This topic describes how the Cisco 8000 Series Router controls the TTL value of the inner payload header of IP-in-IP tunnel packets before the packets are forwarded to the next-hop router.
The IP-in-IP tunnel configurations are network settings that
-
control the TTL value of inner payload headers
-
enable a router to forward custom-formed IP-in-IP stacked packets even if the inner packet TTL is 1, and
-
facilitate end-to-end link-state and path reachability measurements.
The Cisco 8000 Series Router maintains specific operational behaviors for IP-in-IP tunnels:
-
After you enable or disable the decrement of the TTL value of the inner payload header of a packet, you do not need to reload the line card.
-
The router allows you to control the TTL value of the inner payload header of IP-in-IP tunnel packets before forwarding them to the next-hop router.
-
The router supports a maximum of 16 IP-in-IP decapsulation tunnels with unique source addresses starting from Cisco IOS XR Release 7.3.3.
-
The system updates the TTL decrement setting without requiring a line card reload.
-
The OOR State displays Red in the show controllers npu resources sipidxtbl location all command output.