What were the causes and impact of increase Indian ocean trade in the postclassical era?

The number of civilizations participating increased as well as trade networks developed.

Explanation:

There are many reasons for the springing up of Indian ocean trade, this includes:

new kingdoms in South east Asia and middle eastByzantines consolidating power while the Europeans dwindledIndian trade becoming more fruitful with spicesThe advent of Islamic trade routes

The impact of this was:

India became an epicenter of trade along with Arabia due to the expansive sea routes.The spread of Islam to other coasts was quicker.