The theory behind this speaks to the Islamic State strategy. The networks — "three in Libya, two in Saudi Arabia, and one each in Sinai, Nigeria, Yemen, Algeria, and Khorasan in Pakistan and Afghanistan" — are seen as liaisons that won't easily become lost or overtaken by other forces, according to the Soufan Group.
One of the most notable terrorist groups recently connected to the Islamic State is the Nigeria-based Boko Haram. After carrying out attacks that left at least 50 people dead in March, the leader of Boko Haram announced its alliance with the Islamic State.
Although Islamic State jihadists are hesitant to forge ties with other groups, they are quick to take credit for many of the high-profile attacks that have happened as of late, even if they don't have a network in those regions, including the Texas shootings, Charlie Hebdo massacre and the attacks in Tunisia.
Within Syria and Iraq, the militants have established 20 different "states." Unlike most of the 10 "wilayats," or states listed above, the Islamic State controls land and has tried to create a government in most of these cities. Note that recent victories over cities like Ramadi aren't included yet as there hasn't been a formal declaration of a state, yet.
Compare the Islamic State's growing network to the once reigning terrorist group al-Qaeda. Deeming the Islamic State's practices too radical, al-Qaeda severed ties with the militants more than a year ago.