ss to a network's services on a wholesale basis means that the network's elements are kept together, but that competitors are allowed to purchase and then resell the services provided by the entire network to final customers. Because wholesale access utilizes the entire network in largely the same manner as the network owner, the ability of the network to operate is less likely to be affected than in the case of access to only a portion of the network. The main things that are affected would appear to be the merchant activities of the network owner. The wholesale provision of network services simply removes some of the retail activities of the network operator and replaces those activities with wholesale activities. These activities are more a matter of transaction costs, including the costs of back office activities, marketing, and sales. 3. Interconnection Access Interconnection access refers to any reciprocal interconnection agreements between networks. Most networks in a given industry are interconnected. For example, prac- tically all telecommunications networks are either directly or indirectly connected, SO that a telephone call originating from any wireless or wireline telecommunica- tions system can reach anyone on any other system around the world. Intercon- nection is reciprocal because communication of this type is a two-way street, with each network both originating and terminating telephone calls. The Internet is a network of networks with reciprocal arrangements. Packets of data from a given communication are split up and travel separately across multiple networks. Whole- sale electric power transmission grids often comprise multiple interconnected net- works. Transportation networks, such as railroads, are often interconnected SO that trains can travel across multiple networks. Some connections are internal to the network, whereas others are external to it. The nodes and links that form networks generally are physical facilities, such as switches and lines in a telecommunications system. In our di