A computer-implemented system and method are described for exchanging messages between nodes and servers in accordance with specified service level guarantees, while at the same time retaining compatibility with other nodes and servers not subject to the same service level guarantees. For example, a system according to one embodiment of the invention comprises: a first cluster of servers having messaging applications executed thereon for enabling message passing between a first plurality of nodes, a first message database maintained by the first cluster of servers for storing an archive of messages passed between the first plurality of nodes; a second cluster of servers having the same messaging applications executed thereon for enabling message passing between a second plurality of nodes; and a second message database maintained by the second cluster of servers for storing an archive of messages passed between the second plurality of nodes; wherein the first cluster of servers implement a first set of protocols for ensuring latency and/or data retention requirements above a first specified threshold when exchanging messages between the first plurality of nodes. The first set of protocols may ensure various other characteristics of communication including, by way of example and not limitation, message delivery receipts and guaranteed call quality for voice calls.