IBM AS/400 manual Wide area network standards, Asynchronous communications, Frame relay networks

the AS/400 wireless LAN adapter and remote stations. Remote stations can be PTCs that are running

5250 emulation or LAN-connected systems that are equipped with compatible wireless adapters. There are other implementations of wireless LAN.

Wide area network standards

A wide area network (WAN) is a data communications network designed to serve an area of hundreds or thousands of miles--for example, public and private packet-switching networks, and national telephone networks.

These topics introduce the types of wide area networks that are supported by the AS/400 system:

vAsynchronous communications

vBinary synchronous communications

vFrame relay

vIntegrated services digital network

vSynchronous data link control network

vX.25 network

vX.21 network

Asynchronous communications

OS/400 asynchronous communications support allows an AS/400 application program to exchange data with a remote system or device using either an asynchronous (start-stop) or X.25 line. AS/400 application programs can be written in ILE COBOL/400, ILE RPG/400, ILE C/400, or FORTRAN/400 languages. Asynchronous communications support includes file transfer support (also used with other communications types) and interactive terminal facility (ITF). Asynchronous communications support provides program-to-program and program-to-device communications between systems that use asynchronous (start-stop) or X.25 lines. For X.25 lines, it also supplies an integrated packet assembler/disassembler (PAD) (1) that follows CCITT recommendations X.3, X.28, and X.29.

Asynchronous communications support allows you to send data to and receive data from a remote program or device attached by either an asynchronous (start-stop) or an X.25 line. Your application program must provide the data stream required by the remote device. Asynchronous communications support packages your data stream in either a start-stop format or within X.25 data packets.

Binary synchronous communications

(BSC) is a data communications line protocol that uses a standard set of transmission control characters and control character sequences to send binary-coded data over a communications line. Binary synchronous communications equivalence link (BSCEL) support is the intersystem communications function (ICF) support on the AS/400 system that provides binary synchronous communications with a remote system or device. BSCEL also supplies online and batch communications between application programs on different BSC systems. AS/400 application programs can be written in the Integrated Language Environment (ILE) C/400*, ILE COBOL/400*, ILE FORTRAN/400*, or ILE RPG/400* programming languages.

Frame relay networks

Frame relay is a protocol that defines how frames are routed through a fast-packet network based on the address field in the frame. Frame relay takes advantage of the reliability of data communications networks to minimize the error checking done by the network nodes. This provides a packet-switching protocol similar to, but much faster than, X.25. The high speed that can be obtained through frame-relay networks makes it well suited for wide area network (WAN) connectivity. Frame relay is commonly used to connect two or more LAN bridges over large distances.

The AS/400 system supports these frame-relay network connections:

Chapter 10. Common networking standards 93