A communication method comprises that if a policy control device does not support setup of an Internet Protocol (IP) multimedia subsystem (IMS) default bearer during setup of an IMS default bearer for a terminal, the control plane gateway sends second indication information to a user plane gateway, where the second indication information indicates the control plane gateway bypasses the policy control device. When the user plane gateway receives an IMS session request from the terminal and determines that the control plane gateway bypasses the policy control device, the user plane gateway sends first indication information to the control plane gateway, and the first indication information indicates the control plane gateway to send, to the policy control device, a first request to request to establish a mapping relationship between the terminal and the control plane gateway such that an IMS session can be set up between terminals.