Internet traffic has surpassed voice traffic and is dominating in transmission networks. The Internet Protocol (IP) is now being used to encapsulate various kinds of services. The new services have different requirements than the initial type of traffic that was carried by the Internet network and IP. Interactive services such as voice and video require paths than can guarantee some bandwidth level, minimum delay and jitter. In addition service providers need to be able to improve the performance of their networks by having an ability to steer the traffic along the less congested links or paths, thus balancing the load in a uniform way as a mechanism to provide differentiated service quality. This needs to be provided not only within their domains but also along paths that might traverse more than one domain. For this to be possible changes have been proposed and some are being applied to provide quality of service (QoS) and traffic engineering (TE) within and between domains. Because data networks now carry critical data and there are new technologies that enable providers to carry huge amount of traffic, it is important to have mechanisms to safeguard against failures that can render the network unavailable. In this thesis we propose and develop mechanisms to enable interdomain traffic engineering as well as to speed up the restoration time in optical transport networks. We propose a mechanism, called abstracted path information, that enable peering entities to exchange just enough information to engage in QoS and TE operations without divulging all the information about the internal design of the network. We also extend BGP to carry the abstracted information. Our simulations show that BGP could still deliver the same performance with the abstracted information. In this thesis we also develop a method of classifying failures of links or paths. To improve the restoration time we propose that common failures be classified and assigned error type numbers and we develop a mechanism for interlayer communication and faster processing of signalling messages that are used to carry notification signals. Additionally we develop a mechanism of exchanging the failure information between layers through the use of service primitives; that way we can speed up the restoration process. Finally we simulate the developed mechanism for a 24 node Pan American optical transport network. / <p>QC 20100913</p>