Configuring Basic IPv4 PIM-DM Functions

Pre-configuration Tasks

Before configuring basic PIM-DM functions, configure a unicast routing protocol to ensure normal unicast routing on the network. Because multicast devices do not maintain unicast routing information independently on the network, the devices must perform the RPF check on the received packets according to the unicast routing information on the network before creating PIM routing entries.

Context

PIM-DM and PIM-SM cannot be enabled simultaneously in the public network instance or VPN instances. Since PIM Hello packets do not carry messages in PIM mode, a PIM switch cannot know the mode of the PIM protocol that its PIM neighbor runs. If the RPF interface and the RPF neighbor run PIM protocols of different modes, two neighboring devices cannot learn PIM routing information from each other. As a result, related multicast forwarding entries cannot be correctly created.

It is recommended that you enable PIM-DM on all interfaces on a PIM-DM network, so that the interfaces can establish neighbor relationships with all connected PIM devices.

If PIM-DM and Internet Group Management Protocol (IGMP) need to be enabled on the same interface, enable PIM-DM before IGMP.

Procedure

Enable PIM-DM for a public network instance.
1. Run system-view
  The system view is displayed.
2. Run multicast routing-enable
  IP multicast routing is enabled.
3. Run interface interface-type interface-number
  The interface view is displayed.
4. (Optional) On an Ethernet interface, run undo portswitch
  The interface is switched to Layer 3 mode.
  
  By default, an Ethernet interface works in Layer 2 mode.
  
  Only the S5720-EI, S5720-HI, S5730-HI, S5731-H, S5731-S, S5731S-H, S5731S-S, S5732-H, S6720-EI, S6720-HI, S6720S-EI, S6730-H, S6730S-H, S6730-S, and S6730S-S support switching between Layer 2 and Layer 3 modes.
5. Run pim dm
  PIM-DM is enabled.
Enable PIM-DM for a VPN instance.
A VPN instance must exist before you enable PIM-DM in it.
1. Run system-view
  The system view is displayed.
2. Run ip vpn-instance vpn-instance-name
  The VPN instance view is displayed.
3. Run ipv4-family
  The IPv4 address family is enabled for the VPN instance, and the VPN instance IPv4 address family view is displayed.
4. Run route-distinguisher route-distinguisher
  An RD is configured for the VPN instance IPv4 address family.
5. Run multicast routing-enable
  IP multicast routing is enabled.
6. Run quit
  Return to the VPN instance view.
7. Run quit
  Return to the system view.
8. Run interface interface-type interface-number
  The interface view is displayed.
9. Run ip binding vpn-instance vpn-instance-name
  The interface is associated with a specified VPN instance.
10. Run pim dm
  PIM-DM is enabled.

Verifying the Configuration

After PIM-DM is enabled on all the interfaces in a PIM domain, use the following commands to check information about PIM interfaces, PIM neighbors, and PIM routing entries.

Run the display pim interface [ interface-type interface-number | up | down ] [ verbose ] command to check PIM information on an interface.
Run the display pim neighbor [ neighbor-address | interface interface-type interface-number | verbose ] ^* command to check information about PIM neighbors.
Run the following commands to check the PIM routing table:
- Run the display pim routing-table [ group-address [ mask { group-mask-length | group-mask } ] | source-address [ mask { source-mask-length | source-mask } ] | incoming-interface { interface-type interface-number | register } | outgoing-interface { include | exclude | match } { interface-type interface-number | register | none } | mode { dm | sm | ssm } | flags flag-value | fsm ] ^* [ outgoing-interface-number [ number ] ] command to check detailed information about the PIM routing table.
- Run the display pim routing-table brief [ group-address [ mask { group-mask-length | group-mask } ] | source-address [ mask { source-mask-length | source-mask } ] | incoming-interface { interface-type interface-number | register } ] ^* command to check brief information about the PIM routing table.