Setting up an HRMP Channel between a Parachain and Rococo Asset Hub (Rockmine)

Question

I'm currently working on understanding the process for establishing an HRMP channel between a parachain and the [Rococo Asset Hub][1] (Rockmine).

I'm wondering whether a motion to the governance is required, similar to what would be done for Polkadot/Kusama, in order to initiate the HRMP channel. This would involve signing the polkadotXcm.send extrinsic containing the encoded call of hrmp.hrmpAcceptOpenChannel for incoming handshakes and hrmp.initOpenChannel for outgoing handshakes with root origin. Alternatively, is it necessary for someone with root access to perform this action on my behalf? I came across https://github.com/paritytech/subport for similar queries, but I'm uncertain if it's the appropriate resource to submit such an issue.

I attempted to find information about this question in the Polkadot Wiki, Substrate Wiki, and here, but unfortunately, I haven't come across anything relevant. In the event that there isn't existing documentation, I plan to open an issue in the Substrate docs repository, with the intention of eventually incorporating the provided guidance into the official documentation.

[1]: https://polkadot.js.org/apps/?rpc=wss%3A%2F%2Frococo-asset-hub-rpc.polkadot.io#/explorer](https://polkadot.js.org/apps/?rpc=wss%3A%2F%2Frococo-asset-hub-rpc.polkadot.io#/explorer

Answer 1

Check this tutorial about how to open HRMP with AssetHub, where it explains in detail how to opening the channel from AssetHub to your parachain and how to open the channel from your parachain to AssetHub.

If you still don't have slots in Rococo for your parachain, you can use as you indicate the url https://github.com/paritytech/subport to ask for it, and in the section Anything else we should know?, ask there to open a channel with Rockmine, see the example of a previous query.

It might be a good idea to open the issue in the Substrate Docs repository, is open for suggestions to improve the content.