We first show by measurements that BGP peering links fail as frequently as intradomain links and usually for short periods of time. We propose a new fast-reroute technique where routers are prepared to react quickly to interdomain link failures. For each of its interdomain links, each router precomputes a protection tunnel, i.e. an IP tunnel to an alternate nexthop which can reach the same destinations as via the protected link. We propose a BGPbased auto-discovery technique that allows each router to learn the candidate protection tunnels for its links. Each router selects the best protection tunnels for its links and when it detects an interdomain link failure, it immediately encapsulates the packets to send them through the protection tunnel. Our solution is applicable for the links between large transit ISPs and also for the links between multi-homed stub networks and their providers. Furthermore, we show that transient forwarding loops (and thus the corresponding packet losses) can be avoided during the routing convergence that follows the deactivation of a protection tunnel in BGP/MPLSVPNs and in IP networks using encapsulation.

Abstract—This paper surveys several research challenges in interdomain routing. We introduce and describe these challenges in a comprehensible manner, along with a review of the most compelling contributions and ongoing research efforts addressing each of the exposed issues. During this analysis we identify the relation between these research challenges and how they influence each other. We also present our perspectives on why these issues remain largely unsolved, and point out why some of the proposals made so far have not yet been adopted. We hope this could provide some insight on the future directions in this complex research area. Keywords-component; Interdomain Routing, BGP. I.

Abstract-Internetworks that are global in scale, contain multiple administrative domains, and support a range of services present special requirements for routing. Multiple administrative domains introduce the need for policy-sensitive routing. Service heterogeneity intensifies the requirement for type of service (TOS) routing, as well as other protocol support for handling a range of services, from datagrams to multimedia streams. This paper summarizes the key concepts and protocols developed as part of the Interdomain Policy Routing (IDPR) architecture. We place particular emphasis on the route installation and packet forwarding mechanisms because they are critical to protocol performance and differ significantly from current practice in datagram wide area networks. I.