IP Backbone Network Research Articles

On Internet backbone traffic modeling

The motivation of this work is to design a traffic model that can be used in routers or by network administrators to assist in network design and management. Currently, network operators have very basic information about the traffic. They mostly use SNMP, which provides average throughput information over 5 minutes intervals. An analytical model can provide more accurate information on the traffic such as its variation and its auto-correlation at short timescales.In contrast to other works (see [2] and the references therein), we choose to model the traffic on a link that is not congested (congestion possibly appears elsewhere in the Internet). This assumption is valid (and in fact is the rule) for backbone links that are generally over-provisioned (i.e., the network is designed so that a backbone link does not reach 50% utilization in the absence of link failure [4]). This choice is driven by our main objective, which is to provide a link dimensioning tool usable in backbone network management.We opt for a model of the traffic at the flow level. Modeling the traffic at the packet level is very difficult, since traffic on a link is the result of a high level of multiplexing of numerous flows whose behavior is strongly influenced by the transport protocol and by the application. A flow in our model is a very generic notion. It can be a TCP connection or a UDP stream (described by source and destination IP addresses, source and destination port numbers and the protocol number), or it can be a destination address prefix (e.g., destination IP address in the form a.b.0.0/16). The definition of a flow is deliberately kept general, which allows our model to be applied to different applications and to different transport mechanisms. The model can however be specified to some particular traffic types such as FTP and HTTP. By specifying the model to a certain traffic type, one must expect to obtain better results.Data flows arrive to a backbone link at random times, transport a random volume of data, and stay active for random periods. Given information on flows, our model aims to compute the total (aggregate) rate of data observed on the backbone link. We are interested in capturing the dynamics of the total data rate at short timescales (i.e., of the order of hundreds of milliseconds). This dynamics can be completely characterized using simple mathematical tools, namely the shot-noise process [3]. Our main contribution is the computation of simple expressions for important measures of backbone traffic such as its average, its variance, and its auto-correlation function. These expressions are functions of a few number of parameters that can be easily computed by a router (e.g., using a tool such as NetFlow, which provides flow information in Cisco routers).Our model can be helpful for managing and dimensioning IP backbone networks. Knowing the average and the variance of the traffic allows an ISP to provision the links of its backbone so as to avoid congestion. Congestion can be avoided at short timescales of the order of hundreds of milliseconds. The auto-correlation function of the traffic can be used to propose predictors for its future values. The prediction of the traffic has diverse applications in managing the resources of the backbone. One interesting application is the use of a short-term prediction to optimize packet routing and load balancing. Our model can also be used to assess the impact on backbone traffic of changes made in the rest of the Internet such as the addition of a new customer, a new application, or a new transport mechanism. The ISP can plan the provisioning of its backbone so as to absorb the resulting change of traffic before this change takes place.

Resilience for IP-over-DWDM backbone networks

Given the extensive growth in Internet traffic and increasing emphasis on service quality, one of the most crucial elements of IP backbone network design is to provide resilience to serious failures such as fibre-optic cable breaks. In previous years, the unit of bandwidth granularity for many IP backbone networks has grown from STM-1 (155 Mbit/s) through to STM-16 (2.4 Gbit/s), with STM-64 (10 Gbit/s) backbone circuits becoming prevalent. The increased concentration of traffic makes the IP backbone extremely vulnerable to failure, meaning a key challenge is to engineer embedded resilience into the network. This paper considers such issues and discusses various trade-offs associated with different levels of protection in an IP backbone network.

Deriving traffic demands for operational IP networks: methodology and experience

Engineering a large IP backbone network without an accurate network-wide view of the traffic demands is challenging. Shifts in user behavior, changes in routing policies, and failures of network elements can result in significant (and sudden) fluctuations in load. We present a model of traffic demands to support traffic engineering and performance debugging of large Internet service provider networks. By defining a traffic demand as a volume of load originating from an ingress link and destined to a set of egress links, we can capture and predict how routing affects the traffic traveling between domains. To infer the traffic demands, we propose a measurement methodology that combines flow-level measurements collected at all ingress links with reachability information about all egress links. We discuss how to cope with situations where practical considerations limit the amount and quality of the necessary data. Specifically, we show how to infer interdomain traffic demands using measurements collected at a smaller number of edge links-the peering links connecting to neighboring providers. We report on our experiences in deriving the traffic demands in the AT&T IP Backbone, by collecting, validating, and joining very large and diverse sets of usage, configuration, and routing data over extended periods of time. The paper concludes with a preliminary analysis of the observed dynamics of the traffic demands and a discussion of the practical implications for traffic engineering.

General Packet Radio Service (GPRS): architecture, interfaces, and deployment

This article provides an overview of General Packet Radio Service (GPRS). GPRS reuses the existing GSM infrastructure to provide end-to-end packet-switched services. Benefits of GPRS include efficient radio usage, fast set-up/access time and high bandwidth with multiple timeslots. GPRS also provides a smooth path for GSM evolution to the third generation mobile network. Specifically, a third generation network can continue to utilize the GPRS IP backbone network. We describe the GPRS network nodes and the interfaces among these nodes. Deployment issues for GPRS are also elaborated. Copyright © 2001 John Wiley & Sons, Ltd.

Evaluation of IP over WDM Network Architectures

The commonly used IP-backbone network architecture of today is IP/ATM/SDH/WDM. This architecture has many redundant functionalities and is not optimized to transport IP traffic. New approaches for simplified network architectures try to eliminate redundant functionalities and to decrease the protocol overhead and thereby transport IP as efficiently as possible over WDM-based optical networks. EURESCOM project P918 “Integration of IP-over-optical networks: networking and management” investigated scenarios for optimized IP transport in WDM-based backbone networks. In this paper, three architectures, namely Gigabit Ethernet, Packet over Sonet/SDH and Dynamic Packet Transport are investigated and evaluated as an alternative to the IP/ATM/SDH/WDM architecture.

