2006-11-01
Smart dimensioning of IP network links
Publication
Publication
Link dimensioning is generally considered as an effective and (operationally) simple mechanism
to meet (given) performance requirements. In practice, the required link capacity C is often
estimated by rules of thumb, such as C=dM, where M is the (envisaged) average traffic rate,
and d some (empirically determined) constant larger than 1. This paper studies the viability of
this class of `simplistic' dimensioning rules. Throughout, the performance criterion imposed is
that the fraction of intervals of length T in which the input exceeds the available output capacity
(i.e., CT) should not exceed epsilon, for given T and epsilon. We first present a dimensioning
formula that expresses the required link capacity as a function of M and a variance term V(T),
which captures the burstiness on timescale T. We explain how M and V(T) can be estimated
with low measurement effort. The dimensioning formula is then used to validate dimensioning
rules of the type C=dM. Our main findings are: (i) the factor d is strongly affected by the nature
of the traffic, the level of aggregation, and the network infrastructure; if these conditions are
more or less constant, one could empirically determine d; (ii)we can explicitly characterize how
d is affected by the "performance parameters", i.e., T and epsilon.
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CWI | |
CWI. Probability, Networks and Algorithms [PNA] | |
Organisation | Stochastics |
van de Meent, R., Mandjes, M., & Pras, A. (2006). Smart dimensioning of IP network links. CWI. Probability, Networks and Algorithms [PNA]. CWI. |