Technical Tip: Multicast PIM sparse limitation and implementation in VRF

In v7.x, v7.2.x, and 7.4.x, multicast PIM sparse is only supported in the default VRF or VRF 0. If PIM is implemented in another VRF on this version, it will not work, as shown in the logs below:

PIM-SM: PIM Bootstrap packet Recved.

PIM-SM: PIM Bootstrap from x.x.x.x

PIM-SM: Bootstrap message

PIM-SM: Fragment Tag: 4512

PIM-SM: Hash masklen: 32

PIM-SM: BSR priority: 155

PIM-SM: BSR: x.x.x.x (Family 1, Type 0)

PIM-SM: Nexthop for x.x.x.x unreachable

PIM-SM: Nexthop for x.x.x.x unreachable

PIM-SM: Nexthop for x.x.x.x unreachable

PIM-SM: MRIB.next_hop_rp(x.x.x.x): Can't find nexthop

PIM-SM: RPF_neighbor(BSM.BSR_ip_address) lookup failed

PIM-SM: PIM Bootstrap message is ignored by BSM process check

Useful commands:

diagnose ip multicast mroute
diagnose sys mcast-session list
diagnose ip multicast npu-session list

V7.6.1 includes a new feature to implement the PIM sparse in multiple VRFs. It can be configured by following the steps in Enhanced PIM support for VRFs—FortiOS 7.6.0 new features