RFC 3170 (rfc3170) - Page 2 of 28

IP Multicast Applications: Challenges and Solutions

RFC 3170               IP Multicast Applications          September 2001


     4.2 Delay Requirements . . . . . . . . . . . . . . . . . . . . .13
   5. Unique Multicast Service Requirements . . . . . . . . . . . . .14
     5.1 Address Management . . . . . . . . . . . . . . . . . . . . .16
     5.2 Session Management . . . . . . . . . . . . . . . . . . . . .16
     5.3 Heterogeneous Receiver Support . . . . . . . . . . . . . . .18
     5.4 Reliable Data Delivery . . . . . . . . . . . . . . . . . . .20
     5.5 Security . . . . . . . . . . . . . . . . . . . . . . . . . .21
     5.6 Synchronized Play-Out. . . . . . . . . . . . . . . . . . . .23
   6. Service APIs. . . . . . . . . . . . . . . . . . . . . . . . . .23
   7. Security Considerations . . . . . . . . . . . . . . . . . . . .24
   8. Acknowledgements. . . . . . . . . . . . . . . . . . . . . . . .24
   9. References. . . . . . . . . . . . . . . . . . . . . . . . . . .24
   10. Authors' Addresses . . . . . . . . . . . . . . . . . . . . . .27
   11. Full Copyright Statement . . . . . . . . . . . . . . . . . . .28

1. Introduction

   IP Multicast will play a prominent role on the Internet in the coming
   years.  It is a requirement, not an option, if the Internet is going
   to scale.  Multicast allows application developers to add more
   functionality without significantly impacting the network.

   Developing multicast-enabled applications is ostensibly simple.
   Having datagram access allows any application to send to a multicast
   address.  A multicast application need only increase the Internet
   Protocol (IP) time-to-live (TTL) value to more than 1 (the default
   value) to allow outgoing datagrams to traverse routers.  To receive a
   multicast datagram, applications join the multicast group, which
   transparently generates an [IGMPv2, IGMPv3] group membership report.

   This apparent simplicity is deceptive, however.  Enabling multicast
   support in applications and protocols that can scale well on a
   heterogeneous network is a significant challenge.  Specifically,
   sending constant bit rate datastreams, reliable data delivery,
   security, and managing many-to-many communications all require
   special consideration.  Some solutions are available, but many of
   these services are still active research areas.

1.1 Motivation

   The purpose of this document is to provide a framework for
   understanding the challenges of designing and implementing multicast
   applications.  In order to use multicast communications correctly,
   application developers must first understand the various I/O models
   and the network services (in addition to basic multicast
   communication) that are required.  Secondly, application developers





Quinn, et al.                Informational