The building blocks would be divided by the BOCs as follows: Basic Service Elements, Basic Serving Arrangements, Complimentary Network Services, and Ancillary Network Services.
BBC World Service | National Park Service | Internal Revenue Service | Distinguished Service Order | Special Air Service | United Parcel Service | Meritorious Service Medal (United States) | United States Postal Service | National Health Service | Meritorious Service Medal | Metropolitan Police Service | United States Forest Service | German Academic Exchange Service | Secret Intelligence Service | BASIC | Immigration and Naturalization Service | Distinguished Service Cross | National Defense Service Medal | National Service | United States Secret Service | Royal Naval Air Service | National Weather Service | Agricultural Research Service | Special Broadcasting Service | Distinguished Service Cross (United States) | Visual Basic | On Her Majesty's Secret Service (film) | On Her Majesty's Secret Service | Internet service provider | Chemical element |