Discussion Papers

Patrick Anell , Stephan Jay , Thomas Plückebaum

Nachfrage nach Internetdiensten – Dienstearten, Verkehrseigenschaften und Quality of Service

Nr. 302 / Dezember 2007

Summary

The volume of Internet traffic has risen considerably in recent years. Services are changing with the increasing availability of broadband access and operators must address the migration to a Next Generation Network to realise efficient structures for current and future service provision. In this context the requirements of broadband services differ fundamentally from those of narrowband voice because of their heterogeneous nature. Primary differences are related to requirements for quality, bandwidth and the distribution of daily traffic and its peak. This study assesses the requirements posed by established and emerging services to quality of service and how quality of service can be realised in current and future network architectures. The report then deducts impact factors and strategies for network dimensioning and structures from the requirements of current and emerging services. In order to comprehend the demand side orientated development of the market as well as the short-medium term requirements that are posed to planners of network infrastructures the characteristics of Internet services are analysed. Accordingly the study identifies most influential services and quantifies them according to their current usage. Furthermore application-specific user profiles are evaluated to enable an assessment of the impacts on network dimensioning.

In addition to demand-side usage patterns the analysis of network design must take the technical requirements for Quality of Service into account. Therefore the traffic characteristics are analysed and the different requirements of applications with respect to bandwidth, real-time character and symmetry are described. It is shown how applications may be allocated to appropriate classes of services and that some applications are heterogeneous by nature and cannot easily be allocated to a single class. Following this the study describes different instruments for realising Quality of Service on ATM, Ethernet and IP level, as it is expected that Ethernet will replace ATM technology in aggregation networks. The report underlines that standardized quality assurances in the NGN (through Ethernet/IP) are more limited than the options available through ATM. Finally the study details strategies for planning the dimension of narrowband PSTN networks and compares them with those for broadband networks drawing on the preceding analysis of usage profiles, applications-specific technical requirements and strategies for implementing Quality of Service. It is shown that the extension of broadband infrastructures pose a challenge for operators considering that architectures must allow for a flexible facilitation of different traffic types whilst preserving applicationspecific Quality of Service.

It is concluded that there remains need for further research with regard to identifying and allocating the costs for differentiated qualities in order to direct network usage according to economical principles. [only a german version avaiable]

Discussion Paper is available for download.

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