Military communications networks must be robust, redundant and enable interoperability. The project Samverkan mellan mobila taktiska nät is a 3-year FoT-project that has investigated communication architectures that can incorporate different types of radio networks of varying sizes, and use the limited spectrum effectively. The aim has been to investigate techniques for connecting networks efficiently and enable networks to coexist within a limited frequency space. Various methods for interconnecting networks based on OLSR routing on OSI layer 3 have been studied. The overall design goal was to keep the overhead generated by OLSR control traffic down while maintaining a high packet delivery ratio. By introducing a number of changes compared to the OLSR standard, a reasonable solution is obtained. The project has also participated in the NATO Group IST-161 (COM) Efficient Group and Information Centric Communications in Mobile Military Heterogeneous Networks. Many issues within the project coincide with those of the NATO group. Co-location of networks and specifically frequency hopping SCB networks has also been studied within the project. The results showed that even for difficult interference situations, packets can be delivered in the networks with a high probability, thanks to the inherent robustness of the SCB networks. Nevertheless, SCB networks are also negatively affected due to the interferences from co-location, the delays increase and the networks can become fragmented so that some nodes cannot be reached.