SUMMARYIn gigabit passive optical networks (GPONs), the ports of the optical line terminal (OLT) support passive optical networks (PONs). An optical split ratio supported on an OLT chassis determines the number of optical network units (ONUs) which can share PON link capacity. Generally, network planners tend to do dimensioning for PON link capacity (OLT port) based on the number of subscribers and their type (i.e. residential or business). Although this dimensioning approach is simple, it does not guarantee a selection of optical split ratio which can optimally allocate bandwidth to end‐subscribers. In this paper, we develop an integrated mathematical framework for optimally dimensioning resources in an GPON access network, namely OLT capacity. This framework comprises three resource‐dimensioning approaches which are based on user requirements: GPON link utilization and capacity optimization. Our mathematical framework has been integrated into software for GPON resource dimensioning, which we have developed to evaluate the support and performance of services in GPON access networks. Copyright © 2011 John Wiley & Sons, Ltd.