Example for Configuring PIM over GRE Tunnel
- Tracy Yang
Owned by Tracy Yang
Nov 13, 2023
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Networking Requirements
Figure 1. PIM over GRE Tunnel Configuration Example
As shown in Figure 1, multicast services are deployed in the network. Switch B does not support multicast protocols, so multicast traffic needs to be transmitted between Switch A and Switch C through a GRE tunnel.
Follow the configuration roadmap below to configure PIM over GRE tunnel.
- Run OSPF route protocol on Switch A, Switch B and Switch C for underlay communication.
- Create GRE tunnel interfaces on Switch A and Switch C to establish a GRE tunnel; Run BGP route protocol on GRE tunnel interfaces.
- Enable PIM function on the GRE tunnel interfaces to enable the transmission of multicast packets by the GRE tunnel.
Procedure
Switch A
Step1 Configure VLAN interface.
admin@SwitchA# set vlans vlan-id 11 l3-interface vlan11 admin@SwitchA# set vlans vlan-id 22 l3-interface vlan22 admin@SwitchA# set interface gigabit-ethernet te-1/1/45 family ethernet-switching native-vlan-id 11 admin@SwitchA# set interface gigabit-ethernet te-1/1/13 family ethernet-switching native-vlan-id 22 admin@SwitchA# set l3-interface loopback lo address 100.100.100.100 prefix-length 32 admin@SwitchA# set l3-interface vlan-interface vlan11 address 10.1.1.2 prefix-length 24 admin@SwitchA# set l3-interface vlan-interface vlan22 address 10.20.1.1 prefix-length 24
Step2 Enable IP routing.
admin@SwitchA# set ip routing enable true
Step3 Configure OSPF route protocol for underlay communication.
admin@SwitchA# set protocols ospf router-id 1.1.1.1 admin@SwitchA# set protocols ospf network 10.20.1.0/24 area 0 admin@SwitchA# set protocols ospf network 100.100.100.100/32 area 0
Step4 Configure GRE tunnel name, IP, source IP, destination IP etc.
admin@SwitchA# set l3-interface tunnel tnl0 address 10.40.1.1 prefix-length 24 admin@SwitchA# set l3-interface tunnel tnl0 tunnel-mode gre-ip admin@SwitchA# set l3-interface tunnel tnl0 source 100.100.100.100 admin@SwitchA# set l3-interface tunnel tnl0 destination 200.200.200.200
Step5 Configure BGP route protocol for the GRE tunnel.
admin@SwitchA# set protocols bgp local-as 100 admin@SwitchA# set protocols bgp ebgp-requires-policy false admin@SwitchA# set protocols bgp neighbor 10.40.1.2 remote-as 200 admin@SwitchA# set protocols bgp ipv4-unicast network 10.1.1.0/24
Step6 Enable PIM on the GRE tunnel interface, configure Switch A’s GRE tunnel interface as the static RP.
admin@SwitchA# set protocols pim interface vlan11 sm admin@SwitchA# set protocols pim interface tnl0 sm admin@SwitchA# set protocols pim rp 10.40.1.1 group 225.0.0.0/8
Step7 Commit the configuration.
admin@SwitchA# commit
Switch B
Step1 Configure VLAN interface.
admin@SwitchB# set vlans vlan-id 22 l3-interface vlan22 admin@SwitchB# set vlans vlan-id 33 l3-interface vlan33 admin@SwitchB# set interface gigabit-ethernet ge-1/1/3 family ethernet-switching native-vlan-id 22 admin@SwitchB# set interface gigabit-ethernet te-1/1/1 family ethernet-switching native-vlan-id 33 admin@SwitchB# set l3-interface vlan-interface vlan22 address 10.20.1.2 prefix-length 24 admin@SwitchB# set l3-interface vlan-interface vlan33 address 10.30.1.1 prefix-length 24
Step2 Enable IP routing.
admin@SwitchB# set ip routing enable true
Step3 Configure OSPF for the connections between Switch A, Switch B and Switch C.
admin@SwitchB# set protocols ospf router-id 2.2.2.2 admin@SwitchB# set protocols ospf network 10.30.1.0/24 area 0 admin@SwitchB# set protocols ospf network 10.20.1.0/24 area 0
Step4 Commit the configuration.
admin@SwitchB# commit
Switch C
Step1 Configure VLAN interface.
admin@SwitchC# set vlans vlan-id 33 l3-interface vlan33 admin@SwitchC# set vlans vlan-id 44 l3-interface vlan44 admin@SwitchC# set interface gigabit-ethernet te-1/1/17 family ethernet-switching native-vlan-id 33 admin@SwitchC# set interface gigabit-ethernet te-1/1/23 family ethernet-switching native-vlan-id 44 admin@SwitchC# set l3-interface loopback lo address 200.200.200.200 prefix-length 32 admin@SwitchC# set l3-interface vlan-interface vlan33 address 10.30.1.2 prefix-length 24 admin@SwitchC# set l3-interface vlan-interface vlan44 address 10.2.1.2 prefix-length 24
Step2 Enable IP routing.
