Buffers temporary can store data in terminals and switching systems of communication networks. When data is arriving faster than it can be processed then buffering is useful in order to avoid dropping a part of it. On the other hand, buffers in network elements introduce additional delay which limits their efficiency for real time data transfers. Sender buffers help to reduce the variability of source traffic profiles and may transform a variable rate input stream into a constant rate output. In terminals, buffers are necessary to adjust different delays (delay jitter) of received data units for real time service and to hold it available until the play out time as well as for reordering out of sequence packets for transport protocols like TCP.
Published in Chapter:
Network Planning and Dimensioning for Broadband Access to the Internet Regarding Quality of Service Demands
Franz Hartleb (T-Systems, Germany), Gerhard Haßlinger (T-Systems, Germany), and Sebastian Kempken (University of Duisburg-Essen, Germany)
Copyright: © 2009
|Pages: 15
DOI: 10.4018/978-1-60566-194-0.ch054
Abstract
An ongoing challenge in telecommunication is the integration of a variety of services on broadband access platforms at increasing transmission speed. Traditional Internet services like file transfer, email and web browsing, are carried on the same multi service IP platforms with voice, video and television over IP, online gaming, peer-to-peer and grid networking etc. While broadband access is established as a standard equipment for homes, the networking capacities in the access and the backbone are steadily extended to keep pace with higher traffic volumes. Together with the spectrum of services, the traffic mix on the aggregation levels becomes increasingly versatile with different demands for end-to-end transport in terms of throughput, loss and delay sensitivity. The chapter focuses on planning and traffic engineering for link bandwidth and buffers as main resources in communication platforms based on measurement and statistical properties of traffic growth and variability. We summarize quality of service demands of main Internet applications and mechanisms to control and stabilize the performance of ISP network platforms on different time scales. Load thresholds for link dimensioning are derived with regard to quality of service (QoS) demands and the variability in source and aggregated profiles. Finally, link level and network wide traffic engineering is addressed together with load balancing techniques.