A Tiered Model for Cross-Domain QoS Delivery

The Department of Defense (DoD) has immediate and critical need for differentiated services for voice, video and data with the plannedphase out of Defense Information System Agency (DISA) Asynchronous Transfer Mode (ATM) service. The DoD requirements are unique, they comprise highly granular precedence requirements in addition to exacting service differentiation. This is an immensely complex environment given that hundreds of heterogeneous network domains and mixed data flows exist in the Global Information Grid (GIG). This paper examines a practical, scalable, prioritized delivery model that comprises a two-tier concept for differentiated services. It provides rationale for not using dynamic, signaled resource reservation mechanism for guaranteeing services. In the proposed model, all GIG traffic is classified into two basic priority categories, first, the high-priority traffic, this cannot be subject to any Quality of Service (QoS) mechanism that will hinder its prioritized delivery across the network and second, all other traffic, this latter traffic can be subject to QoS mechanisms for service differentiation and resulting delivery. Finally, it is noted that the findings of this analysis may have implications for the design of networks on the Internet at large.