BGP-XM: BGP eXtended Multipath for Transit Autonomous Systems

Multipath interdomain routing has been proposed to enable flexible traffic engineering for transit Autonomos Systems (ASes). Yet, there is a lack of solutions providing maximal path diversity and backwards compatibility at the same time. The BGP-XM (Border Gateway Protocol-eXtended Multipath) extension presented in this paper is a complete and flexible approach to solve many of the limitations of previous BGP multipath solutions. ASes can benefit from multipath capabilities starting with a single upgraded router, and without any coordination with other ASes. BGP-XM defines an algorithm to merge into regular BGP updates information from paths which may even traverse different ASes. This algorithm can be combined with different multipath selection algorithms, such as the K-BESTRO (K-Best Route Optimizer) tunable selection algorithm proposed in this paper. A stability analysis and stable policy guidelines are provided. The performance evaluation of BGP-XM, running over an Internet-like topology, shows that high path diversity can be achieved even for limited deployments of the multipath mechanism. Further results for large-scale deployments reveal that the extension is suitable for large deployment since it shows a low impact in the AS path length and in the routing table size

A Neural Network Approach to Border Gateway Protocol Peer Failure Detection and Prediction

The size and speed of computer networks continue to expand at a rapid pace, as do the corresponding errors, failures, and faults inherent within such extensive networks. This thesis introduces a novel approach to interface Border Gateway Protocol (BGP) computer networks with neural networks to learn the precursor connectivity patterns that emerge prior to a node failure. Details of the design and construction of a framework that utilizes neural networks to learn and monitor BGP connection states as a means of detecting and predicting BGP peer node failure are presented. Moreover, this framework is used to monitor a BGP network and a suite of tests are conducted to establish that this neural network approach as a viable strategy for predicting BGP peer node failure. For all performed experiments both of the proposed neural network architectures succeed in memorizing and utilizing the network connectivity patterns. Lastly, a discussion of this framework\u27s generic design is presented to acknowledge how other types of networks and alternate machine learning techniques can be accommodated with relative ease

Optimal route reflection topology design

An Autonomous System (AS) is a group of Internet Protocol-based networks with a single and clearly defined external routing policy, usually under single ownership, trust or administrative control. The AS represents a connected group of one or more blocks of IP addresses, called IP prefixes, that have been assigned to that organization and provides a single routing policy to systems outside the AS. The Internet is composed of the interconnection of several thousands of ASes, which use the Border Gateway Protocol (BGP) to exchange network prefixes (aggregations of IP addresses) reachability advertisements. BGP advertisements (or updates) are sent over BGP sessions administratively set between pairs of routers. BGP is a path vector routing protocol and is used to span different ASes. A path vector protocol defines a route as a pairing between a destination and the attributes of the path to that destination. Interior Border Gateway Protocol (iBGP) refers to the BGP neighbor relationship within the same AS. When BGP neighbor relationship are formed between two peers belonging to different AS are called Exterior Border Gateway Protocol (eBGP). In the last case, BGP routers are called Autonomous System Border Routers (ASBRs), while those running only iBGP sessions are referred to as Internal Routers (IRs). Traditional iBGP implementations require a full-mesh of sessions among routers of each AS

Automated Formal Analysis of Internet Routing Configurations

Today\u27s Internet interdomain routing protocol, the Border Gateway Protocol (BGP), is increasingly complicated and fragile due to policy misconfigurations by individual autonomous systems (ASes). To create provably correct networks, the past twenty years have witnessed, among many other efforts, advances in formal network modeling, system verification and testing, and point solutions for network management by formal reasoning. On the conceptual side, the formal models usually abstract away low-level details, specifying what are the correct functionalities but not how to achieve them. On the practical side, system verification of existing networked systems is generally hard, and system testing or simulation provide limited formal guarantees. This is known as a long standing challenge in network practice --- formal reasoning is decoupled from actual implementation. This thesis seeks to bridge formal reasoning and actual network implementation in the setting of the Border Gateway Protocol (BGP), by developing the Formally Verifiable Routing (FVR) toolkit that combines formal methods and programming language techniques. Starting from the formal model, FVR automates verification of routing models and the synthesis of faithful implementations that carries the correctness property. Conversely, starting from large real-world BGP systems with arbitrary policy configurations, automates the analysis of Internet routing configurations, and also includes a novel network reduction technique that scales up existing techniques for automated analysis. By developing the above formal theories and tools, this thesis aims to help network operators to create and manage BGP systems with correctness guarantee

