ATM Connecting Mode

ATMs located in different remote areas are connected to a Central Computer of the respective Bank in following two different modes.

• Direct Connecting Mode
• Front End Processor Mode

 In this chapter, you can know about network architectures of two connecting modes and their implementations.

Ø Direct Connection Mode

In the early days, ATM connects with the Central through direct connection, in which the application services and communication services are integrated in the Central, and ATM is directly connected with the Central environment.

The network architecture is shown in Figure 2-1:

Figure 3-1: Connecting by direct connection

Direct connection mode adopts SNA (Systems Network Architecture) at Central network and SDLC (Synchronized Data Link Control) protocol in network communications.

Ø Front End Processor Mode

Later to reduce the Central load, ATM connects with the Central in the front end processor mode, which means an equipment is set before the Central to specially forward data from ATM to the Central, thus to greatly save the Central resources and increase ATM access quantity. Currently this connecting mode is popular at the self-service equipment terminal of the bank. Its network architecture is shown in Figure 2-2.

Figure 3-2: Front end processor connecting mode

Ø Connecting Equipment

(1)      Central equipment

l     RS/6000 or HP

l     AS/400

l     S/390 or z/Series

l     Hardware Security Module(HSM): Used for data encryption.

(2)      Peripheral equipment

Ø    Disk system: IBM, EMC, HITACHI

Ø    Tape drive: 3480, 3490, 3590

Ø    Printer: IBM, Siemens

Ø    Tape library: IBM, STK

Ø    Communication equipment: 3745, CIP

Ø    Path connector: 9032, 2032

Ø    Terminal controller: 3174, 2074

Ø      Network Solution in the Direct Connection Mode

Since SDLC network communication protocol is adopted in direct connection, the synchronization communication card (SDLC emulation card) which supports the protocol is to be added at the terminal.

ATM can be connected with the Central by MODEM direct connection, PSDN (Public Switched Data Network) or DDN (Digital Data Network) private network, etc.

The network solution in direction connection mode is shown in Figure 3-3:

Figure 3-3: The connecting solution in direct connection mode

Ø   The Network Solution in FEP Mode

FEP means Front End Processor, it is also called Switching System.

In this mode, ATM is connected with LAN (Local Area Network) via the Ethernet card and then connected with the front end processor through DDN private network via routers. TCP/IP is mainly adopted as the network protocol.

ATM is connected with the front end processor via X.25 network with X.25 communication card, using X.25 as the network protocol.

ATM is connected with the front end processor through the serial port in SLIP access mode using DDN private network.

ATM is connected with the front end processor via wireless GPRS (General Packet Radio Service) network access, mainly using TCP/IP.

The Central environment of the bank is composed of the front end processor and the Central.

The network solution in the front end processor is shown in Figure 3-4.

Figure 3-4: The front end processor connecting solution

Ø   Switching and ATMC Systems

Switching system  is a communication pre-console between the host and ATM, mainly used for ATM equipment management, communication mode standardization (Internal access), transaction message format conversion, forwarding, etc. It is used for communication service.

ATMC (ATM Control)  system is the control system of the terminal equipment at the lowest level of ATM transaction channel. It runs on the terminal equipment (such as ATM) and is mainly used to provide the interactive interfaces of various transactions and management for the cardholder and ATM equipment administrator. It also fulfills specific functions through message interaction together with switching. It is used for ATM application service.

In the front end processor connecting mode, ATM sends data to the front end processor from its control system (ATMC) and the front end processor forwards data submitted by ATMC to the Central via switching. The returned command from the Central is sent to ATMC for ATM transaction.