In LTE architecture, core network includes Mobility Management Entity (MME), Serving Gateway  (SGW), Packet Data Network Gateway (PDN GW) where as E-UTRAN has E-UTRAN NodeB (eNB). With increased data rates, improved spectrum efficiency and packet-optimized system, LTE technology is set to drive machine to machine technology and data intensive applications.

In LTE architecture, core network includes Mobility Management Entity (MME), Serving Gateway  (SGW), Packet Data Network Gateway (PDN GW) where as E-UTRAN has E-UTRAN NodeB (eNB). With increased data rates, improved spectrum efficiency and packet-optimized system, LTE technology is set to drive machine to machine technology and data intensive applications.

The figures shown below provide mapping of protocols to corresponding  specifications. To find 3GPP LTE specification, click at the corresponding protocol in the images below.

Protocol structure of control plane in between UE & MME is shown below. 

This figure below shows protocol structure in between UE & P-GW user plane. GPRS Tunnelling Protocol for the user plane (GTP-U) tunnels user data between eNodeB and the S-GW as well as between the S-GW and the P-GW in the backbone network. 

The X2 interface is defined between two neighbour eNBs. This figure below shows the control & user plane protocol stack of the X2 interface.

To know more about LTE architecture & node details see LTE WiKi.