T-PDU is Transport -PDU. It is the actual IP data gram that is sent by UE. It is tunneled through using the GTP protocol through the S1-U and S5/S8 interface. P-GW retrieves the IP datagram and sends to destination.
T-PDU means Transport PDU which means only applicable to GTP-U. GTP-U carries the encapsulated PDU from SGW to PGW or eNodeB to SGW or vice-versa.
Implementation of user plane processing at the user space of node is time consuming and cpu intensive. Is there any library/solution available through which GTP encapsulation/de-capsulation can be done at kernel level to reduce delay ?