Brocade Communications Dell Ericsson Verizon Telefonica This draft discusses two use cases to help identify the requirements for policy-based routing in I2RS. Both of the use cases involve identification of certain flows and then using I2RS to program routers with special handling for those flows. The first use case deals with improving bandwidth efficiency. Demands on networking bandwidth are growing exponentially due to applications such as large file transfers and those with rich media. Link Aggregation Group (LAG) and Equal Cost Multipath (ECMP) are extensively deployed in networks to scale the bandwidth. However, the static hash-based load balancing techniques used today make inefficient use of the bandwidth in the presence of long-lived large flows. We discuss how I2RS can be used for achieving better load balancing. The second use case is for recognizing and mitigating Layer 3-4 based DDoS attacks. Behavioral security threats such as Distributed Denial of Service (DDoS) attacks are an ongoing problem in today's networks. DDoS attacks can be Layer 3-4 based or Layer 7 based. We discuss how such attacks can be recognized and how I2RS can be used for mitigating their effects.