Deriving traffic demands for operational IP networks

Engineering a large IP backbone network without an accurate, network-wide view of the traffic demands is challenging. Shifts in user behavior, changes in routing policies, and failures of network elements can result in significant (and sudden) fluctuations in load. In this paper, we present a model of traffic demands to support traffic engineering and performance debugging of large Internet Service Provider networks. By defining a traffic demand as a volume of load originating from an ingress link and destined to a set of egress links, we can capture and predict how routing affects the traffic traveling between domains. To infer the traffic demands, we propose a measurement methodology that combines flow-level measurements collected at all ingress links with reachability information about all egress links. We discuss how to cope with situations where practical considerations limit the amount and quality of the necessary data. Specifically, we show how to infer interdomain traffic demands using measurements collected at a smaller number of edge links --- the peering links connecting to neighboring providers. We report on our experiences in deriving the traffic demands in the AT&T IP Backbone, by collecting, validating, and joining very large and diverse sets of usage, configuration, and routing data over extended periods of time. The paper concludes with a preliminary analysis of the observed dynamics of the traffic demands and a discussion of the practical implications for traffic engineering.

Photonic transport networks based on wavelength division multiplexing technologies

Restricted accessMoreSectionsView PDF ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmail Cite this article Sato Ken–Ichi 2000Photonic transport networks based on wavelength division multiplexing technologiesPhil. Trans. R. Soc. A.3582265–2281http://doi.org/10.1098/rsta.2000.0646SectionRestricted accessPhotonic transport networks based on wavelength division multiplexing technologies Ken–Ichi Sato Ken–Ichi Sato Photonic Transport Network Laboratory, NTT Network Innovation Laboratories, 1–1 Hikarino–oka, Yokosuka, Kanagawa, 239–0847, Japan () Google Scholar Find this author on PubMed Search for more papers by this author Ken–Ichi Sato Ken–Ichi Sato Photonic Transport Network Laboratory, NTT Network Innovation Laboratories, 1–1 Hikarino–oka, Yokosuka, Kanagawa, 239–0847, Japan () Google Scholar Find this author on PubMed Search for more papers by this author Published:15 August 2000https://doi.org/10.1098/rsta.2000.0646AbstractThis paper highlights recent advances in the development of photonic transport networks. The requirements of future networks are discussed and the photonic network envisaged is identified. The role of photonic technologies in enhancing network performance is elucidated. The attributes of the new optical layer, in terms of transport layer architecture, and function allocation are discussed. The IP backbone network based on optical path technologies is highlighted. Some cutting–edge technologies, such as supercontinuum light sources and a coherent optical amplifier, are demonstrated. Previous ArticleNext Article VIEW FULL TEXT DOWNLOAD PDF FiguresRelatedReferencesDetailsCited by Supercontinuum in Wavelength Division Multiplex Telecommunication The Supercontinuum Laser Source, 10.1007/0-387-25097-2_14, (498-504) (2001) Functional Materials The Coming of Materials Science, 10.1016/S1470-1804(01)80010-9, (253-304), . This Issue15 August 2000Volume 358Issue 1773Discussion Meeting Issue ‘Network modelling in the twenty–first century’ organized by P. Bayvel, R. J. Gibbens and J. E. Midwinter Article InformationDOI:https://doi.org/10.1098/rsta.2000.0646Published by:Royal SocietyPrint ISSN:1364-503XOnline ISSN:1471-2962History: Published online15/08/2000Published in print15/08/2000 License: Citations and impact Keywordsoptical pathIP backboneoptical layerphotonic networkphotonic technologiesWDM

NetScope: traffic engineering for IP networks

Managing large IP networks requires an understanding of the current traffic flows, routing policies, and network configuration. However, the state of the art for managing IP networks involves manual configuration of each IP router, and traffic engineering based on limited measurements. The networking industry is sorely lacking in software systems that a large Internet service provider can use to support traffic measurement and network modeling, the underpinnings of effective traffic engineering. This article describes the AT&T Labs NetScope, a unified set of software tools for managing the performance of IP backbone networks. The key idea behind NetScope is to generate global views of the network on the basis of configuration and usage data associated with the individual network elements. Having created an appropriate global view, we are able to infer and visualize the networkwide implications of local changes in traffic, configuration, and control. Using NetScope, a network provider can experiment with changes in network configuration in a simulated environment rather than the operational network. In addition, the tool provides a sound framework for additional modules for network optimization and performance debugging. We demonstrate the capabilities of the tool through an example traffic engineering exercise of locating a heavily loaded link, identifying which traffic demands flow on the link, and changing the configuration of intradomain routing to reduce the congestion.

Photonic transport technologies to create robust backbone networks

This article discusses the role of the new optical layer in terms of transport layer architecture and functional allocations. The envisaged future photonic network is identified, and the technologies needed to realize reliable communication are clarified. Network-node interface technologies, and network protection and restoration strategies are discussed in detail, since these are key to developing a network with high integrity that will be a main pillar of the future information society. Finally, applications of photonic network technologies and a network design example are presented; the IP backbone network based on optical path technologies is highlighted.

IP over SONET

IP over SONET technology is being deployed today in IP backbone networks to provide efficient, cost-effective, high-speed transport between fast routers. The authors present an overview of the architectural considerations in the deployment of IP over SONET technology. In addition, an overview of the developments in IP over SONET interface design and specification is provided. Finally, the authors conclude with an examination of the future of high-speed Internet transport.