Dell Force10 E1200i FTOS Version 8.4.1.5 Configuration Guide for ExaScale - Page 610

www.dell.com | support.dell.com MSDP with Anycast RP Anycast RP use MSDP with PIM-SM to allow more than one active group to RP mapping. PIM-SM allows only active group to RP mapping, which has several implications: • traffic concentration: PIM-SM allows only one active group to RP mapping which means that all traffic for the group must, at least initially, travel over the same part of the network. You can load balance source registration between multiple RPs by strategically mapping groups to RPs, but this technique is less effective as traffic increases because preemptive load balancing requires prior knowledge of traffic distributions. • lack of scalable register decasulation: With only a single RP per group, all joins are sent to that RP regardless of the topological distance between the RP, sources, and receivers, and data is transmitted to the RP until the SPT switch threshold is reached. • slow convergence when an active RP fails: When multiple RPs are configured, there can be considerable convergence delay involved in switching to the backup RP. Anycast RP relieves these limitations by allowing multiple RPs per group, which can be distributed in a topologically significant manner according to the locations of the sources and receivers. 1. All the RPs serving a given group are configured with an identical anycast address. 2. Sources then register with the topologically closest RP. 3. RPs use MSDP to peer with each other using a unique address. Figure 31-8. MSDP with Anycast RP AS X Area 0 (10.11.4.2, 239.0.0.1), uptime 00:00:52, expires 00:03:20, flags: FTA Incoming interface: GigabitEthernet 2/1, RPF neighbor 0.0.0.0 Outgoing interface list: GigabitEthernet 2/11 Forward/Sparse 00:00:50/00:02:40 GigabitEthernet 2/31 Forward/Sparse 00:00:50/00:02:40 PC 2 Source + IGMP PC 3 Receiver OSPF + PI OSPF + PIM + IGMP M 2/1 R2 2/11 BGP RP2 4/1 4/31 3/21 R3 3/41 AS Y R4 Area 0 (*, 239.0.0.1), uptime 00:00:23, expires 00:00:00, RP 192.168.0.3, flags: SCJ Incoming interface: GigabitEthernet 4/31, RPF neighbor 10.11.6.34 Outgoing interface list: GigabitEthernet 4/1 Forward/Sparse 00:00:23/Never (10.11.4.2, 239.0.0.1), uptime 00:00:23, expires 00:03:18, flags: CT Incoming interface: GigabitEthernet 4/31, RPF neighbor 10.11.6.34 Outgoing interface list: GigabitEthernet 4/1 Forward/Sparse 00:00:23/Never 1/21 1/2 MSDP Peership R1 RP1 1/1 (*, 239.0.0.1), uptime 00:00:09, expires 00:00:00, RP 192.168.0.1, flags: SCJ Incoming interface: Null, RPF neighbor 0.0.0.0 Outgoing interface list: GigabitEthernet 1/1 Forward/Sparse 00:00:09/Never PC 1 Receiver (10.11.4.2, 239.0.0.1), uptime 00:00:05, expires 00:03:25, flags: CTM Incoming interface: GigabitEthernet 1/21, RPF neighbor 10.11.1.21 Outgoing interface list: GigabitEthernet 1/1 Forward/Sparse 00:00:09/Never RP3 (*, 239.0.0.1), uptime 00:00:14, expires 00:03:16, RP 192.168.0.3, flags: S Incoming interface: Null, RPF neighbor 0.0.0.0 Outgoing interface list: GigabitEthernet 3/41 Forward/Sparse 00:00:14/00:03:16 (10.11.4.2, 239.0.0.1), uptime 00:00:14, expires 00:03:17, flags: TM Incoming interface: GigabitEthernet 3/21, RPF neighbor 10.11.0.23 Outgoing interface list: GigabitEthernet 3/41 Forward/Sparse 00:00:14/00:03:16 610 | Multicast Source Discovery Protocol