A multicast distribution tree cannot be correctly built

Symptom

No multicast forwarding entries are established on the devices (including devices directly connected with multicast sources or receivers) in a PIM network. This means that a multicast distribution tree cannot be built correctly.

Solution

To resolve the problem:

  1. Use display ip routing-table to verify that a unicast route to the multicast source or the RP is available.

  2. Use display pim interface to verify PIM information on each interface, especially on the RPF interface. If PIM is not enabled on the interfaces, use pim dm or pim sm to enable PIM-DM or PIM-SM for the interfaces.

  3. Use display pim neighbor to verify that the RPF neighbor is a PIM neighbor.

  4. Verify that PIM and IGMP are enabled on the interfaces that directly connect to the multicast sources or the receivers.

  5. Use display pim interface verbose to verify that the same PIM mode is enabled on the RPF interface on a device and the connected interface of the device's RPF neighbor.

  6. Use display current-configuration to verify that the same PIM mode is enabled on all devices. For PIM-SM, verify that the BSR and C-RPs are correctly configured.

  7. If the problem persists, contact Hewlett Packard Enterprise Support.