Due to the autonomous nature of ISPs, the service level agreement (SLA) offering is currently confined to within a single provider network. In this work, we examine some methods of extending the SLA offering across ISP boundaries. We introduce three policies to coordinate the end-to-end performance guarantee in multiple ISP networks: the least-effort, the most-effort, and the equal-distribution policies. These policies refer to different manners in which the service-level constraints are distributed among all transit networks. We study the impacts of these policies on the overall ISP community when SLA is required. We evaluate the effectiveness of these policies in terms of both the network performance and the ISP's monetary profit. The results show that the policy choice depends on the network load, as well as the ISP cost structure.