@article {Simula.simula.704,
	title = {BGP Churn Evolution: a Perspective From the Core},
	journal = {IEEE/ACM Transactions on Networking},
	volume = {20},
	number = {2},
	year = {2012},
	month = {April},
	pages = {571-584},
	abstract = {The scalability limitations of BGP have been a major concern lately. An important aspect of this issue is the rate of routing updates (churn) that BGP routers must process. This paper presents an analysis of the evolution of churn in four networks at the backbone of the Internet over a period of seven years and eight months, using BGP update traces from the RouteViews project. The churn rate varies widely over time and between networks. Instead of descriptive {\textquoteleft}{\textquoteleft}black-box{\textquoteright}{\textquoteright} statistical analysis, we take an exploratory data analysis approach attempting to understand the reasons behind major observed characteristics of the churn time series. We find that duplicate announcements is a major churn contributor, responsible for most large spikes. Remaining spikes are mostly caused by routing incidents that affect a large number of prefixes simultaneously. More long-term intense periods of churn, on the other hand, are caused by misconfigurations or other special events at or close to the monitored AS. After filtering pathologies and effects that are not related to the long-term evolution of churn, we analyze the remaining {\textquoteleft}{\textquoteleft}baseline{\textquoteright}{\textquoteright} churn and find that it is increasing at a rate that is similar to the growth of the number of Autonomous Systems.},
	author = {Elmokashfi, Ahmed and Kvalbein, Amund and Dovrolis, Constantine}
}
@inproceedings {Simula.simula.706,
	title = {SIMROT: a Scalable Inter-Domain Routing Toolbox},
	journal = {SIGMETRICS Perform. Eval. Rev.},
	volume = {39},
	number = {2},
	year = {2011},
	month = {September},
	pages = {4-13},
	publisher = {ACM},
	type = {Conference},
	abstract = {BGP plays a crucial role in the global communications in-frastructure, and there is a strong need for tools that can be used for analyzing its performance under different scenarios. The size and complexity of the inter-domain routing system often makes simulation the only viable method for such studies. This work addresses the lack of a comprehensive toolbox to simulate BGP. It proposes a flexible topology generator that produces AS-level graphs which are annotated with business relationships. The second component of the toolbox is a light-weight BGP simulator that is capable of capturing routing dynamics, while scaling to network sizes of thousands of nodes. We employ our frame- work to investigate a set of what-if questions concerning the impact of different topology parameters on BGP dynamics. This investigation shows how our proposed framework can help in gaining important insights on inter-domain routing dynamics.},
	isbn = {0163-5999},
	doi = {http://doi.acm.org/10.1145/2034832.20348},
	author = {Elmokashfi, Ahmed and Kvalbein, Amund and Dovrolis, Constantine}
}
@inproceedings {Simula.nd.435,
	title = {BGP Churn Evolution: a Perspective From the Core.},
	journal = {2010 Proceedings IEEE INFOCOM},
	year = {2010},
	publisher = {IEEE},
	type = {Conference},
	abstract = {The scalability limitations of BGP have been a major concern in the networking community lately. An important issue in this respect is the rate of routing updates (churn) that BGP routers must process. This paper presents an analysis of the evolution of churn in four networks in the backbone of the Internet over the last six years, using update traces from the Routeviews project. The churn rate varies widely over time and between networks, and cannot be understood through {\textquoteleft}{\textquoteleft}black-box{\textquoteright}{\textquoteright} statistical analysis. Instead we take a different approach with a focus on investigating the underlying reasons for BGP churn evolution. Through our analysis we are able to identify and isolate the main reasons behind many of the anomalies in the churn time series. We find that duplicate announcements is a major churn contributor, and responsible for most large spikes in the churn time series. Other intense periods of churn are caused by misconfigurations or other special events in or close to the monitored AS, and hence limiting these is an important mean to limit churn. We then analyze the remaining {\textquoteleft}{\textquoteleft}baseline{\textquoteright}{\textquoteright} churn, and find that it is increasing with a rate much slower than the increase in the routing table size.},
