what's the difference on CRDs between Erie Canal and MCS API?

[addozhang]

Please describe what should be documented
It's described that Erie Canal is an implementation of MCS API, but it uses CRDs from a different group.

Could you figure out their difference and where it comes from?
Please suggest where in the repo the document should be located

[reaver-flomesh]

ServiceExport

ServiceImport

[addozhang]

Thanks @reaver-flomesh .