Section: 7.7.3 GTP Message of Invalid Length
Content: If a GTP entity receives a message, which is too short to contain the respective GTPv2 header, the GTP-PDU shall be silently discarded. Apart from a piggybacked GTP message or an Echo Request message, if a GTP entity receives a Request message within an IP/UDP packet of a length that is inconsistent with the value specified in the Length field of the GTP header, then the receiving GTP entity should log the error and shall send the Response message with Cause IE value set to "Invalid Length". Apart from a piggybacked GTP message, if a GTP entity receives a Response message within an IP/UDP packet of a length that is inconsistent with the value specified in the Length field of the GTP header, then the receiving GTP entity should log the error and shall silently discard the message. If a GTP entity receives two GTP messages (triggered response message and a piggybacked initial message) within an IP/UDP packet of a length that is inconsistent with the total length of the two concatenated messages as indicated by Length fields of the GTP headers, then the receiving GTP entity should log the error and return an appropriate Response message with Cause IE value set to "Invalid overall length of the triggered response message and a piggybacked initial message". That is: - for a Create Session Response message together with a piggybacked Create Bearer Request message, a Create Bearer Response message should be returned with the above Cause value. - for a Create Bearer Response message together with a piggybacked Modify Bearer Request message, a Modify Bearer Response message should be returned with the above Cause value.