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Cariden often presents at conferences (see the news/events page for a recent overview). On this page we provide a
selection of talks and papers by Cariden and its customers. Here is a sample of some of those papers:
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Traffic Engineering: Practical Strategies for IP Traffic Engineering and Enhancing Core network Availability Traffic Engineering Beyond MPLS IGPTuning in an MPLS Network Traffic Engineering through Automated Optimization of Routing Metrics Metric-Based Traffic Engineering: Panacea Or Snake Oil? A Real-World Study |
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Traffic Matrices: Traffic Matrices for IP Networks: NetFlow, MPLS, Estimation, Regression Traffic Matrix Estimation on a Large IP Backbone |
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Other: Backbone Traffic Management Peering Planning Cooperation Without Revealing Confidential Information |
Top Practical Strategies for IP Traffic Engineering and Enhancing Core network Availability Event: RIPE 48, May 2004, Amsterdam Speakers: John Evans (Cisco), Alan Gous (Cariden) Abstract: MPLS traffic engineering (TE) is often considered as synonymous with making more efficient use of network bandwidth and/or improving network availability via the capabilities of TE Fast Re-route (FRR). This session considers the theory behind traffic engineering in general, together with the benefits, limitations, and deployment considerations of MPLS TE in the context of IP traffic engineering and engineering core network availability. Consideration is also given to alternative technologies such as IGP metric based traffic engineering and IGP fast convergence, and to how quatitive decisions can be made on the relative benefits of the different approaches. 
Top Traffic Engineering Beyond MPLS Event: Apricot 2004, February 2005, Kuala Lumpur, Malaysia Speakers: Arman Maghbouleh (Cariden), John Evans (Cisco) Abstract: Most recent discussions of Traffic Engineering have centered on protocol enhancements for MPLS TE. In practice, however, TE is tightly bound with network topology and operational considerations. In this tutorial, we provide a practical overview of traditional pre-MPLS TE practices, MPLS options, and new computer-aided approaches.
Top IGP Tuning in an MPLS Network Event: NANOG 33, February 2005, Las Vegas Speaker: Martin Horneffer, T-Com Abstract: Much has been said about traffic engineering with explicit routing vs. tuning of IGP metrics. After a thorough analysis of alternatives, including a full mesh of static and/or dynamic RSVP-based tunnels, T-Com (AS3320) has decided to use the IGP metric-based approach of traffic engineering for its global IP/MPLS-based network. We show how we get the traffic matrix with a home-grown algorithm based on MPLS counters or "LDP statistics," thus avoiding the need for a full mesh of tunnels just to do the measurements. We also show how we represent the real network in a suitable way for simulation and optimization tools. Last but not least, we discuss some general design issues concerning the IGP metric design. General requirements for IGP metrics in the context of traffic engineering might easily contradict requirements for iBGP route reflection (see "BGP Persistent Route Oscillation Condition," RFC3345.)
Top Traffic Engineering through Automated Optimization of Routing Metrics Event: Terena Networking Conference, June 2004, Rhodes Authors: Thomas Telkamp (Global Crossing), Alan Gous (Cariden), Arash Afrakhteh (Cariden) Abstract: This presentation argues for the viability of metric-based traffic engineering (TE) in a pure IP network, as a simple alternative to MPLS tunnel-based TE. An overview of the steps required to perform metric-based TE are presented, with some special attention to demand estimation. A particular TE goal, reducing worst-case failure utilisation, is described formally. Metric-based TE is compared to alternatives in a study conducted on currently existing IP networks, using this criterion as a judge of performance.
Top Metric-Based Traffic Engineering: Panacea or Snake Oil? A Real-World Study Event: NANOG 26, October 2002, Phoenix Speaker: Arman Maghbouleh, Cariden Abstract: Recent research publications have noted the possibility that plain-old IGP metric manipulations may be as effective as the overlay-style traffic engineering made possible by ATM or MPLS. Adherents of either approach have pointed to specific topologies for which metric manipulation does extremely well or extremely poorly. Here, we present the results of a study comparing metric-based shortest-path routing with the theoretically optimal routing. We looked at six real networks under normal and single-circuit failures and found that, despite its limitations, metric-based routing was able to minimize maximum link utilizations about as well as the theoretical maximum. We present cases that illustrate the limitations of metric-based routing and speculate that these cases do not affect performance on existing networks because operators design networks with shortest-path routing limitations in mind.
