Efficient Routing Protection Algorithm Based on Optimized Network Topology

Network failures are unavoidable and occur frequently. When the network fails, intra-domain routing protocols deploying on the Internet need to undergo a long convergence process. During this period, a large number of messages are discarded, which results in a decline in the user experience and severely affects the quality of service of Internet Service Providers (ISP). Therefore, improving the availability of intra-domain routing is a trending research question to be solved. Industry usually employs routing protection algorithms to improve intra-domain routing availability. However, existing routing protection schemes compute as many backup paths as possible to reduce message loss due to network failures, which increases the cost of the network and impedes the methods deployed in practice. To address the issues, this study proposes an efficient routing protection algorithm based on optimized network topology (ERPBONT). ERPBONT adopts the optimized network topology to calculate a backup path with the minimum path coincidence degree with the shortest path for all source purposes. Firstly, the backup path with the minimum path coincidence with the shortest path is described as an integer programming problem. Then the simulated annealing algorithm ERPBONT is used to find the optimal solution. Finally, the algorithm is tested on the simulated topology and the real topology. The experimental results show that ERPBONT effectively reduces the path coincidence between the shortest path and the backup path, and significantly improves the routing availability

Inter-domain router placement and traffic engineering

The Internet is organized as an interconnection of separate administrative domains called Autonomous Systems (AS). The Border Gateway Protocol (BGP) is the de facto standard for controlling the routing of traffic across different ASs. It supports scalable distribution of reachability and routing policy information among different ASs. In this paper, we study a network design problem which determines (1) the optimal placement of border router(s) within a domain and (2) the corresponding inter-and intra-domain traffic patterns within an AS. Practical constraints imposed by BGP and other standard shortest-path-based intra-domain routing protocols are considered. The problem is formulated as a variant of the uncapacitated network design problem (UNDP). While it is feasible to use a brute-force, integer-programming-based approach for tackling small instances of this problem, we have resorted to a dual-ascent approximation approach for mid/large-scale instances. The quality of the approximation approach is evaluated in terms of its computational efficiency and network cost sub-optimality. Sensitivity analysis w.r.t. various network/traffic parameters are also conducted. We then describe how one can apply our optimization results to better configure BGP as well as other intra-domain routing protocols. This serves as a first-step towards the auto-configuration of Internet routing protocols, BGP in particular, which is "well-known" for its tedious and error-prone configuration needs.published_or_final_versio

Symmetrical Routes and Reverse Path Congestion Control

We describe new mechanisms to deal with asymmetries that arise in routing protocols. We show how to avoid route asymmetries (due to non-unique shortest paths) by adding random integer link costs. We show in detail how RIP can be modified to avoid route asymmetry with high probability, without affecting either its efficiency or performance metrics such as convergence time. Symmetrical intra-domain routing also makes possible a new form of congestion control that we call Reverse Path Congestion Control (RPCC). We show, using simulations, that RPCC can augment existing TCP congestion control mechanisms to improve start up behavior and to avoid losses at the boundary between domains and the backbone

Hierarchical QoS routing in next generation optical networks

In this paper, we study the problem of inter-domain routing with two additive QoS constraints in hierarchical optical networks. We develop an inter-domain routing protocol that (1) identifies the QoS supported by the paths, (2) selects an inter-domain path that satisfies the QoS requirement of a connection request, and (3) reserves the wavelength on each link along the path in such a way that the number of wavelength converters needed is minimized. Both formal analyses and extensive simulation experiments show that our inter-domain routing protocol outperforms the existing protocols. © 2006 IEEE.published_or_final_versio