P and PE routers will use IP routing protocol (Internal Gateway Protocol) to establish MPLS core network in the path, and the use of routers between the LDP to achieve the tag distribution.

• P与PE路由器将使用IP路由协议（内部网关协议）来建立MPLS核心网络中的路径，并且使用LDP实现路由器之间的标记分发。