In this paper we present detailed and compact GSPN models for the performance analysis, design, and planning of cellular mobile telephony networks in which the utilization of two separate frequency bands for the provision of services to end users (like in dual-band GSM systems) complicates the cellular structure with the presence of microcells and macrocells.The flexibility of the GSPN modeling approach allows a simple construction of detailed and compact models under different assumptions as regards system parameters and resource management algorithms. This makes the performance analysis of the considered type of communication systems much simpler than with direct Markovian models, and is instrumental for careful network design and planning procedures.The presentation of numerical results derived from the GSPN models proves the viability of the proposed approach, and in a particular case allows the identification of possible system shortcomings and of their countermeasures.