Would "porting" Whatsapp mean that the end result would be able to communicate with users using Whatsapp on Android, or would it just be Whatsapp on an entirely

Would "porting" Whatsapp mean that the end result would be able to communicate with users using Whatsapp on Android, or would it just be Whatsapp on an entirely separate network, like Signal? The former is a lot more valuable to me than the latter.