Section: 8.22 Fully Qualified TEID (F-TEID)
Content: Fully Qualified Tunnel Endpoint Identifier (F-TEID) is coded as depicted in Figure 8.22-1. Figure 8.22-1: Fully Qualified Tunnel Endpoint Identifier (F-TEID) The following flags are coded within Octet 5: - Bit 8 – V4: If this bit is set to "1", then IPv4 address field exists in the F-TEID, otherwise the IPv4 address field is not present at all. - Bit 7 – V6: If this bit is set to "1", then IPv6 address field exists in the F-TEID, otherwise the IPv6 address field is not present at all. At least one of V4 and V6 shall be set to "1", and both may be set to "1". - Bit 6 to Bit 1 – Interface Type: This 6 bit wide integer can take the following values representing interface type and endpoint: 0: S1-U eNodeB GTP-U interface 1: S1-U SGW GTP-U interface 2: S12 RNC GTP-U interface 3: S12 SGW GTP-U interface 4: S5/S8 SGW GTP-U interface 5: S5/S8 PGW GTP-U interface 6: S5/S8 SGW GTP-C interface 7: S5/S8 PGW GTP-C interface 8: S5/S8 SGW PMIPv6 interface (the 32 bit GRE key is encoded in 32 bit TEID field) 9: S5/S8 PGW PMIPv6 interface (the 32 bit GRE key is encoded in the 32 bit TEID field, see clause 6.3 in 3GPP TS 29.275[ Proxy Mobile IPv6 (PMIPv6) based Mobility and Tunnelling protocols; Stage 3 ]  [26]) 10: S11 MME GTP-C interface 11: S11/S4 SGW GTP-C interface 12: S10/N26 MME GTP-C interface 13: S3 MME GTP-C interface 14: S3 SGSN GTP-C interface 15: S4 SGSN GTP-U interface 16: S4 SGW GTP-U interface 17: S4 SGSN GTP-C interface 18: S16 SGSN GTP-C interface 19: eNodeB/gNodeB GTP-U interface for DL data forwarding 20: eNodeB GTP-U interface for UL data forwarding 21: RNC GTP-U interface for data forwarding 22: SGSN GTP-U interface for data forwarding 23: SGW/UPF GTP-U interface for DL data forwarding 24: Sm MBMS GW GTP-C interface 25: Sn MBMS GW GTP-C interface 26: Sm MME GTP-C interface 27: Sn SGSN GTP-C interface 28: SGW GTP-U interface for UL data forwarding 29: Sn SGSN GTP-U interface 30: S2b ePDG GTP-C interface 31: S2b-U ePDG GTP-U interface 32: S2b PGW GTP-C interface 33: S2b-U PGW GTP-U interface 34: S2a TWAN GTP-U interface 35: S2a TWAN GTP-C interface 36: S2a PGW GTP-C interface 37: S2a PGW GTP-U interface 38: S11 MME GTP-U interface 39: S11 SGW GTP-U interface 40: N26 AMF GTP-C interface 41: N19mb UPF GTP-U interface Other values of "Interface Type" are spare and reserved for future use. "Interface type" values with bit "6" set to 1 shall only be used between Rel-10 onwards GTPv2-C nodes. NOTE 1: "Interface type" IE is defined with 5 bits only in the earlier releases of this specification, thus pre-Rel-10 GTPv2-C nodes can ignore bit "6" which is marked as "Spare" in earlier releases, allowing backward compatibility. NOTE 2: Interface Type 8 is not used in this Release and in earlier Releases. Octet 6 to 9 (TEID/GRE field) represent either a TEID or a GRE key. If both IPv4 and IPv6 addresses are present in F-TEID IE, then the TEID value shall be shared by both addresses. Octets "m to (m+3)" and/or "p to (p+15)" (IPv4 address / IPv6 address fields), if present, contain respective address values.