This paper presents the design and evaluation through a discrete event simulation of an ODP-based Adaptive Computing Architecture which manages network resources in large-scale heterogeneous error-prone networks. The emphasis is given to network (communication) adaptation of this architecture. The architecture is simulated for an exemplar defense network. The results show that, for this network, the architecture provides significant improvement in terms of higher priority requests meeting their QoS requirements and adaptation to link failure under heavy link utilization. In addition, link utilization is lower with the architecture active.