# [−][src]Module zebra_chain::parameters

Consensus parameters for each Zcash network.

This module contains the consensus parameters which are required for parsing.

Some consensus parameters change based on network upgrades. Each network upgrade happens at a particular block height. Some parameters have a value (or function) before the upgrade height, at the upgrade height, and after the upgrade height. (For example, the value of the reserved field in the block header during the Heartwood upgrade.)

Typically, consensus parameters are accessed via a function that takes a Network and block::Height.

## Structs

 ConsensusBranchId The Consensus Branch Id, used to bind transactions and blocks to a particular network upgrade.

## Enums

 Network An enum describing the possible network choices. NetworkUpgrade A Zcash network upgrade.

## Constants

 GENESIS_PREVIOUS_BLOCK_HASH The previous block hash for the genesis block. POW_AVERAGING_WINDOW The averaging window for difficulty threshold arithmetic mean calculations. TESTNET_MAX_TIME_START_HEIGHT The activation height for the block maximum time rule on Testnet.

## Functions

 genesis_hash Returns the hash for the genesis block in network.