimating the respective bandwidth requirements of both recovery schemes, subject to single or multiple failures. We also design a mixed recovery scenario where the recovery is taken care at a different layer depending on the type of failures.Results shows that optical protection is by far the most economical recovery scheme in terms of bandwidth requirements.