Fee and Reward
Anyone who wants to access the Relay data to prove the inclusion of a state or transaction on the source chain should pay the Relay fee. This fee compensates the Relayers who provide the Relay contract with the source chain data. There is no way to access the Relay data without paying the fee since the data is stored in private variables.
Relay users can pay fees either using the native token of the blockchain or TDT. TeleportDAO calculates the required amount of user fee in epochs of block headers, based on the cost of submitting a block header on Relay and Relay usage rate.
The number of blocks in one epoch is such that we can estimate the number of queries sent to Relay in an epoch using the number of queries in the previous epoch. Therefore, the fee that a user needs to pay for verifying some data decreases if the total number of requests had increased in the previous epoch.
To avoid too much increase in the relay fee (when the usage rate is low), we assume a base number for queries in an epoch. The excess fee from high usage epochs gets accumulated in the Relay contract. This amount is used to pay the Relayers whose block headers have been in an epoch with less than the base number of queries.
The amount of fee that a Relay user needs to pay for using a block header data is:
- G = block header submission gas usage
- P = gas price (at the time of submitting the block header)
- N = number of previous epoch queries
- B = base number of queries
- M = number of blocks in one epoch
The Relayer reward consists of two parts: TDT token, and Relay reward. The TDT token comes from the TeleportDAO treasury. As the number of bridge users grows, the treasury reward will decrease. The Relay reward comes from collected Relay fees to compensate Relayers for block header submission gas costs. This reward is calculated as follows:
Note: Relayers may not get the full Relay reward if the Relay contract runs out of the native token. This can happen if the Relay usage is low for a while, so the collected fees are not sufficient to compensate Relayers. To incentive Relayers to keep their work, we compensate them with TDT from the TeleportDAO treasury. In the long run, we expect that there is enough usage for Relay, so the collected fees are enough to compensate Relayers. Also, as the TeleportDAO team, we will run a Relayer node which submits block headers in any case (whether there are enough collected fees or not).