If one is curious about trade and travel routes in the Islamic world in the 14th Century CE, there are many great maps in Dunn's book, The Adventures of Ibn Battuta.
Battuta travelled between Yemen and East Africa, and much later, by camel caravan from Tunisia into the Sahel, hence to Mali and back.
He also went through Anatolia, Mesopotamia, the steppes, Afghanistan, Sindh, and lived in India.
Dunn gives maps for Battuta's various itineraries, describing the modes of transport and times needed.
There is no information given about travel across central Africa between the East and Mali, as Battuta did not take that route.
http://www.google.com/search?q=dunn+...-1&btnG=Search
But one can get an idea of how very many travel routes existed throughout Dal al Islam, for trade and for making the Haj.
Blades and technicians would have circulated far and wide.
One very great discovery was managing boat traffic across the Indian ocean by exploiting the monsoon patterns. India, Muskat/Oman, Yemen/Hadramaut and Mogodishu and surrounding ports would have been well connected.
Even though Dunn offers an overview, his book is very readable and the maps are a big help.