Example for Configuring Multicast Static Routes to Change RPF Routes

To change the Reverse Path Forwarding (RPF) route and create a multicast path different from the source-to-receiver unicast path, configure multicast static routes on the multicast network.

Networking Requirements

As shown in Figure 1, the network runs PIM-SM, all routers support multicast, and the receiver can receive information from the multicast source. IS-IS is run between routers. Configure a multicast static route to create a multicast path from the source to the receiver different from the unicast path from the source to the receiver.

Figure 1 Configuring multicast static routes to change RPF routes

Interfaces 1 through 3 in this example represent GE 0/1/0, GE 0/1/8, and GE 0/1/16, respectively.

Precautions

When configuring multicast static routes to change 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 IS-IS 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 specify Device C as an RPF neighbor to the source.

Data Preparation

To complete the configuration, you need the following data:

IP address of the source
Outbound interface of Device B to the source

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

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

Enable IGMP on interfaces that connect to hosts.

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

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

Configure C-BSRs and C-RPs.

# Configure GE 0/1/16 on Device C as both a C-BSR and a C-RP.

[~DeviceC] pim
[*DeviceC] c-bsr GigabitEthernet 0/1/16
[*DeviceC] c-rp GigabitEthernet 0/1/16
[*DeviceC] commit
[~DeviceC] quit

# Run the display multicast rpf-info command on Device B to view the RPF information of the source. The command output shows that the RPF route is a unicast route and the RPF neighbor is Device A.

<DeviceB> display multicast rpf-info 10.5.1.2
VPN-Instance: public net
RPF information about source 10.5.1.2:
     RPF interface: GigabitEthernet0/1/0, RPF neighbor: 10.4.1.1
     Referenced route/mask: 10.5.1.0/24
     Referenced route type: unicast
     Route selection rule: preference-preferred
     Load splitting rule: disable

Configure multicast static routes.
# Configure a multicast static route on Device B and specify Device C as an RPF neighbor to the source.
```
<DeviceB> system-view
[~DeviceB] ip rpf-route-static 10.5.1.0 255.255.255.0 10.2.1.2
[*DeviceB] commit
[~DeviceB] quit
```

Verify the configuration.

# Run the display multicast rpf-info command on Device B to view the RPF information of the source. The command output shows that the RPF route and the RPF neighbor are updated based on the multicast static route.

<DeviceB> display multicast rpf-info 10.5.1.2
VPN-Instance: public net
RPF information about source 10.5.1.2:
     RPF interface: GigabitEthernet0/1/8, RPF neighbor: 10.2.1.2
     Referenced route/mask: 10.5.1.0/24
     Referenced route type: mstatic
     Route selection rule: preference-preferred
     Load splitting rule: disable

Configuration Files

Device A configuration file

#
sysname DeviceA
#
multicast routing-enable
#
isis 1
 network-entity 10.0000.0000.0001.00
#
interface GigabitEthernet0/1/0
 undo shutdown
 ip address 10.4.1.1 255.255.255.0
 pim sm
 isis enable 1
#
interface GigabitEthernet0/1/8
 undo shutdown
 ip address 10.5.1.1 255.255.255.0
 pim sm
 isis enable 1
#
interface GigabitEthernet0/1/16
 undo shutdown
 ip address 10.3.1.1 255.255.255.0
 pim sm
 isis enable 1
#
return

Device B configuration file

#
sysname DeviceB
#
multicast routing-enable
#
isis 1
 network-entity 10.0000.0000.0002.00
#
interface GigabitEthernet0/1/0
 undo shutdown
 ip address 10.4.1.2 255.255.255.0
 pim sm
 isis enable 1
#
interface GigabitEthernet0/1/8
 undo shutdown
 ip address 10.2.1.1 255.255.255.0
 pim sm
 isis enable 1
#
interface GigabitEthernet0/1/16
 undo shutdown
 ip address 10.1.1.2 255.255.255.0
 pim sm
 isis enable 1
#
ip rpf-route-static 10.5.1.0 255.255.255.0 10.2.1.2
#
return

Device C configuration file

#
sysname DeviceC
#
multicast routing-enable
#
isis 1
 network-entity 10.0000.0000.0003.00
#
interface GigabitEthernet0/1/8
 undo shutdown
 ip address 10.2.1.2 255.255.255.0
 pim sm
 isis enable 1
#
interface GigabitEthernet0/1/16
 undo shutdown
 ip address 10.3.1.2 255.255.255.0
 pim sm
 isis enable 1
#
pim
 c-bsr GigabitEthernet0/1/16
 c-rp GigabitEthernet0/1/16
#
return

Device D configuration file

#
sysname DeviceD
#
multicast routing-enable
#
isis 1
 network-entity 10.0000.0000.0004.00
#
interface GigabitEthernet0/1/8
 undo shutdown
 ip address 10.6.1.1 255.255.255.0
 pim sm
 igmp enable
 isis enable 1
#
interface GigabitEthernet0/1/16
 undo shutdown
 ip address 10.1.1.1 255.255.255.0
 pim sm
 isis enable 1
#
return