Protocol Independent Multicast-Sparse Mode (PIM-SM): Implementation Document
Ahmed Helmy · 1997
This document describes the details of the PIM-SM [1, 2, 3] version 2 implementation for UNIX platforms; namely SunOS and SGI-IRIX. A generic kernel model is adopted, which is protocol independent, however some supporting functions are added to the kernel for encapsulation of data packets at user level and decapsulation of PIM Registers. Further, the basic model for the user level, PIM daemon (pimd), implementation is described. Implementation details and code are included in supplementary appendices. 1 Introduction In order to support multicast routing protocols in a UNIX environment, both the kernel and the daemon parts have to interact and cooperate in performing the processing and forwarding functions. The kernel basically handles forwarding the data packets according to a multicast forwarding cache (MFC) stored in the kernel. While the protocol specific daemon is responsible for processing the control messages from other routers and from the kernel, and maintaining the multicast ...