Of all cargo that flows into Afghanistan, about half (50%) transits Pakistan. There are two main border crossings between Pakistan and Afghanistan, Chaman gate and Torkham gate.
About 30 percent of all cargo flows into Afghanistan via the Northern Distribution Network (NDN) and transits Kazakhstan and Uzbekistan. There are two major routes on the NDN, one through Russia and the other through the Caucasus. The NDN is used to bring commercial-type cargo (sustainment items like food and spare parts) to U.S. troops serving in Afghanistan.
The NDN does not replace routes through Pakistan, but provides additional transportation options for General Mattis and General Petraeus, and helps prevent any specific route from becoming a single point-of-failure for Operation Enduring Freedom logistics.
The remaining 20 percent of cargo is brought into Afghanistan by air. Most of this cargo is sensitive, which includes such things as weapons, ammunition and critical equipment.
Source: Department of Defense