Policy tree multicast routing: an extension to sparse mode source tree delivery

Bandwidth-sensitive multicast delivery controlled by routing criteria pertinent to the actual traffic flow is very costly in terms of router state and control overhead and it scales poorly towards larger, wide-area networks. PIM-SM (Protocol-independent Multicast - Sparse Mode) has been introduced as a simple, flexible and scalable concept for Internet-wide multicasting. Yet, PIM's efficiency potential (like that of alternative wide-area multicast concepts) can only be fully exploited if it is based on Reverse Path Forwarding (RPF), a low-cost mechanism, which however does not select prescribed delivery paths if link parameters or routing policies are asymmetric. This paper presents an extension to protocols like PIM-SM, called Policy Tree Multicast Routing (PTMR). This concept leads to multicast delivery trees which, even under asymmetric conditions, readily comply with imposed macroscopic policies and moreover enable support of shortest path and QoS criteria. PTMR gives no cons...

• Type: Journal
• Year: 1998
• Where: CCR
• Authors: Horst Hodel
• Keywords: CCR 1998, Multicast, PIM-SM, Wide-area Multicast Concepts