Method and apparatus for discovering network service providers

The invention discloses a method and a corresponding device for realizing NSP discovery. The method transmits the NSP information supported by the current NAP at the network side, and transmits the NSP first change information supported by the currently active NAP at the same time on the network side, When the terminal device is connected to the network, obtains the first change information of the NSP supported by the NAP which can be accessed by the current location fixed by the network side; determines whether the first change information coincides with the NSP change information supported by the stored NAP, If the judgment is yes, the stored NAP access NSP information is acquired, otherwise the NAP information of the NAP which is sent by the network side is acquired, and the acquired NSP information is added as the available NSP information. The invention can reduce the extra occupation of the empty port resources and effectively reduce the time consumption in the network discovery and selection process. Enabling the terminal to track updates of NSP information supported on the NAP in a timely manner.