Precedence and Quality of Service (QoS) Handling in IP Packet Networks

In military networks, precedence and preemption (P&P) and quality of service (QoS) are both required. QoS refers to meeting the performance requirements of an application (packet delay, packet loss, packet delay variation, service availability, connection set up time, connection acceptance ratio, etc.) while P&P refers to meeting the QoS requirements of the highest importance applications under congestion conditions, in which there are not enough network resources to satisfy the QoS requirements of all applications. In particular, preemption refers to taking away network resources from a lower precedence application in order to give the resources to a higher precedence application. Per Hob Behaviors (PHBs) are used by network nodes to implement QoS. A service level agreement (SLA) is a QoS contract that is used to assure that the QoS requirements of admitted applications are met by the network transport for defined traffic profiles. SLAs and P&P are often perceived to have an adversarial relationship. This paper proposes a way to resolve this conflict by making QoS PHBs precedence-aware, while remaining agnostic of the specific PHB mechanism