Movement of goods, peoples & culture has been very old in Indian Ocean sub continents with the Indian Ocean playing the crucial role. There are many archeological and other proofs of these interactions. The interactions can be understood as within sub continents & with Inter subcontinent.
Interaction of Peoples with in Indian Subcontinent
During the Iron Age, two major highways connected the subcontinent. Uttra Path is the first one and is an east west road which ran from eastern Afghanistan, across the gangetic plains to ports of Bengal. Today this road is famous for national highway 1 between Amritsar & Delhi and as national highway 2 between Delhi & Kolkata. The second was Dakshina path and was a north south highway. It started around the Allahabad-Varanasi section of Gangetic plains and made its way to a south westerly direction to Ujjain. Here it splits into two with one branch going to ports of Gujarat & second branch making its way further south via Partisthana to Kishikanda in Karnataka & beyond. People’s cultures had moved along these highways. Many of events described in epics took place along them.