Banff Changes

This document specifies the changes in Metal “Banff”, which will be released in MetalGo v1.9.x.

Block Changes

Apricot

Apricot allows the following block types with the following content:

• Standard Blocks may contain multiple transactions of the following types:
  • CreateChainTx
  • CreateSubnetTx
  • ImportTx
  • ExportTx
• Proposal Blocks may contain a single transaction of the following types:
  • AddValidatorTx
  • AddDelegatorTx
  • AddSubnetValidatorTx
  • RewardValidatorTx
  • AdvanceTimeTx
• Options Blocks, that is Commit Block and Abort Block do not contain any transactions.

Each block has a header containing:

• ParentID
• Height

Banff

Banff allows the following block types with the following content:

• Standard Blocks may contain multiple transactions of the following types:

  • CreateChainTx
  • CreateSubnetTx
  • ImportTx
  • ExportTx
  • AddValidatorTx
  • AddDelegatorTx
  • AddSubnetValidatorTx
  • RemoveSubnetValidatorTx
  • TransformSubnetTx
  • AddPermissionlessValidatorTx
  • AddPermissionlessDelegatorTx

• Proposal Blocks may contain a single transaction of the following types:

  • RewardValidatorTx

• Options blocks, that is Commit Block and Abort Block do not contain any transactions.

Note that each block has an header containing:

• ParentID
• Height
• Time

So the two main differences with respect to Apricot are:

• AddValidatorTx, AddDelegatorTx, AddSubnetValidatorTx are included into Standard Blocks rather than Proposal Blocks so that they don't need to be voted on (that is followed by a Commit/Abort Block).
• New Transaction types: RemoveSubnetValidatorTx, TransformSubnetTx, AddPermissionlessValidatorTx, and AddPermissionlessDelegatorTx have been added into Standard Blocks.
• Block timestamp is explicitly serialized into block header, to allow chain time update.

New Transactions

RemoveSubnetValidatorTx

type RemoveSubnetValidatorTx struct {
    BaseTx `serialize:"true"`
    // The node to remove from the subnet.
    NodeID ids.NodeID `serialize:"true" json:"nodeID"`
    // The subnet to remove the node from.
    Subnet ids.ID `serialize:"true" json:"subnet"`
    // Proves that the issuer has the right to remove the node from the subnet.
    SubnetAuth verify.Verifiable `serialize:"true" json:"subnetAuthorization"`
}

TransformSubnetTx

type TransformSubnetTx struct {
    // Metadata, inputs and outputs
    BaseTx `serialize:"true"`
    // ID of the Subnet to transform
    // Restrictions:
    // - Must not be the Primary Network ID
    Subnet ids.ID `serialize:"true" json:"subnetID"`
    // Asset to use when staking on the Subnet
    // Restrictions:
    // - Must not be the Empty ID
    // - Must not be the METAL ID
    AssetID ids.ID `serialize:"true" json:"assetID"`
    // Amount to initially specify as the current supply
    // Restrictions:
    // - Must be > 0
    InitialSupply uint64 `serialize:"true" json:"initialSupply"`
    // Amount to specify as the maximum token supply
    // Restrictions:
    // - Must be >= [InitialSupply]
    MaximumSupply uint64 `serialize:"true" json:"maximumSupply"`
    // MinConsumptionRate is the rate to allocate funds if the validator's stake
    // duration is 0
    MinConsumptionRate uint64 `serialize:"true" json:"minConsumptionRate"`
    // MaxConsumptionRate is the rate to allocate funds if the validator's stake
    // duration is equal to the minting period
    // Restrictions:
    // - Must be >= [MinConsumptionRate]
    // - Must be <= [reward.PercentDenominator]
    MaxConsumptionRate uint64 `serialize:"true" json:"maxConsumptionRate"`
    // MinValidatorStake is the minimum amount of funds required to become a
    // validator.
    // Restrictions:
    // - Must be > 0
    // - Must be <= [InitialSupply]
    MinValidatorStake uint64 `serialize:"true" json:"minValidatorStake"`
    // MaxValidatorStake is the maximum amount of funds a single validator can
    // be allocated, including delegated funds.
    // Restrictions:
    // - Must be >= [MinValidatorStake]
    // - Must be <= [MaximumSupply]
    MaxValidatorStake uint64 `serialize:"true" json:"maxValidatorStake"`
    // MinStakeDuration is the minimum number of seconds a staker can stake for.
    // Restrictions:
    // - Must be > 0
    MinStakeDuration uint32 `serialize:"true" json:"minStakeDuration"`
    // MaxStakeDuration is the maximum number of seconds a staker can stake for.
    // Restrictions:
    // - Must be >= [MinStakeDuration]
    // - Must be <= [GlobalMaxStakeDuration]
    MaxStakeDuration uint32 `serialize:"true" json:"maxStakeDuration"`
    // MinDelegationFee is the minimum percentage a validator must charge a
    // delegator for delegating.
    // Restrictions:
    // - Must be <= [reward.PercentDenominator]
    MinDelegationFee uint32 `serialize:"true" json:"minDelegationFee"`
    // MinDelegatorStake is the minimum amount of funds required to become a
    // delegator.
    // Restrictions:
    // - Must be > 0
    MinDelegatorStake uint64 `serialize:"true" json:"minDelegatorStake"`
    // MaxValidatorWeightFactor is the factor which calculates the maximum
    // amount of delegation a validator can receive.
    // Note: a value of 1 effectively disables delegation.
    // Restrictions:
    // - Must be > 0
    MaxValidatorWeightFactor byte `serialize:"true" json:"maxValidatorWeightFactor"`
    // UptimeRequirement is the minimum percentage a validator must be online
    // and responsive to receive a reward.
    // Restrictions:
    // - Must be <= [reward.PercentDenominator]
    UptimeRequirement uint32 `serialize:"true" json:"uptimeRequirement"`
    // Authorizes this transformation
    SubnetAuth verify.Verifiable `serialize:"true" json:"subnetAuthorization"`
}

