Carriers price DS1 lines in many different ways. However, most boil down to two simple components: local loop (the cost the local incumbent charges to transport the signal from the end user's central office, otherwise known as a CO, to the point of presence, otherwise known as a POP, of the carrier) and the port (the cost to access the telephone network or the Internet through the carrier's network). Typically, the port price is based upon access speed and yearly commitment level while the loop is based on geography. The farther the CO and POP, the more the loop costs.