Survivable IP over optical transport networks

Abstract

Survivability strategies for a single network layer have been investigated for many years in the research and development of communication networks. Some of these networks already have available standards for protection methods and techniques (e.g. SONET). However, using only one survivability technique running in a single-layer is not always the optimal solution if we want to achieve a certain level of QoS for all services without increasing the cost of their use. One of the most promising solutions for overcoming this problem is to use multi-layer survivability techniques running in different network layers. The use of multi-layer survivability strategies requires precise definitions of the survivability functionalities that need to be allocated at each layer and the coordination between the network layers. This thesis investigates survivability schemes for optical networks that rely only on a single layer, as well as for those that have more than one layer survivability functions and uses different approaches to solve QoS survivability related problems. We have simulated the restoration process of single transport layer: IP; ATM; SONET and OTN, which have been analyzed by similar studies. Also, we have simulated the process of the multi-layer restoration schemes for previously analyzed IP/SONET, IP/OTN and IP-MPLS/OTN by using the hold-off timer concept. We have extended their restoration concept and applied it for IP/OTN and ATM/SONET restoration schemes. Further more, we have introduced IP Restoration/OTN Protection combined multi-layer survivability, IP Restoration/SONET Protection combined multi-layer survivability and IP-MPLS Protection and Restoration/OTN Protection combined multi-layer survivability. In this thesis, we have combined the analyses with simulations to form a comprehensive study for the IP over OTN survivability across different architectures. The study focuses on four of the most commonly used network architectures of the IP over OTN architecture possibilities: IP/POS/OTN; IP/GbE/OTN; IP-MPLS/OTN, and the traditional, still commonly used IP/ATM/SONET/OTN.