01
At most three hops
Same hub is two hops. Different hubs is three: endpoint → hub → hub → endpoint. No routing tables.
Inter-ledger settlement
Three hops.
Independent ledgers.
The simplest payment-channel system is a full-mesh routing network, with users as spokes on hubs. Route search is trivial. Coordination needs no chained timeouts — intermediaries never get stuck with someone else’s payment.
One payment
QuoteBitcoin
A
AliceendpointB
BTCHub1her hubAlice never leaves Bitcoin.
Ethereum
B
BTCHub1ETH accountE
EthHub2Béatrice’s hubB
BéatriceendpointHop 2 and 3 live here.
Alice pays béatrice@ethhub2. BTCHub1 quotes BTC in, ETH out.
Hop 1
Bitcoin channel
Alice promises N. BTCHub1 deposits N.
Hop 2
Ethereum channel
BTCHub1 promises N. EthHub2 deposits 3N.
Hop 3
Ethereum channel
EthHub2 promises N. Béatrice deposits 0.
02
No chained timeouts
Staggered deposits replace timeout on the first two hops. No intermediary risks having paid out downstream without getting paid from upstream.
03
Credit clearing by 3-party novation
Hubs accumulate bilateral debts from routing. If A owes B and B owes C, the debt is rerouted so A owes C and B drops out.
Topology
At most three hops.
Same hub: two hops. Different hubs: three. Across ledgers, one of those hubs is the connector — it has a payment channel on the other ledger.
Same hub
Two hops
Alice and Priya sit on the same hub, for example BTCHub1. No second hub. Both hops are Bitcoin channels.
Alice → BTCHub1 → Priya
Same ledger
Two hubs on the same ledger
Alice and Dave use different hubs on the same ledger, for example Bitcoin. Hop 2 is the channel between those hubs.
Alice → BTCHub1 → BTCHub2 → Dave
Connector
Inter-hub channel between ledgers
Endpoints sit on different ledgers. One hub is the connector and holds a payment channel on the other ledger, for example Bitcoin to Ethereum, so hop 2 can settle there.
Alice → BTCHub1 → EthHub2 → Béatrice
Locked capital
Griefing is economically irrational.
The party that can cancel has locked as much as everyone else combined. On hop 2 that is 3N — the sum of the upstream deposits.
Hop 1 · Alice → hub
Alice N · hub N · Hub can cancel — same as Alice
Hop 2 · Hub → hub
Hub₁ N · hub₂ 3N · Hub₂ can cancel — 3N equals the sum of upstream deposits
Hop 3 · Hub → Béatrice
Hub N · receiver 0 · Timeout only
Send a payment across ledgers.
A simulation — quote, prepare, reveal the preimage, commit backward. Or cancel from the last hop and watch deposits unwind.