Mainnet began on block 148,888. It supports 32 GiB and 64 GiB sectors.
This network suffers frequent resets and is not recommended for most users.
Calibration network is the most realistic simulation of the Filecoin mainnet:

- Prospective storage miners can experience more realistic sealing performance and hardware requirements due to the use of final proofs constructions and parameters
- Prospective storage clients can store and retrieve real data on the network. Clients can participate in deal-making workflows and storage + retrieval functionality.
- Same as mainnet, the calibration network supports 32 GiB and 64 GiB sectors with an additional 512MiB sector.
The Nerpa network was named after a species of seal, one of the smallest true seals.