Method for obtaining internet protocol header replacement mapping and network node

A communication method, comprising: obtaining (201, 301, 701), by a network node of a user equipment, UE, a fixed part of an Internet Protocol header, IP, which is bound to the UE, in wherein the network node comprises a mobility management entity or a packet data network gateway; establish (202, 302, 702), by the network node, an IP header replacement mapping according to the fixed part of the IP header, where the IP header replacement mapping is a mapping between the fixed part sets of the IP header and an index; performing (203, 303, 703), by the network node, a data transmission with the UE according to the IP header replacement mapping.