If you stick to a networking example, the central is the socket that starts the connection and the peripheral is the listening socket. Only a server socket and and a client socket can communicate with each other. Consequently,
there exist only central-peripheral connections.
But the central and the peripheral roles can happily live together in the same device. (You can open listening and connecting sockets on the same device.) Your peripheral (be it an iOS device or anything else) can be a peripheral that exposes services and central that connects to other peripherals.
Most of the confusion comes from the unfortunate naming scheme. The BLE peripheral could have been Server and the BLE central could have been Client. The peripheral word is overloaded with the role and the device meanings that makes things hard to reason about for people with little or no BLE knowledge.