Dynamic precedence for military IP networks

Current IP routed networks can support a wide range of real-time, non-real-time applications through the use of various quality of service (QoS) and class of service (CoS) methodologies. What's missing in these commercial solutions is a precedence scheme which minimizes the probability of mission-critical calls and data streams being rejected or negatively affected by "background traffic". Such a capability exists in military voice switches in the form of multi-level precedence and preemption (MLPP). In the bandwidth limited tactical environment, a preemptive network service that discriminates among traffic flows based on their importance (precedence) is essential to meeting mission requirements. This paper presents a hierarchical questing and scheduling algorithm which provides preemptive precedence between traffic flows of varying importance, and which also supports classes of service for flows with differing service requirements (e.g., real-time voice, non real-time data). At the top of the hierarchy we use a strict, preemptive, scheduler to distinguish between precedence levels and guarantee that the maximum bandwidth is made available to mission critical traffic. Subordinate to the preemptive scheduler we have implemented a variant of weighted fair queueing which assures that the bandwidth available to each precedence level is distributed among the service classes according to current policy.