	isbn = {978-1-4244-5838-7},
	author = {Elmokashfi, Ahmed and Kvalbein, Amund and Dovrolis, Constantine},
	editor = {Mandyam, Giridhar and Westphal, Cedric}
}
@article {Simula.netsys.6,
	title = {On the Scalability of BGP: the Role of Topology Growth},
	journal = {IEEE Journal on Selected Areas in Communications},
	volume = {28},
	number = {8},
	year = {2010},
	note = {Special issue on Internet Routing Scalability.},
	month = {October},
	pages = {1250-1261},
	abstract = {The scalability of BGP routing is a major concern for the Internet community. Scalability is an issue in two different aspects: increasing routing table size, and increasing rate of BGP updates. In this paper, we focus on the latter. Our objective is to characterize the churn increase experienced by ASes in different levels of the Internet hierarchy as the network grows. We look at several {\textquoteleft}{\textquoteleft}what-if{\textquoteright}{\textquoteright} growth scenarios that are either plausible directions in the evolution of the Internet or educational corner cases, and investigate their scalability implications and interaction with different failure types. Our findings explain the dramatically different impact of multihoming and peering on BGP scalability, highlight negative and positive effects of multihoming on churn and reachability, and identify which topological growth scenarios will lead to faster churn increase for different failure types.},
	doi = {10.1109/JSAC.2010.101003},
	author = {Elmokashfi, Ahmed and Kvalbein, Amund and Dovrolis, Constantine}
}
@misc {Simula.nd.437,
	title = {BGP Churn Evolution: a Perspective From the Core},
	howpublished = {Poster, Trilogy Summer School, Louvain-la-Neuve, Belgium},
	year = {2009},
	author = {Elmokashfi, Ahmed and Kvalbein, Amund and Dovrolis, Constantine}
}
@inproceedings {Simula.ND.353,
	title = {Multipath Load-Adaptive Routing: Putting the Emphasis on Robustness and Simplicity},
	journal = {Proceedings ICNP 2009},
	year = {2009},
	publisher = {IEEE},
	type = {Conference},
	abstract = {We propose a routing and load-balancing approach with the primary goal of being robust to sudden topological changes and significant traffic matrix variations. The proposed method load-balances traffic over several routes in an adaptive way based on its local view of the load in the network. The focus is on robustness and simplicity, rather than optimality, and so it does not rely on a given traffic matrix, nor it is tuned to a specific topology. Instead, we aim to achieve a satisfactory routing under a wide range of traffic and topology scenarios based on each node\&$\#$39;s independent operation. The scheme avoids the instability risks of previous load-responsive routing schemes, it does not load the control plane with congestion-related signaling, and it can be implemented on top of existing routing protocols. In this paper, we present the proposed scheme, discuss how it aims to meet the objectives of robustness and load-responsiveness, and evaluate its performance under diverse traffic loads and topological changes with flow-level simulations.},
	isbn = {xx},
	author = {Kvalbein, Amund and Dovrolis, Constantine and Muthu, Chidambaram}
}
@inproceedings {Simula.ND.217,
	title = {On the Scalability of BGP: the Roles of Topology Growth and Update Rate-Limiting},
	journal = {CoNext 2008},
	year = {2008},
	publisher = {ACM},
	type = {Conference},
	abstract = {The scalability of BGP routing is a major concern for the Internet community. Scalability is an issue in two different aspects: increasing routing table size, and increasing rate of BGP updates. In this paper, we focus on the latter. Our objective is to characterize the churn increase experienced by ASes in different levels of the Internet hierarchy as the network grows. We look at several {\textquoteleft}{\textquoteleft}what-if\&$\#$39;\&$\#$39; growth scenarios that are either plausible directions in the evolution of the Internet or educational corner cases, and investigate their scalability implications. In addition, we examine the effect of the BGP update rate-limiting timer (MRAI), considering both major variations with which it has been deployed. Our findings explain the dramatically different impact of multihoming and peering on BGP scalability, identify which topological growth scenarios will lead to faster churn increase, and emphasize the importance of not rate-limiting explicit withdrawals (despite what RFC-4271 recently required).},
	isbn = {00000000},
	author = {Elmokashfi, Ahmed and Kvalbein, Amund and Dovrolis, Constantine}
}