Proactive techniques for correct and predictable Internet routing

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, February 2006.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references (p. 185-193).The Internet is composed of thousands of autonomous, competing networks that exchange reachability information using an interdomain routing protocol. Network operators must continually reconfigure the routing protocols to realize various economic and performance goals. Unfortunately, there is no systematic way to predict how the configuration will affect the behavior of the routing protocol or to determine whether the routing protocol will operate correctly at all. This dissertation develops techniques to reason about the dynamic behavior of Internet routing, based on static analysis of the router configurations, before the protocol ever runs on a live network. Interdomain routing offers each independent network tremendous flexibility in configuring the routing protocols to accomplish various economic and performance tasks. Routing configurations are complex, and writing them is similar to writing a distributed program; the (unavoidable) consequence of configuration complexity is the potential for incorrect and unpredictable behavior. These mistakes and unintended interactions lead to routing faults, which disrupt end-to-end connectivity. Network operators writing configurations make mistakes; they may also specify policies that interact in unexpected ways with policies in other networks.(cont.) To avoid disrupting network connectivity and degrading performance, operators would benefit from being able to determine the effects of configuration changes before deploying them on a live network; unfortunately, the status quo provides them no opportunity to do so. This dissertation develops the techniques to achieve this goal of proactively ensuring correct and predictable Internet routing. The first challenge in guaranteeing correct and predictable behavior from a routing protocol is defining a specification for correct behavior. We identify three important aspects of correctness-path visibility, route validity, and safety-and develop proactive techniques for guaranteeing that these properties hold. Path visibility states that the protocol disseminates information about paths in the topology; route validity says that this information actually corresponds to those paths; safety says that the protocol ultimately converges to a stable outcome, implying that routing updates actually correspond to topological changes. Armed with this correctness specification, we tackle the second challenge: analyzing routing protocol configurations that may be distributed across hundreds of routers.(cont.) We develop techniques to check whether a routing protocol satisfies the correctness specification within a single independently operated network. We find that much of the specification can be checked with static configuration analysis alone. We present examples of real-world routing faults and propose a systematic framework to classify, detect, correct, and prevent them. We describe the design and implementation of rcc ("router configuration checker"), a tool that uses static configuration analysis to enable network operators to debug configurations before deploying them in an operational network. We have used rcc to detect faults in 17 different networks, including several nationwide Internet service providers (ISPs). To date, rcc has been downloaded by over seventy network operators. A critical aspect of guaranteeing correct and predictable Internet routing is ensuring that the interactions of the configurations across multiple networks do not violate the correctness specification. Guaranteeing safety is challenging because each network sets its policies independently, and these policies may conflict. Using a formal model of today's Internet routing protocol, we derive conditions to guarantee that unintended policy interactions will never cause the routing protocol to oscillate.(cont.) This dissertation also takes steps to make Internet routing more predictable. We present algorithms that help network operators predict how a set of distributed router configurations within a single network will affect the flow of traffic through that network. We describe a tool based on these algorithms that exploits the unique characteristics of routing data to reduce computational overhead. Using data from a large ISP, we show that this tool correctly computes BGP routing decisions and has a running time that is acceptable for many tasks, such as traffic engineering and capacity planning.by Nicholas Greer Feamster.Ph.D

