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Bjornstad S.,Norwegian University of Science and Technology | Veisllari R.,Norwegian University of Science and Technology | Braute J.P.,TransPacket | Bozorgebrahimi K.,UNINETT
Optics InfoBase Conference Papers | Year: 2014

We report aggregation of sub-wavelengths in an integrated packet/circuit hybrid optical network. Aggregation of packet streams with circuit quality of service combined with statistical multiplexing enables packet delay variation of only 15ns at 82.4% throughput. © OSA 2014.


Veisllari R.,TransPacket | Veisllari R.,Norwegian University of Science and Technology | Bjornstad S.,TransPacket | Bjornstad S.,Norwegian University of Science and Technology | And 3 more authors.
European Conference on Optical Communication, ECOC | Year: 2015

Add/drop with sub-wavelength granularity is demonstrated in an integrated hybrid optical network Ethernet test-bed. Ultra-low packet delay variation (PDV), 300ns peak, is achieved for high wavelength utilization of 88% using additional statistical multiplexing. © 2015 Viajes el Corte Ingles, VECISA.


Myakotnykh E.S.,Norwegian University of Science and Technology | Helvik B.E.,Norwegian University of Science and Technology | Wittner O.J.,UNINETT | Kvittem O.,UNINETT | And 3 more authors.
IEEE International Workshop on Quality of Service, IWQoS | Year: 2010

This paper presents an analysis of measurements on a global route between Norway and China. Measurement statistics was collected every 10 milliseconds during a three-month period in October-December 2009. We provide a detailed characterization of observed loss and delay patterns especially focusing on downtime periods on the sub-second time scale (from 50 milliseconds to 1 second long). Generally, these downtimes are more difficult to measure, but they may also have a noticeable negative effect on quality of real-time services and multimedia applications. The paper investigates causes for all these events and finds that the plausible causes most of observed communication problems in the given study are either link or router related (level 2 or 3). Packet loss events caused by congestion could also be distinguished, but they happened very rarely. Using the collected data set, we also study several other questions related to routing and network availability modeling.


Bjornstad S.,Norwegian University of Science and Technology | Veisllari R.,Norwegian University of Science and Technology | Bozorgebrahimi K.,UNINETT
Optical Fiber Communication Conference, OFC 2013 | Year: 2013

In the first integrated packet/circuit hybrid network field-trial with production traffic, the mean capacity utilization of an Ethernet wavelength during a 24h period is doubled without timing-impact on the wavelength traffic. © OSA 2013.


Veisllari R.,Norwegian University of Science and Technology | Bjornstad S.,Norwegian University of Science and Technology | Bozorgebrahimi K.,UNINETT
2013 Optical Fiber Communication Conference and Exposition and the National Fiber Optic Engineers Conference, OFC/NFOEC 2013 | Year: 2013

We report the first field-trial of an integrated packet/circuit hybrid optical network. Bypassing routers with circuit quality of service and network throughput of 99% is demonstrated on a shared packet/circuit layer lightpath. © 2013 OSA.


Ma H.,Norwegian University of Science and Technology | Helvik B.E.,Norwegian University of Science and Technology | Wittner O.J.,UNINETT
Journal of Communications and Networks | Year: 2011

The inter-domain routing scalability issue is a major challenge facing the Internet. Recent wide deployments of multihoming and traffic engineering urge for solutions to this issue. So far, tunnel-based proposals and compact routing schemes have been suggested. An implicit assumption in the routing community is that structured address labels are crucial for routing scalability. This paper first systematically examines the properties of identifiers and address labels and their functional differences. It develops a simple Internet routing model and shows that a binary relation T defined on the address label set A determines the cardinality of the compact label set L. Furthermore, it is shown that routing schemes based on fiat address labels are not scalable. This implies that routing scalability and routing stability are inherently related and must be considered together when a routing scheme is evaluated. Furthermore, a metric is defined to measure the efficiency of the address label coding. Simulations show that given a 3000-autonomous system (AS) topology, the required length of address labels in compact routing schemes is only 9.12 bits while the required length is 10.64 bits for the Internet protocol (IP) upper bound case. Simulations also show that the a values of the compact routing and IP routing schemes are 0.80 and 0.95, respectively, for a 3000-AS topology. This indicates that a compact routing scheme with necessary routing stability is desirable. It is also seen that using provider allocated IP addresses in multihomed stub ASs does not significantly reduce the global routing size of an IP routing system. © 2011 KICS.


