Kademlia... that's distributed hash tables, aka DHT. DHT uses servers to lookup and locate nodes. Therefore it's not truly distributed, thus not P2P.
In contrast, the Xnode protocol, upon which the XBridge is based, is completely serverless in operation and truly distributed.
So what exactly will XBridge use?
I'm told Telehash v.3.
Mesh networking - like XCurrency, and a bit of DHT too for scalability.
Completely serverless of course.
https://github.com/telehash/telehash.org/tree/v3/v3
the focus for v3 is to enable private communication between SMALL numbers of TRUSTED nodes
We are combining the best of DHT with XNode, and Telehash technologies to build XBRIDGE