There are several delays built in to Lightning.
Time Lock Delta / CLTV delta
- Time Lock Delta is the same as CLTV delta
- It is a setting in the channel
- each hop has a time delta, when you include that hop that delta gets added to the final absolute HTLC that the sender sends out
- if each hop has a 1 block delta, and there are 3 hops, then if we’re at height 0, the cltv expiry the sender uses for that first htlc is 3