Proposal: Open HRMP channel between Moonriver and Bifrost

TL:DR

Similar to other HRMP channel proposals, we propose to open an HRMP channel between Moonriver and Bifrost.

Summary

We propose to open a bi-directional channel between Bifrost and Moonriver. Initially, the main use case will be to transfer MOVR and BNC between the two chains, but it can be further expanded to other use cases.

Proposal

https://polkadot.js.org/apps/?rpc=wss%3A%2F%2Fbifrost-rpc.liebi.com%2Fws#/democracy

Technical details:

The procedure for opening the channels is as follows:

  1. Moonriver: democracy proposal to open Moonriver to Bifrost HRMP channel
  2. Bifrost: democracy proposal to open Bifrost to Moonriver HRMP channel
  3. Wait until the proposals on step 1 & 2 get approved & enacted
  4. Bifrost: democracy proposal to accept Moonriver to Bifrost HRMP channel
  5. Moonriver: democracy proposal to accept Bifrost to Moonriver HRMP channel
  6. Wait until proposals on step 3 & 4 get approved & enacted
  7. Bifrost: wait one session after each acceptance for each channel to be opened
  8. XCM based cross-chain transfer will be possible at this stage

The extrinsics that need to be executed on the relay chain , are:

  • For step 1: hrmp.hrmpInitOpenChannel(recipient: 2023, proposedMaxCapacity: 1000, proposedMaxMessageSize: 102400) , which its hex-encoded call data is 0x3c00e7070000e803000000900100
  • For step 2: hrmp.hrmpInitOpenChannel(recipient: 2001, proposedMaxCapacity: 1000, proposedMaxMessageSize: 102400) , which its hex-encoded call data is 0x3c00d1070000e803000000900100
  • For step 4: hrmp.hrmpAcceptOpenChannel(sender: 2023) , which hex-encoded call data is 0x3c01e7070000
  • For step 5: hrmp.hrmpAcceptOpenChannel(sender: 2001) , which its hex-encoded call data is 0x3c01d1070000

The proposedMaxCapacity and proposedMaxMessageSize are set to the values of Kusama’s configuration.activeConfig.hrmpChannelMaxCapacity and configuration.activeConfig.hrmpChannelMaxMessageSize values, respectively.

These extrinsics need to be called from the parachain’s sovereign account as origin, via a democracy proposal. The proposal will use polkadotXcm pallet to send XCM message to the Relay Chain with the following items:

  • Withdraw asset: take funds out of the Sovereign Account of the origin parachain (in the relay chain) to a holding state
  • Buy execution: buys execution time from the relay chain, to execute the XCM message
  • Transact: provides the call data to be executed
  • Deposit asset (optional): refunds the leftover funds after the execution. If this is not provided, no refunds will be carried out
2 Likes

More use cases !!!