- IP Multicast Routing Technology Overview
- Configuring IGMP
- Configuring IGMP Proxy
- Constraining IP Multicast in Switched Ethernet
- Configuring PIM
- Configuring PIM MIB Extension for IP Multicast
- Configuring MSDP
- Configuring Wireless Multicast
- Configuring SSM
- Configuring Basic IP Multicast Routing
- Configuring Multicast Routing over GRE Tunnel
- Configuring the Service Discovery Gateway
- IP Multicast Optimization: Optimizing PIM Sparse Mode in a Large IP Multicast Deployment
- IP Multicast Optimization: Multicast Subsecond Convergence
- IP Multicast Optimization: IP Multicast Load Splitting across Equal-Cost Paths
- IP Multicast Optimization: SSM Channel Based Filtering for Multicast
- IP Multicast Optimization: PIM Dense Mode State Refresh
- IP Multicast Optimization: IGMP State Limit
- Index
Configuring
Multicast Routing over GRE Tunnel
Finding Feature Information
Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Prerequisites for Configuring Multicast Routing over GRE Tunnel
Before configuring multicast routing over GRE, you should be familiar with the concepts of IP Multicast Routing Technology and GRE Tunneling.
Restrictions for Configuring Multicast Routing over GRE Tunnel
The following are the restrictions for configuring multicast routing over GRE tunnel:
-
IPv6 multicast over GRE tunnel is not supported.
-
The total number of supported multicast routes (mroutes) is 2000, across all tunnels.
-
Bidirectional PIM is not supported.
-
Multicast routing should be configured on the first hop router (FHR), the rendezvous point (RP) and the last hop router (LHR) to support multicast over the GRE tunnel.
-
On Catalyst 3850 and Catalyst 3650 series switches, the tunnel source can be a loopback, physical, or L3 EtherChannel interface.
-
No feature interactions such as IPSec, ACL, Tunnel counters, Crypto support, Fragmentation, Cisco Discovery Protocol (CDP), QoS, GRE keepalive, Multipoint GRE, etc. are supported on the GRE Tunnel.
Information About Multicast Routing over GRE Tunnel
Note | Beginning in Cisco IOS XE Denali 16.3.1, multicast routing and NHRP are supported with GRE Tunneling. NHRP can optionally be configured along with the multicast configuration on the tunnel interface to facilitate dynamic discovery of tunnel end points. Please see NHRP for configuring NHRP on a tunnel interface. |
Benefits of Tunneling to Connect Non-IP Multicast Areas
How to Configure Multicast Routing over GRE Tunnel
Configuring a GRE Tunnel to Connect Non-IP Multicast Areas
You can configure a GRE tunnel to transport IP multicast packets between a source and destination that are connected by a medium that does not support multicast routing.
1.
enable
2.
configure
terminal
3.
ip
multicast-routing
4.
interface
tunnel
number
5.
ip address
ip_address
subnet_mask
6.
ip
pim
{
sparse-dense-mode |
sparse-mode |
dense-mode }
7.
tunnel
source
{
ip-address |
interface-name }
8.
tunnel
destination
{
hostname |
ip-address }
9.
end
10.
show interface
type
number
DETAILED STEPS
Tunneling to Connect Non-IP Multicast Areas Example
The following example shows multicast-routing between Catalyst 3650/3850 switch through a GRE tunnel.
In the figure above, the multicast source (10.1.1.1) is connected to Catalyst 3850/3650 Switch-1 and is configured for multicast group 239.1.1.20. The multicast receiver (10.2.2.3) is connected to Catalyst 3850/3650 Switch-2 and is configured to receive multicast packets for group 239.1.1.20. Separating Switch-1 and Switch-2 is an IP cloud, which is not configured for multicast routing.
A GRE tunnel is configured between Switch-1 to Switch-2 sourced with their loopback interfaces. Multicast-routing is enabled on Switch-1 and Switch-2. The ip pim sparse-dense-mode command is configured on tunnel interfaces to support PIM in either the sparse or dense modes. Sparse-dense mode configuration on the tunnel interfaces allows sparse-mode or dense-mode packets to be forwarded over the tunnel depending on rendezvous point (RP) configuration for the group.
Switch-1 Configuration:
Device(config)# ip multicast-routing Device(config)# interface Loopback0 //Tunnel source interface Device(config-if)# ip address 2.2.2.2 255.255.255.255 Device(config)# interface Tunnel 10 //Tunnel interface configured for PIM traffic Device(config-if)# ip address 192.168.24.1 255.255.255.252 Device(config-if)# ip pim sparse-dense-mode Device(config-if)# ip nhrp map 192.168.24.3 4.4.4.4 //NHRP may optionally be configured to dynamically discover tunnel end points. Device(config-if)# ip nhrp map multicast 4.4.4.4 Device(config-if)# ip nhrp network-id 1 Device(config-if)# ip nhrp nhs 192.168.24.3 Device(config-if)# tunnel source Loopback0 Device(config-if)# tunnel destination 4.4.4.4 Device(config)# interface GigabitEthernet 0/0/0 //Source interface Device(config-if)# ip address 10.1.1.2 255.255.255.0 Device(config-if)# ip pim sparse-dense-mode
Switch-2 Configuration:
Device(config)# ip multicast-routing Device(config)# interface Loopback0 //Tunnel source interface Device(config-if)# ip address 4.4.4.4 255.255.255.255 Device(config)# interface Tunnel 10 //Tunnel interface configured for PIM traffic Device(config-if)# ip address 192.168.24.2 255.255.255.252 Device(config-if)# ip nhrp map 192.168.24.4 2.2.2.2 //NHRP may optionally be configured to dynamically discover tunnel end points. Device(config-if)# ip nhrp map multicast 2.2.2.2 Device(config-if)# ip nhrp network-id 1 Device(config-if)# ip nhrp nhs 192.168.24.4 Device(config-if)# ip pim sparse-dense mode Device(config-if)# tunnel source Loopback0 Device(config-if)# tunnel destination 2.2.2.2 Device(config)# interface GigabitEthernet 0/0/0 //Receiver interface Device(config-if)# ip address 10.2.2.2 255.255.255.0 Device(config-if)# ip pim sparse-dense-mode