Top Best Practices for Determining the Traffic Matrix in IP Networks Event: Apricot 2005, February 2005, Kyoto, Japan. Speaker: Thomas Telkamp (Cariden), Stefan Schnitter (T-Systems) Abstract: Knowledge of the amount of traffic between source and destination pairs of a network is crucial to fundamental operational tasks like capacity planning, traffic engineering, and peering management. Router vendors, third parties, and academic researchers, and ingenious network engineers have devised multiple ways of collecting and estimating traffic matrices. This talk presents an overview of applications of traffic matrices and operational experiences with the various approaches including Netflow based methods, mathematical estimation models, and MPLS (both RSVP and LDP) methods. Emphasis will be on practical experiences with each method.
Top Traffic Matrices for IP Networks: NetFlow, MPLS, Estimation, Regression Event: Preparing for the Future of the Internet, Network Information Center, Mexico, November 29, 2007 Speaker: Arman Maghbouleh, Cariden Abstract: Knowledge of the amount of traffic between source and destination pairs of a network is crucial to fundamental operational tasks such as capacity planning, traffic engineering, and peering management. Router vendors, third parties, academic researchers, and ingenious network engineers have devised multiple ways of collecting and estimating traffic matrices. This session presents an overview of applications of traffic matrices and operational experiences with the various approaches, including NetFlow-based methods, mathematical estimation models, and MPLS (both RSVP and LDP) methods. Emphasis will be on practical experiences with each method.
Top Traffic Matrix Estimation on a Large IP Backbone - A Comparison on Real Data Event: Internet Measurement Conference, October 2004, Sicily Authors: Anders Gunnar (SICS), Mikael Johansson (KTH), Thomas Telkamp (Global Crossing) Abstract: This paper considers the problem of estimating the point-to-point traffic matrix in an operational IP backbone. Contrary to previous studies, that have used a partial traffic matrix or demands estimated from aggregated Netflow traces, we use a unique data set of complete traffic matrices from a global IP network measured over five-minute intervals. This allows us to do an accurate data analysis on the time-scale of typical link-load measurements and enables us to make a balanced evaluation of different traffic matrix estimation techniques. We describe the data collection in- frastructure, present spatial and temporal demand distributions, investigate the stability of fan-out factors, and analyze the mean-variance relationships between demands. We perform a critical evaluation of existing and novel methods for traffic matrix estimation, including recursive fanout estimation, worst-case bounds, regularized estimation techniques, and methods that rely on mean-variance relationships. We discuss the weaknesses and strengths of the various methods, and highlight differences in the results for the European and American subnetworks
Top Backbone Traffic Management Event: Asia Pacific IP Experts Conference (Cisco), November 4th, 2003, Shanghai, P.R. China Author: Thomas Telkamp (Global Crossing) Abstract: Two main approaches exist today for providing quality of service (QoS) in IP backbones. One approach relies on scheduling/queuing; the other relies on the presence of capacity/bandwidth. The two schools of thought arise from different understandings of traffic characteristics. In this talk we present the results of an empirical study of Internet traffic characteristics. We use packet traces from a Tier-1 IP backbone network and introduce a non-parametric approach to study latency characteristics at high utilization levels. This approach requires minimal assumptions and has broad applicability. The 2nd part of the presentation is focused on the Network Planning framework, applying the derived guidelines to large IP networks. Topics covered include failure simulations, the role of Diff-Serv in the backbone, and traffic matrix estimation.
Top Peering Planning Cooperation Without Revealing Confidential Information Event: RIPE 52, April 2006, Istanbul, Turkey Author: Thomas Telkamp, Cariden Abstract: For most Internet Service Providers the majority of their traffic enters or leaves the network via BGP enabled peerings or upstream provider(s). Not only do these links need to have enough capacity during normal operation, they also need to provide redundant capacity during link failures. For the egress traffic (service provider to remote peer) this can be easily verified by simulating the rerouting under failure, as the topology of the network is completely known. The return traffic (remote peer to service provider) however can not be simulated, as the behaviour of the remote network is not known. This creates a gap in the planning process for external peering links. We present a simple methodology for creating 'Failover Matrices' that describe the traffic redistribution under peering link failure conditions. The matrices provide a useful mechanism for sharing information and improving the mutual planning process without disclosing any proprietary information. We will describe the principles behind the process as well as walk through a real scenario.
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