This paper proposes a new connectivity-preserving protocol in terms of rectangle-like regions. The protocol consists of a set of distributed control rules; their working together guarantees the network connectivity as well as rendezvous of a discrete-time multi-agent system. It is assumed that all agents share a common minimum sensing radius, but the information exchange may suffer from link failure and recovery. Consequently, the interaction topology is in fact directed and time-varying. By rigorous mathematical arguments, we show the effectiveness and robustness of the protocol in the presence of alignment errors in local coordinate orientations of agents and measurement errors in relative positions of neighbors. We also present simulations to demonstrate the effectiveness of the theoretical results. (C) 2011 Elsevier Ltd. All rights reserved.