MPLS layer 3 VPN

Trabalho final de mestrado para obtenção do grau de Mestre em Engenharia de Electrónica e TelecomunicaçõesMultiprotocol Label Switching (MPLS) is the principal technology used in Service Provider. Networks as this mechanism forwarding packet quickly. MPLS is a new way to increase the speed, capability and service supplying abilities for optimization of transmission resources. Service Provider networks use this technology to connect different remote sites. MPLS technology provides lower network delay, effective forwarding mechanism, ascendable and predictable performance of the services which makes it more appropriate for carry out real-time applications such as Voice and video. MPLS can be used to transport any type of data whether it is layer 2 data such as frame relay, Ethernet, ATM data etc. or layer 3 data such as IPV4, IPV6.Multiprotocol Label Switching (MPLS) é a principal tecnologia usada no Service Provider. Redes como este mecanismo fazem o encaminhamento de pacotes de dados rapidamente. MPLS é uma nova maneira de aumentar a velocidade, a capacidades de fornecimento, a capacidade de serviço para otimização de recursos de transmissão. As redes Service Provider usam essa tecnologia para ligar diferentes sites remotos. A tecnologia MPLS oferece menor atraso de rede, mecanismo de encaminhamento eficaz, desempenho e serviços previsíveis o que o tornam mais apropriado para executar aplicativos em tempo real, como voz e vídeo. O MPLS pode ser usado para transportar qualquer tipo de dados, seja dados de camada 2, como frame relay, Ethernet, dados ATM, etc., ou dados da camada 3, como IPV4, IPV6.N/

Inter-domain traffic management in and evolving Internet peering eco-system

Operators of the Autonomous Systems (ASes) composing the Internet must deal with constant traffic growth, while striving to reduce the overall cost-per-bit and keep an acceptable quality of service. These challenges have motivated ASes to evolve their infrastructure from basic interconnectivity strategies, using a couple transit providers and a few settlement-free peers, to employ geographical scoped transit services (e.g. partial transit) and multiplying their peering efforts. Internet Exchange Points (IXPs), facilities allowing the establishment of sessions to multiple networks using the same infrastructure, have hence become central entities of the Internet. Although the benefits of a diverse interconnection strategy are manifold, it also encumbers the inter-domain Traffic Engineering process and potentially increases the effects of incompatible interests with neighboring ASes. To efficiently manage the inter-domain traffic under such challenges, operators should rely on monitoring systems and computer supported decisions. This thesis explores the IXP-centric inter-domain environment, the managing obstacles arising from it, and proposes mechanisms for operators to tackle them. The thesis is divided in two parts. The first part examines and measures the global characteristics of the inter-domain ecosystem. We characterize several IXPs around the world, comparing them in terms of their number of members and the properties of the traffic they exchange. After highlighting the problems arising from the member overlapping among IXPs, we introduce remote peering, an interconnection service that facilitates the connection to multiple IXPs. We describe this service and measure its adoption in the Internet. In the second part of the thesis, we take the position of the network operators. We detail the challenges surrounding the control of inter-domain traffic, and introduce an operational framework aimed at facilitating its management. Subsequently, we examine methods that peering coordinators and network engineers can use to plan their infrastructure investments, by quantifying the benefits of new interconnections. Finally, we delve into the effects of conflicting business objectives among ASes. These conflicts can result in traffic distributions that violate the (business) interests of one or more ASes. We describe these interest violations, differentiating their impact on the ingress and egress traffic of a single AS. Furthermore, we develop a warning system that operators can use to detect and rank them. We test our warning system using data from two real networks, where we discover a large number of interest violations. We thus stress the need for operators to identify the ones having a larger impact on their network.This work has been supported by IMDEA Networks Institute.Programa Oficial de Doctorado en Ingeniería TelemáticaPresidente: Jordi Domingo-Pascual.- Secretario: Francisco Valera Pintor.- Vocal: Víctor Lópe