A method of dimensioning a link in a telecommunications network, the method comprising the steps of: determining, for a first set of traffic observations, wherein the first set includes a first series of traffic observations each indicating the amount of traffic on a link within an observation interval of a first duration, a peak value of a traffic observation of the first series of traffic observations and an average value of the first series of traffic observations; calculating a first peak to average ratio for the first set of traffic observations based on the determined peak and average values for the first set of traffic observations; the method characterised by: determining, for a second set of traffic observations, wherein the second set includes a second series of traffic observations each indicating the amount of traffic on the link within an observation interval of a second duration, a peak value of a traffic observation of the second series of traffic observations and an average value of the second series of traffic observations; calculating a second peak to average ratio for the second set of traffic observations based on the determined peak and average values for the second set of traffic observations; determining a goodness of fit value for a power function of the first and second peak to average ratios against the first and second durations; selecting a dimensioning interval duration based on the determined goodness of fit value; and estimating a capacity of the link based on the selected dimensioning interval duration. determining, for a first set of traffic observations, wherein the first set includes a first series of traffic observations each indicating the amount of traffic on a link within an observation interval of a first duration, a peak value of a traffic observation of the first series of traffic observations and an average value of the first series of traffic observations; calculating a first peak to average ratio for the first set of traffic observations based on the determined peak and average values for the first set of traffic observations; the method characterised by: determining, for a second set of traffic observations, wherein the second set includes a second series of traffic observations each indicating the amount of traffic on the link within an observation interval of a second duration, a peak value of a traffic observation of the second series of traffic observations and an average value of the second series of traffic observations; calculating a second peak to average ratio for the second set of traffic observations based on the determined peak and average values for the second set of traffic observations; determining a goodness of fit value for a power function of the first and second peak to average ratios against the first and second durations; selecting a dimensioning interval duration based on the determined goodness of fit value; and estimating a capacity of the link based on the selected dimensioning interval duration. determining, for a second set of traffic observations, wherein the second set includes a second series of traffic observations each indicating the amount of traffic on the link within an observation interval of a second duration, a peak value of a traffic observation of the second series of traffic observations and an average value of the second series of traffic observations; calculating a second peak to average ratio for the second set of traffic observations based on the determined peak and average values for the second set of traffic observations; determining a goodness of fit value for a power function of the first and second peak to average ratios against the first and second durations; selecting a dimensioning interval duration based on the determined goodness of fit value; and estimating a capacity of the link based on the selected dimensioning interval duration.