HTLCs: Atomic Payments

Bob forwards a payment and later learns the preimage from Carol. What must he do next?

• Wait for Alice to send him the preimage too
• Use the preimage to claim the matching HTLC from Alice, as soon as possible
• Return the payment to Alice

On a route Alice → Bob → Carol → Dave, which HTLC has the latest expiry?

• Alice → Bob
• Carol → Dave
• They all expire at the same height