A communication method performed by an access network device, the method comprising: receiving (S501) a radio access capability of a terminal device, wherein the received radio access capability is an ASN.1 encoded byte stream; detecting (S502) whether a target radio access capability the same as the received radio access capability of the terminal device exists in a terminal device access capability set, wherein the terminal device access capability set is a set of pieces of radio access capability information, each of the pieces including a respective radio access capability; and when the target radio access capability exists in the terminal device access capability set, introducing (S503) an access capability indication information into a context of the terminal device, wherein the access capability indication information is a radio access capability identifier and indicates the target radio access capability; characterized in that radio access capabilities stored in the terminal device access capability set are one of: ASN.1 encoded byte streams, or include both the ASN.1 encoded byte streams and the ASN.1 decoded radio access capabilities; wherein the detecting whether a target radio access capability the same as the received radio access capability of the terminal device exists in a terminal device access capability set comprises: determining, as the target radio access capability, a first access capability that has a byte stream the same as that of the received radio access capability of the terminal device and that is in the terminal device access capability set. receiving (S501) a radio access capability of a terminal device, wherein the received radio access capability is an ASN.1 encoded byte stream; detecting (S502) whether a target radio access capability the same as the received radio access capability of the terminal device exists in a terminal device access capability set, wherein the terminal device access capability set is a set of pieces of radio access capability information, each of the pieces including a respective radio access capability; and when the target radio access capability exists in the terminal device access capability set, introducing (S503) an access capability indication information into a context of the terminal device, wherein the access capability indication information is a radio access capability identifier and indicates the target radio access capability; characterized in that radio access capabilities stored in the terminal device access capability set are one of: ASN.1 encoded byte streams, or include both the ASN.1 encoded byte streams and the ASN.1 decoded radio access capabilities; wherein the detecting whether a target radio access capability the same as the received radio access capability of the terminal device exists in a terminal device access capability set comprises: determining, as the target radio access capability, a first access capability that has a byte stream the same as that of the received radio access capability of the terminal device and that is in the terminal device access capability set. ASN.1 encoded byte streams, or include both the ASN.1 encoded byte streams and the ASN.1 decoded radio access capabilities; wherein the detecting whether a target radio access capability the same as the received radio access capability of the terminal device exists in a terminal device access capability set comprises: determining, as the target radio access capability, a first access capability that has a byte stream the same as that of the received radio access capability of the terminal device and that is in the terminal device access capability set. <EOS>