Bandwidth in the Internet is constantly increasing. The last mile problem of the Internet has almost been solved. Multimedia has emerged as a dominant type of traffic on the Internet. Multicast is increasingly seen as the delivery vehicle of choice for multimedia streams. What has been the one true stumbling roadblock in widespread use of multicast is the lack of a convenient mechanism for multicast session discovery. This paper examines existing techniques that try to address this issue, highlighting the benefits and drawbacks of such schemes. It then proposes our hierarchical and globally scalable session directory architecture. An analysis of benefits and drawbacks of our scheme follows. The paper concludes with arguments why our scheme might be generally more suitable for global deployment, which may allow end users to enjoy the true power and efficiency of IP multicast.