Providing scalable NH-diverse iBGP route re-distribution to achieve sub-second switch-over time

The role of BGP inside an AS is to disseminate the routes learned from external peers to all routers of the AS. A straightforward, but not scalable, solution, is to resort to a full-mesh of iBGP sessions between the routers of the domain. Achieving scalability in the number of iBGP sessions is possible by using Route Reflectors (RR). Relying on a sparse iBGP graph using RRs however has a negative impact on routers’ ability to quickly switch to an alternate route in case of a failure. This stems from the fact that routers do not often know routes towards distinct next-hops, for any given prefix.In this paper, we propose a solution to build sparse iBGP topologies, where each BGP router learns two routes with distinct next-hops (NH) for each prefix. We qualify such iBGP topologies as NH-diverse. We propose to leverage the “best-external” option available on routers. By activating this option, and adding a limited number of iBGP sessions to the existing iBGP topology, we obtain NH-diverse iBGP topologies that scale, both in number of sessions and routing table sizes. We show that NH diversity enables to achieve sub-second switch-over time upon the failure of an ASBR or interdomain link. The scalability of our approach is confirmed by an evaluation on a research and a Service Provider network.     

Modeling the routing of an autonomous system with C-BGP

Today, the complexity of ISPs' networks make it difficult to investigate the implications of internal or external changes on the distribution of traffic across their network. In this article we explain the complexity of building models of large ISPs' networks. We describe the various aspects important to understanding the routing inside an AS. We present an open source routing solver, C-BGP, that eases the investigation of changes in the routing or topology of large networks. We illustrate how to build a model of an ISP on a real transit network and apply the model on two "what-if" scenarios. The first scenario studies the impact of chances in the Internet connectivity of a transit network. The second investigates the impact of failures in its internal topology.     

Interdomain traffic engineering with BGP

Traffic engineering is performed by means of a set of techniques that can be used to better control the flow of packets inside an IP network. We discuss the utilization of these techniques across interdomain boundaries in the global Internet. We first analyze the characteristics of interdomain traffic on the basis of measurements from three different Internet service providers and show that a small number of sources are responsible for a large fraction of the traffic. Across interdomain boundaries, traffic engineering relies on a careful tuning of the route advertisements sent via the border gateway protocol. We explain how this tuning can be used to control the flow of incoming and outgoing traffic, and identify its limitations.     

Impact of routing parameters on route diversity and path inflation

Years after the initial development of the current routing protocols we still lack an understanding of the impact of various parameters on the routes chosen in today’s Internet. Network operators are struggling to optimize their routing, but the effectiveness of those efforts is limited.In this article, we study sensitivity of routing stretch and diversity metrics to factors such as policies, topology, IGP weights, etc. using statistical techniques. We confirm previous findings that routing policies and AS size (in number of routers) are the dominating factors. Surprisingly, we find that intra-domain factors only have marginal impact on global path properties.Moreover, we study path inflation by comparing against the paths that are shortest in terms of AS-level/router-level hops or geographic distances. Overall, the majority of routes incur reasonable stretch. From the experience with our Internet-scale simulations, we find it hard to globally optimize path selection with respect to the geographic length of the routes, as long as inter-domain routing protocols do not include an explicit notion of geographic distance in the routing information.     

A performance evaluation of BGP‐based traffic engineering

Many Internet Service Providers tune the configuration of the Border Gateway Protocol on their routers to control their traffic. Content providers often need to control their outgoing traffic while access providers need to control their incoming traffic. We show, by means of measurements and simulations, that controlling the flow of the incoming interdomain traffic is a difficult problem. For this purpose, we first rely on detailed measurements to show the limitations of AS‐Path prepending. Then, we show by using large‐scale simulations that the difficulty of controlling the flow of the incoming traffic lies in the difficulty of predicting which BGP route will be selected by distant Autonomous Systems (ASs). Copyright © 2005 John Wiley & Sons, Ltd.     

Thorough Performance Evaluation & Analysis of the 6TiSCH Minimal Scheduling Function (MSF)

Journal of Signal Processing Systems - IEEE Std 802.15.4-2015 Time Slotted Channel Hopping (TSCH) is the de facto Medium Access Control (MAC) mechanism for industrial applications. It renders...     

Towards a bipartite graph modeling of the internet topology

Modeling the properties of the Internet topology aims at generating large scale artificial IP networks that mimic properties of real ones for simulation purposes. Current models typically consider the Internet as a simple graph where edges are point-to-point connections between routers. This approach does not take into account point-to-multipoint connections that exist at lower layers in the network, e.g. layer-2 clouds, such as Ethernet switches or MPLS networks. Instead, such physical point-to-multipoint connections are modeled as several logical IP level point-to-point connections.