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Filecoin and IPFS interactions

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lukemarsden edited this page Apr 27, 2022 · 24 revisions

ipfs vs filecoin

A quick summary of our understanding of how IPFS and Filecoin relate to each other.

Libp2p provides most of the IPFS functionality:

  • a connected mesh of peers
  • content-addressed routing (via the DHT)
  • a protocol to copy files around (bitswap)

libp2p let's us multiplex protocols on the wire so peers can communicate to each other using any of the protocols they have agreed upon to understand.

So, when we say IPFS what we mean is libp2p using the bitswap protocol plus a blockstore which is IPLD content saved to disk in sectors.

Filecoin also uses libp2p (on a distinctly different network of peers) - but it uses it's own suite of libp2p protocols (including graphsync).

In simple terms - ipfs and filecoin share the libp2p codebase but implement their own protocols; lotus does not use go-ipfs under the hood, these are distinctly different projects that run on different networks of peers.

notes and open questions

I do not believe that you can actually “ignore IPFS completely” for what you intend to do

Unless you will design a side-protocol to distributed the computations to be run

  • The above means "how are you going to transport the compute to the node that will run it?"
    • You can use IPFS
    • You can write your own protocol
    • (lets just use IPFS)

The thinking here is that:

QUESTION - does Lotus run IPFS in-process? The Lotus install docs don't specify needing to separately install an IPFS node, but the code looks like it's assuming an IPFS server is (can be) running locally.

ANSWER - No - Lotus uses libp2p and bitswap which is the same as ipfs but it does not run the ipfs server under the hood

QUESTION - is the filecoin network two layered networks (IPFS + blockchain on top) or is it all one libp2p mesh?

ANSWER - No - it is a single network with 3 multiplexed protocols (because libp2p lets you do that (neat)) - bitswap, graphsync and filecoin specific protocol (streaming protocol to update the chain)

QUESTION - when specifying, say, a list of CIDs for a Bacalhau job to run on, would we expect to be able to specify CIDs in the IPFS network, or the Filecoin network? In the latter case, they would be sealed, and need to be unsealed. Assuming we specify the CIDs as IPLD addresses, can IPLD reference files in the Filecoin network?

NOTES - look at the IPFS codebase and find out how to check if a CID lives locally in the repository - do the same with the filecoin codebase and confirm that the format of the CID is the same. Put another way - are CID's truely content addressable and transferable between both networks?

ANSWER - Yes - CID's are the content addressable ids for CAR files (Content Addressable Archives) and these are used both by IPFS and Filecoin. So - it is reasonable to say:

QUESTION - out of curiosity, how do the Filecoin and IPFS networks avoid interfering with eachother, by, say, a node that connects to both at the same time by accident?

NOTES - It's not designed to work this way. IPFS and Filecoin are distinct networks from each other - although they both use libp2p so it is theoretically possible e.g. for a Lotus node to connect to the IPFS network but it would have to speak the right layered protocols in order to interact with it.

QUESTION - what does Filecoin actually store in its IPFS network? Is it sealed sectors, or something else? Is IPFS used as a way to specify data that is an input to a Filecoin deal?

ANSWER - Filecoin doesn't actually have it's own IPFS network - it just communicates with other nodes over libp2p in the same way. It stores data in directories that the daemon is responsible for reading and writing to. In other words Lotus is stateful and it's a proxy onto some IPFS thing.

OPEN QUESTION: do both IPFS and Filecoin save CAR files to disk

OPEN QUESTION: is an IPFS repo (i.e. on disk storage) compatible with Filecoin?

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