The multicast-vpn ttl propagate command configures an ingress PE to copy the TTL in an MVPN packet to a public network multicast packet.
The undo multicast-vpn ttl propagate command cancels the configuration.
By default, an ingress PE does not copy the TTL in an MVPN packet to a public network multicast packet, and the TTL in a public network multicast packet is 255.
Usage Scenario
The multicast-vpn ttl propagate command is used on an ingress PE. When MVPN is deployed, MVPN data packets need to be transmitted over a public network, and the public network is transparent, the ingress PE copies the TTLs in the MVPN data packets into public network multicast packets. The egress PE does not copy the TTL values when removing the public network header from the packets.
Configuration Impact
If the TTL in an MVPN packet is too small, the packet is discarded on the public network when the TTL is reduced to 0.