Example for Configuring Multicast Static Routes to Connect RPF Routes

After multicast static routes are configured, a receiver can receive multicast data from a multicast source in another area that is unreachable with unicast routes.

Networking Requirements

As shown in Figure 1, the network runs PIM-SM, all routers support multicast, and the receiver can receive information from Source1. Device B and Device C run OSPF. There is no unicast route between Device A and Device B. To enable the receiver to receive information sent from Source 2, configure a multicast static route.

Figure 1 Configuring multicast static routes to connect RPF routes

Device Name	Interface	IP Address
DeviceA	GE0/1/0	10.1.5.1/24
DeviceA	GE0/1/16	10.1.4.2/24
DeviceB	GE0/1/0	10.1.2.2/24
	GE0/1/8	10.1.3.1/24
	GE0/1/16	10.1.4.1/24
DeviceC	GE0/1/0	10.1.2.1/24
DeviceC	GE0/1/8	10.1.1.1/24

Precautions

When configuring multicast static routes to connect RPF routes, note the following precautions:

PIM-SM must be enabled before IGMP is enabled.
When configuring a multicast static route, if the next hop is a Point-to-point (P2P) interface, you must specify the outbound interface number; if the next hop is not a P2P interface, you must specify the next-hop address.

Configuration Roadmap

The configuration roadmap is as follows:

Configure an IP address for each router interface and configure OSPF on routers.
Enable multicast routing on each router, enable PIM-SM on each interface, and enable IGMP on interfaces connecting routers to hosts.
Configure candidate-bootstrap routers (C-BSRs) and candidate-rendezvous points (C-RPs).
Configure multicast static routes on Device B and Device C.

Data Preparation

To complete the configuration, you need the following data:

IP address of Source 2
RPF interface connecting Device B to Source 2 and the RPF neighbor of Device B
RPF interface connecting Device C to Source 2 and the RPF neighbor of Device C

Procedure

Configure an IP address for each router interface and a unicast routing protocol. For configuration details, see Configuration Files in this section.

Enable multicast routing on each router and PIM-SM on each router interface.

# Configure Device B. The configurations of Device A and Device C are similar to the configuration of Device B. For configuration details, see Configuration Files in this section.

[~DeviceB] multicast routing-enable
[*DeviceB] interface GigabitEthernet 0/1/0
[*DeviceB-GigabitEthernet0/1/0] pim sm
[*DeviceB-GigabitEthernet0/1/0] quit
[*DeviceB] interface gigabitethernet 0/1/8
[*DeviceB-GigabitEthernet0/1/8] pim sm
[*DeviceB-GigabitEthernet0/1/8] quit
[*DeviceB] interface GigabitEthernet 0/1/16
[*DeviceB-GigabitEthernet0/1/16] pim sm
[*DeviceB-GigabitEthernet0/1/16] commit
[~DeviceB-GigabitEthernet0/1/16] quit

Enable IGMP on interfaces that connect to hosts.

# Enable IGMP on the interface connecting Device C to hosts.

[~DeviceC] interface gigabitethernet 0/1/8
[~DeviceC-GigabitEthernet0/1/8] igmp enable
[*DeviceC-GigabitEthernet0/1/8] commit
[~DeviceC-GigabitEthernet0/1/8] quit

Configure C-BSRs and C-RPs.
# Configure GE 0/1/0 on Device B as both a C-BSR and a C-RP.
```
[~DeviceB] pim
[*DeviceB] c-bsr GigabitEthernet 0/1/0
[*DeviceB] c-rp GigabitEthernet 0/1/0
[*DeviceB] commit
[~DeviceB] quit
```
Source 1 (10.1.3.2/24) and Source2 (10.1.5.2/24) both send multicast data to G (225.1.1.1). The receiver joins G and can receive multicast data sent from Source 1 and Source 2.

# Run the display multicast rpf-info 10.1.5.2 command on Device B and Device C. There is no command output. This indicates that Devices have no RPF routes to Source 2.

Configure multicast static routes.

# Configure a multicast static route on Device B and specify Device A as an RPF neighbor to Source 2.

<DeviceB> system-view
[~DeviceB] ip rpf-route-static 10.1.5.0 255.255.255.0 10.1.4.2
[*DeviceB] commit
[~DeviceB] quit

# Configure a multicast static route on Device C and specify Device B as an RPF neighbor to Source2.

<DeviceC> system-view
[~DeviceC] ip rpf-route-static 10.1.5.0 255.255.255.0 10.1.2.2
[*DeviceC] commit
[~DeviceC] quit

Verify the configuration.

