User's Manual

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Chapter 3 System Structure

LTE eNB System Description v2.0 40

 IPSS: Software that performs the security functions for the IP layer. It is

responsible for filtering based on the IP address, TCP/UDP port number, and

protocol type.

 DHCP: Software block that performs the automatic IP address allocation

function. It is responsible for obtaining an IP address automatically by

communicating with DHCP server.

In the following sections, the Master OAM Board and Call Processing Board,

where the software runs on, indicate LMD1 and RFD01P-13A of CDU each.

CPS Block

The Call Processing Software (CPS) block performs resource management of LTE

eNB and call processing function in eNB, which is defined in the 3GPP. Also, CPS

performs the interface function with EPC, UE, and neighbor eNBs. The CPS

consists of eNB control processing subsystem (ECS), which is responsible for

network access and call control functions, and eNB data processing subsystem

(EDS), which is responsible for user traffic handling.

In addition, depending on eNB functions defined in 3GPP, ECS consists of SCTB,

ECMB, ECCB, SCTB, CSAB, TrM, and EMCB. Also, EDS consists of GTPB,

PDCB, RLCB, and MACB.

The following figure shows the CPS structure:

Figure 22. CPS Structure

Stream Control Transmission protocol Block (SCTB)

The SCTB is responsible for establishing S1 interface between eNB and MME,

and establishes X2 interface between neighbor eNBs. It operates on the master

OAM board.

The major functions of SCTB are as follows:

 S1 interfacing