You need Axum (Acksum, ethiopia) (frequently said to be on par with persia by the persians during that period, went christian in the 2nd century) to facilitate trade between The Empire and the equivalent of india, it had the occasional problem that some of its naval forces would sometimes go pirate and attempt to steal whole cities, and Axum also acted as a temporary host for muhammed, who would operate a kaliphate in exile during that period before he took medina and mecca.