Demo 4.4 - PIM Sparse Mode on Junos Routers Part 2

In this CCIE and JNCIE IP Multicast demo we cover PIM Sparse Mode on Junos routers in detail, using detailed packet captures. Please download the topology file from https://www.dropbox.com/sh/124zmocrwp... to follow along with the videos. The scenarios covered include: IGMP signaling Multicast Receivers present initially, followed by Multicast Sources appearing (PIM Sparse Mode (*,G) Joins for the Rendezvous Point Tree (RPT) terminating at the RP (Rendezvous Point) followed by the PIM Registration process by an FHR Source signaling by the Multicast Source (MC message reception by the FHR) first, followed by IGMP Multicast Receivers appearing on the LHR (FHR and the RP communicating via the PIM Sparse Mode (PIM-SM) Register message followed by LHR and RP communication via PIM Sparse Mode (*,G) Joins) Each scenario repeated with SPT Switchover taking place on first packet PIM Sparse-Mode topics relevant to CCIE and JNCIE candidates include: The actions carried out by the RP in reaction to an (S,G) message received for an active (*,G) group without SPT switchover -- RP decapsulates the multicast packet out of the PIM Register message -- RP sends the packet down the (*,G) tree -- RP starts the (S,G) PIM Join process towards the FHR -- FHR will send the next packets both in a PIM Register message and natively down the -- RP sets the SPTbit on reception of a multicast packet over the (S,G) tree and generates a Register-Stop towards the FHR The actions carried out by the RP in reaction to a (*,G) message received for an active (S,G) group in Register state without SPT switchover -- RP will initiate an (S,G) Join towards the FHR -- As the RP receives the packets over the (S,G) tree, its sets the SPTbit on the state and relays the packets down the (*,G) tree -- As an optimization, the RP also copies the OIL of the (*,G) state to the (S,G) state and packet counters are incremented only on the (S,G) state -- Downstream router still only keeps the (*,G) state and packet counters are incremented only on the (S,G) state Both of the scenarios with Shortest Path Tree Switchover (SPT Switchover) occurring on first packet -- LHR will create an (S,G) entry on reception of the first Multicast packet and set the SPTbit -- All routers will process both the (S,G) and the (*,G) Joins -- The first middle hop router to notice a difference in the RPF interfaces for (S,G) and (*,G) will initiate the (S,G,RPT) Prune towards the RP -- The RP (Rendezvous Point) will send and (S,G) Prune in reaction to the (S,G,RPT) Prune