IP-IP

The IP-IP (IP-in-IP) layer wraps an inner IP packet in an outer IP header without GRE. Configure it under Library → Network Tunnels.

Table — IP-IP Layer Parameters

Name	Description	Value
Local IP	Outer source IP	Address of the local tunnel end
Remote IP	Outer destination IP	Remote-end/DUT address

IP-IP is usually simpler than GRE and has fewer header options. Use it when the DUT expects IP-in-IP rather than GRE. In a stack with VLAN/IPsec, check the layer order and MTU: every outer header reduces the available payload size.