load Control Paradigm Shift Logic Resource Broker/ State Balancing Logic Persistence Service Service Logic Distribution Persistence & Monitoring Logic Converged Cloud FIGURE 14.2 Paradigm shift: architecting for SDN/NFV. Building the Network of the Future 7. A shift from stateful components with a 1+1 active/failover redundancy model to stateless/ transaction-stateful front-ends with long-lived state decoupled from logic for greater scal- ability and reliability. 8. A shift from per-network component congestion control (e.g., Session Initiation Protocol [SIP] [3] and diameter [4] overload controls) to minimizing the need for per-hop overload control by dynamically instantiating resources ahead of time using predictive traffic fore- casting. Continuous monitoring of resources identifies resource constraints before they are realized. Overload control is achieved using scale-out by dynamically instantiating components as needed. 9. A shift from a model where each element monitors the downstream elements (e.g., via SIP OPTIONS) that it sends messages to, to a model where common cloud capabilities keep track of elements and route traffic to the appropriate set of network elements to achieve uniform monitoring, routing, and management. Cloud monitoring and routing capabilities keep track of failed components and route requests to in-service compo- nents. Standard (e.g., transmission control protocol [TCP] monitoring) or VNF-specific monitoring mechanisms may be supported. 10. A shift to a model where network functions run ubiquitously across multiple cloud avail- ability regions for ease of geo-redundancy. 14.2 NEW SERVICE DESIGN SOLUTIONS WITH SDN/NFV SDN/NFV technologies open, simplify, improve the scaling of, and increase the value of networks. SDN/NFV enables a completely new paradigm for designing new solutions for services. This sec- tion describes the virtual service framework, which is a general design framework that uses SDN and NFV for rapid creation of new virtualized real-time service solutions. The framewo