ICS20 v2 Support for path forwarding

[crodriguezvega]

Special thanks to the Strangelove Ventures team for developing packet forward middleware, which serves as a precursor to this feature.

Problems

ICS20 v1 presents a number of challenges:

• Fungibility of tokens depends on the path that tokens have travelled. For example: given 3 chains (A, B and C), chain A native tokens sent to chain B and then to chain C will not be fungible with chain A native tokens directly sent to chain C
• Poor user experience for transferring tokens through multiple hops: if a user wants to transfer tokens between chains, the user needs to sign each transaction on every chain and wait for the tokens to arrive at the destination before performing an action with them

Goals

With ICS20 v2 we intend to achieve the following goals:

• To allow end users to automatically and atomically unwind fungible tokens to their originating chain (regardless of the number of intermediary chains).
• To allow end users to automatically and atomically forward fungible tokens to a destination chain (regardless of the number of intermediary chains that there may be between the sending and destination chain).
• To allow end users to combine the both actions above, so that end users can unwind fungible tokens and automatically and atomically forward them to a destination chain (so that, for example, tokens arrive at the destination chain with only 1 hop in the path).

Resources

• Spec changes.
• Requirements.
• Alpha milestone.

[DimitrisJim]

can we close issue now?

[crodriguezvega]

Considering that we still have a few issues in the RC milestone I think it's ok to still keep it open.