Network Protection

Here I recommend some good books on survivable networks, which can be found on Amazon

Survivable Networks: Algorithms for Diverse Routing provides algorithms for diverse routing to enhance the survivability of a network. It considers the common mesh-type network and describes in detail the construction of physically disjoint paths algorithms for diverse routing. The algorithms are developed in a systematic manner, starting with shortest path algorithms appropriate for disjoint paths construction. Key features of the algorithms are optimality and simplicity. Although the algorithms have been developed for survivability of communication networks, they are in a generic form, and thus applicable in other scientific and technical disciplines to problems that can be modeled as a network.
A notable highlight of this book is the consideration of real-life telecommunication networks in detail. Such networks are described not only by nodes and links, but also by the actual physical elements, called span nodes and spans. The sharing of spans (the actual physical links) by the network (logical) links complicates the network, requiring new algorithms. This book is the first one to provide algorithms for such networks.

Mesh-based survivability offers many advantages, but the research, educational and perational communications communities need to absorb new concepts and ideas about network operation; letting the network self-organize its own logical configuration for example. Operators also need to understand, evaluate and adopt new methods and models for network design and planning. This book is designed to contribute to enabling this evolution towards mesh-based survivable networking.

The advent of fiber optic transmission systems and wavelength division multiplexing has led to a dramatic increase in the usable bandwidth of single fiber systems. This book provides detailed coverage of survivability (dealing with the risk of losing large volumes of traffic data due to a failure of a node or a single fiber span) and traffic grooming (managing the increased complexity of smaller user requests over high capacity data pipes), both of which are key issues in modern optical networks.

Network reliability and availability are often confused for many people. As an accurate definition, network reliability means how reliable a network is, which can be represented as a probability that the first failure occurs at a certain moment. In general, with time going on, the probability that the first failure occurs becomes higher and the reliability becomes lower, which means that a network tends to occur a failure.

In contrast, network availability is the possibility that a user can get its service or a network has no failure when the user wants to use the service. Different from network reliability, network availability considers network repair; that is, if a network fails, we can repair it and then use it; though the repair takes some time, after the network is repaired, it goes normal to provide services. For the time interval of network failure, there is a term called mean time to failure (MTTF), and for the time required for network failure repair, there is a termed called mean time to repair (MTTR). Based on these two terms, network availability is defined as MTTF/(MTTF+MTTR), which tells how much percent that a network is up for any moment that a user wants to access the network.