# Run the display multicast rpf-info 10.1.5.2 command again on Device B and Device C. The command output shows RPF information of Source 2.

<DeviceB> display multicast rpf-info 10.1.5.2
VPN-Instance: public net
RPF information about: 10.1.5.2
     RPF interface: GigabitEthernet0/1/16, RPF neighbor: 10.1.4.2
     Referenced route/mask: 10.1.5.0/24
     Referenced route type: mstatic
     Route selecting rule: preference-preferred
     Load splitting rule: disable 
<DeviceC> display multicast rpf-info 10.1.5.2
VPN-Instance: public net
RPF information about source 10.1.5.2:
     RPF interface: GigabitEthernet0/1/0, RPF neighbor: 10.1.2.2
     Referenced route/mask: 10.1.5.0/24
     Referenced route type: mstatic
     Route selection rule: preference-preferred
     Load splitting rule: disable

# Run the display pim routing-table command on Device C to view information about PIM routing tables. Device C has multicast entries related to Source 2 and the receiver can receive multicast data from Source 2.

<DeviceC> display pim routing-table
VPN-Instance: public net
 Total 1 (*, G) entry; 2 (S, G) entries
 (*, 225.1.1.1)
     RP: 10.1.2.2
     Protocol: PIM-SM, Flag: WC
     UpTime: 03:54:19
     Upstream interface: NULL, Refresh time: 03:54:19
         Upstream neighbor: NULL
         RPF prime neighbor: NULL
     Downstream interface(s) information:
     Total number of downstreams: 1
         1: GigabitEthernet0/1/8
             Protocol: PIM-SM, UpTime: 01:38:19, Expires: never
(10.1.3.2, 225.1.1.1)     
     RP: 10.1.2.2
     Protocol: PIM-SM, Flag: ACT
     UpTime: 00:00:44
     Upstream interface: GigabitEthernet0/1/0, Refresh time: 00:00:44
         Upstream neighbor: 10.1.2.2
         RPF prime neighbor: 10.1.2.2
     Downstream interface(s) information:
     Total number of downstreams: 1
          1: GigabitEthernet0/1/8
              Protocol: PIM-SM, UpTime: 00:00:44, Expires: never
(10.1.5.2, 225.1.1.1)     
     RP: 10.1.2.2
     Protocol: PIM-SM, Flag: ACT
     UpTime: 00:00:44
     Upstream interface: GigabitEthernet0/1/0, Refresh time: 00:00:44
         Upstream neighbor: 10.1.2.2
         RPF prime neighbor: 10.1.2.2
     Downstream interface(s) information:
     Total number of downstreams: 1
          1: GigabitEthernet0/1/8
              Protocol: PIM-SM, UpTime: 00:00:44, Expires: never

Configuration Files

Device A configuration file

#
sysname DeviceA
#
multicast routing-enable
#
interface GigabitEthernet0/1/0
 undo shutdown
 ip address 10.1.5.1 255.255.255.0
 pim sm
#
interface GigabitEthernet0/1/16
 undo shutdown
 ip address 10.1.4.2 255.255.255.0
 pim sm
#
ospf 1
 area 0.0.0.0
  network 10.1.5.0 0.0.0.255
   network 10.1.4.0 0.0.0.255
#
return

Device B configuration file

#
sysname DeviceB
#
multicast routing-enable
#
interface GigabitEthernet0/1/0
 undo shutdown
 ip address 10.1.2.2 255.255.255.0
 pim sm
#
interface GigabitEthernet0/1/8
 undo shutdown
 ip address 10.1.3.1 255.255.255.0
 pim sm
#
interface GigabitEthernet0/1/16
 undo shutdown
 ip address 10.1.4.1 255.255.255.0
 pim sm
#
ospf 1
 area 0.0.0.0
  network 10.1.2.0 0.0.0.255
  network 10.1.3.0 0.0.0.255
#
pim
 c-bsr GigabitEthernet0/1/16
 c-rp GigabitEthernet0/1/16
#
ip rpf-route-static 10.1.5.0 24 10.1.4.2
#
return

Device C configuration file

#
sysname DeviceC
#
multicast routing-enable
#
interface GigabitEthernet0/1/8
 undo shutdown
 ip address 10.1.1.1 255.255.255.0
 pim sm
 igmp enable
#
interface GigabitEthernet0/1/16
 undo shutdown
 ip address 10.1.2.1 255.255.255.0
 pim sm
#
ospf 1
 area 0.0.0.0
  network 10.1.1.0 0.0.0.255
  network 10.1.2.0 0.0.0.255
#
ip rpf-route-static 10.1.5.0 24 10.1.2.2
#
return