admin@SwitchC# set ip routing enable true
Step3 Configure OSPF routes for underlay communication.
admin@SwitchC# set protocols ospf router-id 3.3.3.3 admin@SwitchC# set protocols ospf network 10.30.1.0/24 area 0 admin@SwitchC# set protocols ospf network 200.200.200.200 area 0
Step4 Configure GRE tunnel name, IP, source IP, destination IP etc.
admin@SwitchC# set l3-interface tunnel tnl0 address 10.40.1.2 prefix-length 24 admin@SwitchC# set l3-interface tunnel tnl0 tunnel-mode gre-ip admin@SwitchC# set l3-interface tunnel tnl0 source 200.200.200.200 admin@SwitchC# set l3-interface tunnel tnl0 destination 100.100.100.100
Step5 Configure BGP routes for the GRE tunnel.
admin@SwitchC# set protocols bgp local-as 200 admin@SwitchC# set protocols bgp ebgp-requires-policy false admin@SwitchC# set protocols bgp neighbor 10.40.1.1 remote-as 100 admin@SwitchC# set protocols bgp ipv4-unicast network 10.2.1.0/24
Step6 Enable PIM on the GRE tunnel interface, configure Switch A’s GRE tunnel interface as the static RP.
admin@SwitchC# set protocols pim interface vlan33 sm admin@SwitchC# set protocols pim interface tnl0 sm admin@SwitchC# set protocols pim rp 10.40.1.1 group 225.0.0.0/8
Step7 Configure the IGMP function of the connected receiver interface.
admin@SwitchC# set protocols igmp interface vlan44
Step8 Commit the configuration.
admin@SwitchC# commit
Verifying the Configuration
- After the configuration is complete, run run show pim interface to view the configuration and operation state of PIM on an interface.
admin@switchA# run show pim interface Interface State Address PIM Nbrs PIM DR FHR IfChannels tnl0 up 10.40.1.1 1 10.40.1.2 0 2 pimreg up 0.0.0.0 0 local 0 0 vlan11 up 10.1.1.2 0 local 0 0 admin@switchC# run show pim interface Interface State Address PIM Nbrs PIM DR FHR IfChannels tnl0 up 10.40.1.2 1 local 0 0 pimreg up 0.0.0.0 0 local 0 0 vlan44 up 10.2.1.2 0 local 0 2
- Run command run show l3-interface tunnel to display information about the GRE tunnel interface.
admin@SwitchA# run show l3-interface tunnel tnl0 tnl0 State:UP Tunnel Source: 100.100.100.100 Tunnel Destnation: 200.200.200.200 Tunnel protocol/transport: gre-ip Inet addr: 10.40.1.1 Traffic statistics: 5 sec input rate IPv4 1200 packets/sec, IPv6 0 packets/sec 5 sec forwarding rate IPv4 80 packets/sec, IPv6 0 packets/sec IPv4 Input Packets............................28 IPv4 Forwarding Packets.......................5 IPv6 Input Packets............................0 IPv6 Forwarding Packets.......................0
- Run commands run show pim neighbor and run show pim rp-info to that the PIM neighbor information and RP information have been generated correctly.
admin@switchA# run show pim neighbor Interface Neighbor Uptime Holdtime DR Pri tnl0 10.40.1.2 03:10:40 00:01:34 1 admin@switchA# run show pim rp-info RP address group/prefix-list OIF I am RP Source Group-Type 10.40.1.1 225.0.0.0/8 tnl0 yes Static ASM
- In this example, multicast source 10.1.1.5 sends multicast information to multicast group 225.0.0.2. The multicast routing table generated by PIM protocol can be viewed through the run show mroute command, which shows that multicast traffic can be transmitted through the GRE tunnel.
admin@switchA# run show mroute IP Multicast Routing Table Flags: S - Sparse, C - Connected, P - Pruned R - SGRpt Pruned, F - Register flag, T - SPT-bit set Source Group Flags Proto Input Output TTL Uptime * 225.0.0.2 S none tnl0 none 0 --:--:-- 10.1.1.5 225.0.0.2 SFT PIM vlan11 pimreg 1 02:59:50 STAR tnl0 1 admin@switchC# run show mroute IP Multicast Routing Table Flags: S - Sparse, C - Connected, P - Pruned R - SGRpt Pruned, F - Register flag, T - SPT-bit set Source Group Flags Proto Input Output TTL Uptime * 225.0.0.2 SC IGMP tnl0 pimreg 1 03:07:44 IGMP vlan44 1 10.1.1.5 225.0.0.2 ST STAR tnl0 vlan44 1 03:07:17
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