Overview
This proposal is about implementing proper multihoming support in I2P that can scale up to large sites.
Motivation
Multihoming is a hack and presumably won’t work for e.g. facebook.i2p at scale. Say we had 100 multihomes each with 16 tunnels, that’s 1600 LS publishes every 10 minutes, or almost 3 per second. The floodfills would get overwhelmed and throttles would kick in. And that’s before we even mention the lookup traffic.
We need some sort of meta-LS, where the LS lists the 100 real LS hashes. This would be long-lived, a lot longer than 10 minutes. So it’s a two-stage lookup for the LS, but the first stage could be cached for hours.
Specification
The meta-LeaseSet would have the following format::
Destination
Published Time stamp
Expiration
Flags
Properties
Number of entries
Number of revocations
Entries. Each entry contains:
- Hash
- Flags
- Expiration
- Cost (priority)
- Properties
Revocations. Each revocation contains:
- Hash
- Flags
- Expiration
Signature
Flags and properties are included for maximum flexibility.
Comments
This could then be generalized to be a service lookup of any type. The service identifier is a SHA256 hash.
For even more massive scalability, we could have multiple levels, i.e. a meta-LS could point to other meta-LSes.