A survey of dynamically adaptable protocol stacks

The continuous development of new networking standards over the last decade has resulted in an unprecedented proliferation of interfacing technologies and their associated protocol stacks. Never before was such a wide gamut of network architectures, protocol configurations and deployment options available to network designers. Alas, this significant increase in flexibility has come at the cost of an increased complexity in network management tasks, particularly with regard to the accommodation of performance requirements. Especially in mobile settings, this is due to the greater probability of unforeseen communication contexts that renders the efficient provisioning of multiple dissimilar protocol stacks a challenging task. To address this unpredictability, several approaches based on the dynamic adaptation of protocol stacks during runtime have been proposed and investigated over the years. This article surveys major research efforts dealing with the introduction of a dynamic adaptation capacity into protocol stack subsystems. To this end, we present the respective architectures with a focus on their functional entities and their particular mode of operation. Most importantly, we elaborate on the various design approaches to adaptability and the entailed degree of coupling between protocol stack-and layer-entities and their impact on resource allocation models. Furthermore, we classify these research efforts according to a taxonomy for non-monolithic protocol stacks and discuss design trade-offs inherent in each class. We conclude the article with a summary of the key design principles for adaptable protocol stack architectures.