Define standard L2 Transaction Fee Structure

[Therecanbeonlyone1969]

In connection with issue #21 it is necessary to accommodate different fee structures and how they are calculated across L2s.

Define a new Ethereum transaction type with execution on Layer 2 and what data needs to be published to Layer 1.

[bossyuansu]

also the transparency of the pricing. So far L2s are presenting the fees to the user in different ways.

[Therecanbeonlyone1969]

Can we define a basic fee structure e.g.:

• base fee -> minimal fee to cover node operation
• execution fee -> cost for executing a transaction
• priority fee -> fee to pay to validators/sequencers to move to the front of the execution queue
  ?

[DZGoldman]

Can give the details with respect to Arbitrum:
Arbitrum tx fees comprise 2 dimensions: the L2 fee (L2 base fee * L2 gas limit) + the L1 fee (price per unit of L1 data * estimated L1 calldata used). This ultimately gets surfaced by RPCs to conform to the fee structure described in the previous comment, for ease of client side integration, as such:

• base fee: l2 gas price; responds to L2 congestion ala L1 Ethereum. Has a set floor price (0.1 gwei on Arbitrum One as of writing).
• "execution fee": value that when multiplied by base fee will be sufficient to cover both the L2 and L1 fees; i.e.,
  L2 gas limit + ( L1 fee) / (L2 gas price)
• priority fee: currently a noop; moving forward / with decentralized sequencing, the current thinking is that it will by the tx ordering priority within a fixed "fairness granularity" time-window; see here

[Therecanbeonlyone1969]

Transaction Feee definitions completed and PR #34 merged

[Therecanbeonlyone1969]

Type of requirements needed for specification:

• define transaction
• define roles for fee visibility -- tx originator, tx sender (might be intermediary), developer, L2 operator
• define transaction types: direct transactions (tx originator to L2), meta-transactions (intermediary to L2),
• give transaction examples on tx originator and intermediary (focus on control by tx originator(s) on intermediary)
• give examples of types of control -> note that control can move between entities
• requirements on intermediaries to create fee visibility
• intermediary transactions as internal transactions
• require full fee transparency from the intermediary on fees charged to the intermediary for the tx originator
• explain why we might have zero fees (meta-transactions)
• fee communication to end-users and developers -- how, when, and where
• fee estimates
• final fees
• final fees vs fee estimates
• reorgs (challenged trxns in optimistic rollups, non finalized blocks in zk-rollups) --> what happens with paid fees? Reimbursed? Lost?

Out of scope: L2 <-> L2 bridge fees (separate workitem), Fees between L2s and centralized exchanges

[Therecanbeonlyone1969]

See PR #43 for a first full draft of the transaction fee specification

[Therecanbeonlyone1969]

Closing issue for now after merging PR #43