The "Service name" field is visible when you click the Internet tab in the AirPort Admin Utility and set the "Connect using" pop-up menu to "PPP over Ethernet (PPPoE)."
Figure 1 The Service name field
Like the DHCP Client ID used on many networks, the service name is an optional piece of information that Internet service providers may choose to use to control access. When a service name is used, the Internet service provider defines the types of service to which the service name controls access. Most Internet service providers do not require the use of a service name. You should not type anything into this field unless instructed to do so by your Internet service provider. Contact your Internet service provider for any questions about the use of service names on its network.
Note: Wireless Internet access requires an Internet service provider (fees may apply) and AirPort (or AirPort-compatible) wireless Ethernet card and base station. Some ISPs are not compatible with AirPort. For more information, see technical document 106590: "AirPort: Requirements for Wireless Internet Access".
Figure 1 The Service name field
Like the DHCP Client ID used on many networks, the service name is an optional piece of information that Internet service providers may choose to use to control access. When a service name is used, the Internet service provider defines the types of service to which the service name controls access. Most Internet service providers do not require the use of a service name. You should not type anything into this field unless instructed to do so by your Internet service provider. Contact your Internet service provider for any questions about the use of service names on its network.
Note: Wireless Internet access requires an Internet service provider (fees may apply) and AirPort (or AirPort-compatible) wireless Ethernet card and base station. Some ISPs are not compatible with AirPort. For more information, see technical document 106590: "AirPort: Requirements for Wireless Internet Access".