Emulex DCP_link - Manual (Page 95)

7-2 Chapter 7
Introduction
Emulex X.25 software operates in a NetWare server or NetWare
router/bridge PC environment and provides services for NetWare products
and other applications (including independent developer applications)
requiring wide area connectivity
Emulex X.25 uses the 1984 CCITT X.25 Recommendation, which defines
the interaction between data terminal equipment (DTE) and data circuit-
terminating equipment (DCE) of a packet-switching network.
In general the end user equipment (mainframe, pad, server) is DTE and the
service provider (X.25) is DCE. In the illustration we see an example of a
call established between two DTE connections.
X.25 DTE DTE DCE DCE
IBM Compatible Novell Server
DTE and DCE are both responsible for establishing, maintaining, and
terminating the connection. The X.25 protocol primarily services between a
DTE/DTE pair providing the DCE connection.
As described earlier the Emulex X.25 implements the 1984 CCITT X.25
recommendations, including the level 1 (physical), level 2 (frame), and level
3 (packet), along with several library modules. All three levels are generally
configured as either DTE or all three as DCE though exceptions can occur.
For example a DCE which accepts clock signals from a modem would have
level 1 configured as DTE ( interface speed set to external).
Emulex X.25 interface runs in conjunction with NetWare MultiProtocol
Router 3.0 and supports a wide variety of other proprietary software
platforms.