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ITU-T X.25 Protocol Module - C Source Library HsX25 1.2
with RFC1613 Cisco mode XOT for X.25 over IP applications

overview

HS X.25 is a software library in C (supplied with full source code) which implements ITU-T recommendation X.25 - Interface between Data Terminal Equipment (DTE) and Data Circuit-terminating Equipment (DCE) for terminals operating in the packet mode and connected to public data networks by dedicated circuit and RFC1613 Cisco Systems X.25 over TCP (XOT)

HS X25 Architecture

Release Notes

Version 1.2
- base tested full release

Version 1.2.1
- fixed handle leak in socket layer when closing and de-initialising the library

Current Customers

 ▪ SITA (Canada)
 ▪ Servebase (UK)
 ▪ Express Online (Russia)
 ▪ Union Pacific Railroad (USA)
 ▪ Topsonic (Germany)
 ▪ ASIQ (Australia)
 ▪ NICE Systems Ltd (Israel)

FEATURE TABLE

how it works

When user application initlialises Hs X.25 library, it provides interface callbacks for the services used by HS X.25 protocol module: timer management, and event callbacks.

The application then calls HsX25 functions to establish virtual circuits, send and receive data, enforce flow control and clear calls.

HS X.25 internally at a lower layer interfaces to HsDL library. HsDL library is Data Link layer abstraction, which includes RFC1613 Cisco mode XOT (X.25 over TCP) sub-module. When HS X.25 is ported into environment with LAPB or LAPD as data link layer, only HsDL module needs to change.

HsDL links directly to HsSock module (also included in this package) - Winsock interface component that provides reliable TCP transport services similar to LAPB / LAPD / HDLC.

HsX25 as provided to customer may be used immediately in X.25 over TCP (Cisco XOT) solution or it may be used with traditional LAPB or LAPD in which case only HsDL will need to be modified.