© 2006 Cisco Systems, Inc. All rights reserved. BSCI v Implementing Multicast Explaining Multicast Routing Protocols

© 2006 Cisco Systems, Inc. All rights reserved. BSCI v Multicast Protocol Basics Types of multicast distribution trees Source-rooted; also called shortest path trees (SPTs) Rooted at a meeting point in the network; shared trees –Rendezvous point (RP) –Core Types of multicast protocols Dense mode protocols Sparse mode protocols

© 2006 Cisco Systems, Inc. All rights reserved. BSCI v Shortest-Path Trees Shortest-Path or Source Distribution Tree

© 2006 Cisco Systems, Inc. All rights reserved. BSCI v Shortest-Path Trees (Cont.) Shortest-Path or Source Distribution Tree

© 2006 Cisco Systems, Inc. All rights reserved. BSCI v Shared Distribution Trees Shared Distribution Tree

© 2006 Cisco Systems, Inc. All rights reserved. BSCI v Shared Distribution Trees (Cont.) Shared Distribution Tree

© 2006 Cisco Systems, Inc. All rights reserved. BSCI v Multicast Distribution Trees Identification (S,G) entries For this particular source sending to this particular group Traffic forwarded via the shortest path from the source (*,G) entries For any (*) source sending to this group Traffic forwarded via a meeting point for this group

© 2006 Cisco Systems, Inc. All rights reserved. BSCI v Multicast Forwarding Multicast routing operation is the opposite of unicast routing. Unicast routing is concerned with where the packet is going. Multicast routing is concerned with where the packet comes from. Multicast routing uses Reverse Path Forwarding to prevent forwarding loops.

© 2006 Cisco Systems, Inc. All rights reserved. BSCI v PIM-DM Flood and Prune Initial Flooding

© 2006 Cisco Systems, Inc. All rights reserved. BSCI v PIM-DM Flood and Prune (Cont.)

© 2006 Cisco Systems, Inc. All rights reserved. BSCI v PIM-DM Flood and Prune (Cont.) Results After Pruning

© 2006 Cisco Systems, Inc. All rights reserved. BSCI v PIM Sparse Mode Protocol independent: works with any of the underlying unicast routing protocols Supports both source and shared trees Based on an explicit pull model Uses an RP –Senders and receivers meet each other. Senders are registered with RP by their first-hop router. Receivers are joined to the shared tree (rooted at the RP) by their local DR.

© 2006 Cisco Systems, Inc. All rights reserved. BSCI v PIM-SM Shared Tree Join

© 2006 Cisco Systems, Inc. All rights reserved. BSCI v Multiple RPs with Auto RP Shared Distribution Tree

© 2006 Cisco Systems, Inc. All rights reserved. BSCI v Summary IP multicast requires multiple protocols and processes for proper packet forwarding. Source and shared trees may be used to define multicast packet flows to group members. Multicast routing utilizes the distribution trees for proper packet forwarding. PIM is the routing protocol for multicast. PIM-DM uses flood and prune. PIM-SM uses less device and bandwidth resources and is typically chosen to implement multicast. PIM sparse-dense mode is the recommended methodology for maximum efficiency in IP multicast.

© 2006 Cisco Systems, Inc. All rights reserved. BSCI v