The Internet consists of thousands of independent domains with different, and sometimes competing, business interests. However, the current interdomain routing protocol (BGP) limits each router to using a single route for each destination prefix, which may not satisfy the diverse requirements of end users. Recent proposals for source routing offer an alternative where end hosts or edge routers select the end-to-end paths. However, source routing leaves transit domains with very little control and introduces difficult scalability and security challenges. In this paper, we present a multi-path interdomain routing protocol called MIRO that offers substantial flexibility, while giving transit domains control over the flow of traffic through their infrastructure and avoiding state explosion in disseminating reachability information. In MIRO, routers learn default routes through the existing BGP protocol, and arbitrary pairs of domains can negotiate the use of additional paths (bound to tunnels in the data plane) tailored to their special needs. MIRO retains the simplicity of BGP for most traffic, and remains backwards compatible with BGP to allow for incremental deployability. Experiments with Internet topology and routing data illustrate that MIRO offers tremendous flexibility for path selection with reasonable overhead.

The Border Gateway Protocol (BGP) is the standard interdomain routing protocol in the Internet. Inside an Autonomous System (AS), the interdomain routes are often distributed by using BGP Route Reflectors (RR). Today, most RR are simple BGP routers. We show that by adding intelligence to the RR, it is possible to improve both the routing and the packet forwarding in ASes. We show how a versatile RR can help an AS to engineer the flow of its incoming or outgoing interdomain tra#c. We also discuss how a versatile RR could help to reduce the BGP convergence time or reduce the size of the routing tables when providing BGP/MPLS VPN services. 1

Today, most multi-connected autonomous systems (AS) need to control the flow of their interdomain traffic for both performance and economical reasons. This is usually done by manually tweaking the BGP configurations of the routers on an error-prone trial-and-error basis. In this paper, we demonstrate that designing systematic BGP-based traffic engineering techniques for stub ASes are possible. Our approach to solve this traffic engineering problem is to allow the network operator to define objective functions on the interdomain traffic. Those objective functions are used by an optimization box placed inside the AS that controls the interdomain traffic by tuning the iBGP messages distributed inside the AS. We show that the utilization of an efficient evolutionary algorithm allows to both optimize the objective function and limit the number of iBGP messages. By keeping a lifetime on the tweaked routes, we also show that providing stability to the interdomain path followed by the traffic is possible. We evaluate the performance of solution based on traffic traces from two stub ASes of different sizes. Our simulations show that the interdomain traffic can be efficiently engineered by using not more than a few iBGP advertisements per minute. Our contribution in this paper...

Abstract—Giving ISPs more fine-grain control over interdomain routing policies would help them better manage their networks and offer value-added services to their customers. Unfortunately, the current BGP route-selection process imposes inherent restrictions on the policies an ISP can configure, making many useful policies infeasible. In this paper, we present Morpheus, a routing control platform that is designed for configurability. Morpheus enables a single ISP to realize a much broader range of routing policies without requiring changes to the underlying routers or collaboration with other domains. Morpheus allows network operators to: (1) make flexible trade-offs between policy objectives through a weighted-sum based decision process, (2) realize customer-specific policies by supporting multiple routeselection processes in parallel, and allowing customers to influence the decision processes, and (3) configure the decision processes through a simple and intuitive configuration interface based on the Analytic Hierarchy Process, a decision-theoretic technique for balancing conflicting objectives. We also present the design, implementation, and evaluation of Morpheus as an extension to the XORP software router. Index Terms—BGP, interdomain routing, policy, configuration, analytic hierarchy process (AHP)

The Internet routing system today is divided into two views:...

Route-Reflection and confederations were introduced to alleviate the scalability issue of maintaining a full-mesh of iBGP sessions. However, these techniques may lead to routing, forwarding, route diversity and sub-optimal routing issues. In this paper, we propose a new scalable internal BGP route distribution architecture that is rid of these issues. We propose an iBGP route distribution architecture relying on Route Servers (RS). Compared to the work of Ceasar et al. [1], there are multiple RSs per AS in our proposal. This ensures scalability and robustness of our new internal BGP route distribution architecture. Each route server is responsible for a subset of the external destinations. For this subset, the RS selects the egress ASBR to be used by each router in the AS. 2

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Internet Service Providers (ISPs) are the core building blocks of the Internet, and play a crucial role in keeping the Internet well-connected and stable, as well as providing services that meet the needs of other ASes (and their users). As a result, an ISP plays different roles in its operation: (1) as part of the Internet, an ISP is expected to help keep the global network stable; (2) when interacting with neighboring networks, an ISP faces diverse requirements from different neighbors about the kinds of routes they prefer; and (3) internally, an ISP needs to maintain and upgrade its own network periodically, and wants avoid disruptions during those operations as much as possible. As the Internet has become an integral part of the world’s communications infrastructure, today’s ISPs face a number of routing management challenges at these different scopes, which include: (i) maintaining the stability of the global Internet while meeting the increasingly demands for providing diverse routes from its customers, (ii) supporting more flexible routing policy configuration in bilateral contractual relationships with its neighbors, and (iii) making network maintenance and other network management operations in their own networks easier and less disruptive to routing protocols and data traffic. This dissertation takes a principled approach to addressing these challenges. We propose three

Abstract—Internal BGP (iBGP) is used to distribute interdomain routes within a single ISP. The interaction between iBGP and the underlying IGP can lead to routing and forwarding anomalies. For this reason, several research contributions aimed at defining sufficient conditions to guarantee anomaly-free configurations and providing design guidelines for network operators. In this paper, we show several anomalies caused by defective dissemination of routes in iBGP. We define the dissemination correctness property, which models the ability of routers to learn at least one route to each destination. By distinguishing between dissemination correctness and existing correctness properties, we show counterexamples that invalidate some results in the literature. Further, we prove that deciding whether an iBGP configuration is dissemination correct is computationally intractable. Even worse, determining whether the addition of a single iBGP session can adversely affect dissemination correctness of an iBGP configuration is also computationally intractable. Finally, we provide sufficient conditions that ensure dissemination correctness, and we leverage them to both formulate design guidelines and revisit prior results. I.

Due to the way BGP paths are distributed over iBGP sessions inside an Autonomous System (AS), a BGP withdraw that follows a failure may be propagated outside the AS although other routers of the AS know a valid alternate path. This causes transient losses of connectivity and contributes to the propagation of a large number of unnecessary BGP messages. In this paper, we show, based on RouteViews data, that a significant number of BGP withdraws are propagated even though alternate paths exists in another border router of the same AS. We propose an incrementally deployable solution based on BGP communities that allows the BGP routers of an AS to suspend the propagation of BGP withdraws when an alternate path is available at the borders of their AS.