Asynchronous feedback of network capacity for application layer tuning

The traditional layered network architecture limits the amount of information which is passed between layers of the protocol stack. When data is passed in such a network, it is in the form of a protocol message sent via a service access point (SAP). Because of layer and service access limitations, metrics about network conditions are difficult to pass across multiple layers of the protocol stack. Using this traditional network architecture in high demand, low bandwidth networks can lead to unresolved growth in message latency and subsequent network collapse. This paper presents an asynchronous mechanism that allows various layers of a protocol stack to make informed decisions on the data to be sent based on the current and predicted network performance characteristics. By asynchronous, we mean that intervening layers of the protocol stack are not invoked to pass a message along to the application layer; instead, an external communications mechanism is used to store and hold these metrics. We show how access to data link layer information, such as channel access times, can allow us to tune the application layer performance to more efficiently utilize the available network capacity and prevent network failure. In bandwidth-limited military networks, this efficient use of the physical media, is crucial to winning the information war.