AddPermissionlessValidatorTx

type AddPermissionlessValidatorTx struct {
    // Metadata, inputs and outputs
    BaseTx `serialize:"true"`
    // Describes the validator
    Validator validator.Validator `serialize:"true" json:"validator"`
    // ID of the subnet this validator is validating
    Subnet ids.ID `serialize:"true" json:"subnet"`
    // Where to send staked tokens when done validating
    StakeOuts []*avax.TransferableOutput `serialize:"true" json:"stake"`
    // Where to send validation rewards when done validating
    ValidatorRewardsOwner fx.Owner `serialize:"true" json:"validationRewardsOwner"`
    // Where to send delegation rewards when done validating
    DelegatorRewardsOwner fx.Owner `serialize:"true" json:"delegationRewardsOwner"`
    // Fee this validator charges delegators as a percentage, times 10,000
    // For example, if this validator has DelegationShares=300,000 then they
    // take 30% of rewards from delegators
    DelegationShares uint32 `serialize:"true" json:"shares"`
}

AddPermissionlessDelegatorTx

type AddPermissionlessDelegatorTx struct {
    // Metadata, inputs and outputs
    BaseTx `serialize:"true"`
    // Describes the validator
    Validator validator.Validator `serialize:"true" json:"validator"`
    // ID of the subnet this validator is validating
    Subnet ids.ID `serialize:"true" json:"subnet"`
    // Where to send staked tokens when done validating
    Stake []*avax.TransferableOutput `serialize:"true" json:"stake"`
    // Where to send staking rewards when done validating
    RewardsOwner fx.Owner `serialize:"true" json:"rewardsOwner"`
}

New TypeIDs

ApricotProposalBlock = 0
ApricotAbortBlock = 1
ApricotCommitBlock = 2
ApricotStandardBlock = 3
ApricotAtomicBlock = 4

secp256k1fx.TransferInput = 5
secp256k1fx.MintOutput = 6
secp256k1fx.TransferOutput = 7
secp256k1fx.MintOperation = 8
secp256k1fx.Credential = 9
secp256k1fx.Input = 10
secp256k1fx.OutputOwners = 11

AddValidatorTx = 12
AddSubnetValidatorTx = 13
AddDelegatorTx = 14
CreateChainTx = 15
CreateSubnetTx = 16
ImportTx = 17
ExportTx = 18
AdvanceTimeTx = 19
RewardValidatorTx = 20

stakeable.LockIn = 21
stakeable.LockOut = 22

RemoveSubnetValidatorTx = 23
TransformSubnetTx = 24
AddPermissionlessValidatorTx = 25
AddPermissionlessDelegatorTx = 26

EmptyProofOfPossession = 27
BLSProofOfPossession   = 28

BanffProposalBlock = 29
BanffAbortBlock = 30
BanffCommitBlock = 31
BanffStandardBlock = 32