Ma H.,Norwegian University of Science and Technology | Helvik B.E.,Norwegian University of Science and Technology | Wittner O.J.,UNINETT
3rd Int. Conf. on Communication Theory, Reliability, and Quality of Service, CTRQ 2010, Includes MOPAS 2010: 1st Int. Conf. on Models and Ontology-Based Design of Protocols, Architecture and Services | Year: 2010

Due to the wide deployment of multi-homing and traffic engineering, inter-domain routing scalability issue has been raised again. Although many existing schemes have been suggested based on the explicit/implicit routing aggregation, it is shown that any routing scheme relying on routing aggregation does not work well for a small world graph. Many studies on stationary performance of the compact routing schemes showed the promising results in terms of routing stretch, their performance upon network dynamics has not been studied yet. Thus, the routing scalability is still an open issue. The name-independent compact routing scheme is based on name-dependent compact routing schemes. Thus, it is significant to investigate the dynamic performance of name-dependent compact routing schemes upon network dynamics of the inter-domain network. This paper is the first of this type of work. By studying Cowen's scheme and TZ's scheme, we find a tendency that both the number of autonomous systems (ASs) changing their landmark ASs and the number of new selected landmark ASs upon a landmark AS failure increase strongly with the degrees of failed landmark ASs. The services concerning ASs that change their landmark ASs are not available during network reconfiguration. The result also sheds light on the stability of all name-dependent compact routing schemes: the stability highly relies on how many ASs choose an AS as their landmark AS and how reliable the landmark AS is. © 2010 IEEE.


Abdelkefi A.,Norwegian University of Science and Technology | Jiang Y.,Norwegian University of Science and Technology | Wei W.,University of Luxembourg | Aslebo A.,UNINETT | Kvittem O.,UNINETT
Proceedings of the ACM CoNEXT Student Workshop, CoNEXT 2010 | Year: 2010

Principal component analysis (PCA) is a statistical technique that has been used for data analysis and dimensionality reduction. It was introduced as a network traffic anomaly detection technique firstly in [1]. Since then, a lot of research attention has been received, which results in an extensive analysis and several extensions. In [2], the sensitivity of PCA to its tuning parameters, such as the dimension of the low-rank sub-space and the detection threshold, on traffic anomaly detection was indicated. However, no explanation on the underlying reasons of the problem was given in [2]. In [3], further investigation on the PCA sensitivity was conducted and it was found that the PCA sensitivity comes from the inability of PCA to detect temporal correlations. Based on this finding, an extension of PCA to Kalman-Loeve expansion (KLE) was proposed in [3]. While KLE shows slight improvement, it still exhibits similar sensitivity issue since a new tuning parameter called temporal correlation range was introduced. Recently, in [4], additional effort was paid to illustrate the PCA-poisoning problem. To underline this problem, an evading strategy called Boiled-Frog was proposed which adds a high fraction of outliers to the traffic. To defend against this, the authors employed a more robust version of PCA called PCA-GRID. While PCA-GRID shows performance improvement regarding the robustness to the outliers, it experiences a high sensitivity to the threshold estimate and the k-dimensional subspace that maximizes the dispersion of the data. The purpose of this work is to consider another technique to address the PCA poisoning problems to provide robust traffic anomaly detection: The Principal Component Pursuit. © 2010 ACM.


Myakotnykh E.S.,Norwegian University of Science and Technology | Helvik B.E.,Norwegian University of Science and Technology | Hellan J.K.,UNINETT | Kvittem O.,UNINETT | And 3 more authors.
2010 International Congress on Ultra Modern Telecommunications and Control Systems and Workshops, ICUMT 2010 | Year: 2010

With the objective to better understand how the global Internet should achieve an availability in the order of five nines, i.e. be available 0.99999 of the time, active measurements were performed between Norway and China through the Global Research Network. End-to-end downtime statistics was continuously collected during a 3-month period up to mid February 2010. In addition to periodically sending probe packets between the two measurement systems, traceroute was used every two minutes to identify an exact IP-level path between the endpoints. Also, TTL (time-to-live) counter in the IP-header, which is reduced by one on every hop, was analyzed for each packet. Causes of the observed network failures based on the collected data were identified and insight is gained into processes preceding and following communication downtimes. We distinguish inter- and intradomain failures and, when possible, identify an exact link or an Autonomous System where a certain event has happened. The study shows that the end-to-end path availability is mainly affected by interdomain failures and long BGP convergence time as well as series of events not straight forwardly explained by the anticipated (re)routing behavior. ©2010 IEEE.


Wittner O.J.,UNINETT | Helvik B.E.,Norwegian University of Science and Technology | Abdelkefi A.,Norwegian University of Science and Technology | Hellan J.K.,UNINETT | And 3 more authors.
Telecommunication Systems | Year: 2013

With the objective to better understand how the global Internet should achieve an availability in the order of "five nines", i.e. be available 0.99999 of the time, active measurements were performed between Norway and China through the Global Research Network. End-to-end downtime statistics were collected during two 3-month periods, mid November 2009 till mid February 2010 and July 2010 till September 2010. Probe packets were sent every 10 ms between the two measurement systems supplemented by traceroute measurements every two minutes. The collected data (TTL, timestamps, sequence numbers and traceroute output) enabled identification and characterization of IP-level paths between the end-points. Causes of observed network failures were identified and insight is gained into processes preceding and following communication downtimes. We distinguish inter- and intradomain failures and, when possible, identify an exact link or an Autonomous System where a certain event has happened. The study shows that the end-to-end path availability is mainly affected by interdomain failures and long BGP convergence time as well as series of events not straight forwardly explained by the anticipated (re)routing behavior. © 2011 Springer Science+Business Media, LLC.

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