There are a number of optional parameters that may be present in an Internet Protocol version 4 datagram.
[2] Loose Source Routing is an IP option which can be used for address translation.
By setting the forwarding agent (FA) to one of the routers that the packet must visit, LSR is equivalent to tunneling.
If the corresponding node stores the LSR options and reverses it, it is equivalent to the functionality in mobile IPv6.
The name loose source routing comes from the fact that only part of the path is set in advance.