Impression of an Indus-style cylinder seal of unknown Near Eastern origin in the Musee du Louvre, Paris. All indications are that the Bronze age was built on a robust international trade system. Massimo Vidale's article Growing in a Foreign World: For a History of the "Meluha Villages" in Mesopotamia in the 3rd Millenium BCE gathers together all facts about Indus settlements and trading with ancient Mesopotamia around 2500 BCE. Conjectures and implications by an Italian archaeologist who is a pioneer in multidisciplinary analysis. The connections between these ancient Bronze age civilizations could one day help answer a lot of questions. People moved around a lot more than we think, and interactions between cultures just as rich as they are today.
For more, read Growing in a Foreign World: For a History of the "Meluha Villages" in Mesopotamia in the 3rd Millenium BC.