IP Multicast 29 4 29 4.1 Reverse Path Forwarding ....... 4.2 Internet Group Management Protocol 31 Truncated Broadcasting ........ 32 4.3 4.4 Distance Vector Multicast Routing Protocol (DVMRP) 34 4.5 Summary · ......................... 35 5 Multicast Extensions to Open Shortest Path First (MO- SPF) 39 5.1 High-level Description 39 Architecture ...... 40 5.2 5.2.1 Design Goals 41 Protocol Data Structures 41 5.2.2 5.3 Protocol. 44 52 5.4 Summary · ............ 6 Protocol Independent Multicast (PIM) 53 6.1 High-Level Description 53 54 6.2 Architecture . . . . . . . . . . . . . 6.2.1 Design Goals: ........ 54 6.2.2 Components and Functions 55 6.3 Protocol ............... 57 6.3.1 Creating the PIM framework 58 6.3.2 Creating a specific multicast tree for a group 59 6.3.3 Multicast data forwarding . . . . . . 64 6.3.4 Operation in a multi-access network 65 6.3.5 List of PIM messages 68 6.3.6 A complete example 69 6.4 Summary · ...... 69 7 Core-Based Tree (CBT) 73 7.1 High-level Description 73 7.2 Architecture . . . . . . 74 7.2.1 Design Goals: .