Filecoin
रिट्रीवल बाजार प्रोटोकॉल
Context
Figure 12 closes Section 5.3.3 (The Retrieval Market Protocol) and presents the complete two-phase Retrieval Market protocol. It is the definitive technical specification for how data retrieval is accomplished in Filecoin without on-chain settlement, using off-chain gossip and micropayment channels instead.
What This Figure Shows
The Order Matching phase has two steps. Step 1: Retrieval Miners and Clients gossip ask and bid orders via Get.addOrders; since there is no shared on-chain orderbook, users maintain their own partial view and no resources are committed upfront. Step 2: miner and client independently run Get.matchOrders against their local orderbook views; both sign the deal order and add it to their local orderbook; they set up a micropayment channel. The Settlement phase has two steps. Step 3: the miner sends the piece in parts, with each part accompanied by a Merkle path; the client receives each part, verifies the Merkle path, and sends a micropayment acknowledgment for each part. Step 4: when the client has received the full piece, the miner presents the accumulated micropayments to the network to retrieve payment, and both parties remove their orders.
Significance
The Retrieval Market's off-chain gossip orderbook and micropayment settlement model represents a fundamental architectural trade-off: on-chain settlement would provide strong guarantees but is too slow for data retrieval, so Filecoin instead uses an incremental exchange protocol where neither party can cheat by more than one piece segment. The Merkle-path-per-segment verification ensures the client can confirm data integrity without downloading the whole file first, a direct application of content-addressing.
