I found this old diagram from 2004, describing a easy way to use ICE on Jingle. It also describes in a very simplistic way how it works.
Main differences from regular ICE, are that in the suggested flow, there is no need for STUN connectivity check, everything is done by an ECHO service that justs replies every UDP packet to the sender.
The relay candidates are also not retrieved from a TURN Server, but from an XMPP Service that provide ready to use relay candidates.
Skipping STUN Conn-Check and TURN complexity.
This proposal will be used as an inspiration for Jingle Super Nodes XEP.