HP X.25 for OpenVMS Alpha and I64 Systems, V2.0

HP X.25 for OpenVMS Alpha and I64 Systems, V2.0 SPD 47.37.16
HP X.25 for OpenVMS supports the following functions:
• Process–to–process (HP X.25) communication.
X.25 for OpenVMS allows application programs to
access X.25 network services via the standard
OpenVMS QIO system service.
• Process–to–terminal (X.29) communication.
Through the X.29 QIO programming interface, users
of the OpenVMS system may make outgoing calls
to other HP or non–HP systems or suitable network
PADs accessible via a PSDN.
• Terminal–to–process (X.29) communication.
Remote terminals connected to the PSDN may ac-
cess the OpenVMS host running X.25 by means of
an X.29 Switched Virtual Circuit (SVC) call.
• DECnet-Plus Connectionless Network Service.
The product supports the use of the DEC–HDLC
and X.25 protocols as sub–networks for the OSI
Connectionless–mode Network Service (CLNS).
• DECnet-Plus Connection Oriented Network Service.
The product supports the OSI Connection Oriented
Network Service (CONS) for OSI Transport over X.25
sub–networks.
• X.25 Mail.
The X.25 Mail utility allows communication across a
PSDN via electronic mail between two systems run-
ning the Mail–11 protocol over X.25. Systems that
support Mail–11 over X.25 include WAN Support for
HP UNIX®, X.25 for OpenVMS and X.25 installations
of DECnet-Plus for OpenVMS VAX.
• Wide Area Network (WAN) Device Drivers
The WAN device drivers support synchronous com-
munications and offer a supported user ($QIO) in-
terface. This version also includes a pseudodriver
(WANDRIVER) that provides a programming inter-
face to the Data Link level for the LAPB, DEC-HDLC,
and LLC2 protocols and an interface to the physi-
cal layer of the synchronous communication devices
supported by the product.
Note: This function is not applicable for X.25 for
OpenVMS I64.
• X.25 Relay allows an appropriately configured Open-
VMS system to relay X.25 packets between a Lo-
cal Area Network (LAN) and a synchronous com-
munications link to a Packet Switched Data Network
(PSDN).
• X.25 GAP Server allows remote Phase V GAP clients
to connect to a PSDN via the GAP Server node using
the DECnet NSP protocol. The remote X.25 client (or
access node) communicates with the X.25 Server or
X.25 Gateway/Connector node using the Gateway
Access Protocol (GAP) via a DECnet session con-
nection.
• The multi-host mode of operation provides the fea-
tures offered by VAX P.S.I. Native and also allows
VAX P.S.I. Access systems to connect to a PSDN as
though directly connected.
• XOT or X.25 over TCP/IP allows X.25 applications
on an appropriately configured OpenVMS System to
communicate with other RFC 1613 implementations
over a TCP/IP Wide Area Network.
Features
Conformance to Standards
HP X.25 for OpenVMS complies with the following stan-
dards:
• ITU/TSS recommendations—X.25 (1980, 1984, or
1988), X.3, X28, X.29
• International standards ISO—8208, 7776, 8881,
8802/2, 8878, 8473
Virtual Circuits
HP X.25 for OpenVMS offers communication over both
Permanent Virtual Circuits (PVCs) and Switched Virtual
Circuits (SVCs), and supports up to 4096 virtual circuits
per system. One virtual circuit is used for each incom-
ing or outgoing X.29 terminal connection, for each X.25
call, and for each DECnet-Plus routing circuit and trans-
port connection. The use of PVCs for X.29 communi-
cation is not defined by the 1980 and 1984 ITU/TSS
recommendations, and is not available with HP X.25
for OpenVMS.
Virtual circuits may use X.25 protocol over a LAN con-
nection, over a WAN synchronous communications con-
nection, or may use HP X.25 Client for OpenVMS Al-
pha Systems over a DECnet circuit to a DECnet Gate-
way Access Protocol (GAP) connector node. NOTE that
there is no support for use of more than 512 of the avail-
able virtual circuits by HP X.25 Client for OpenVMS
Alpha Systems with DECnet Gateway Access proto-
col connector nodes. See the HARDWARE REQUIRE-
MENTS section for details of GAP connector nodes and
ISO relay nodes supported.
Process–to–Process Communication
The HP X.25 for OpenVMS programming interface al-
lows application programs to access X.25 packet level
services via the standard OpenVMS QIO interface.
Functions include the establishment and clearing of
network connections, data transmission and reception,
sending and receiving of interrupt messages, and reset-
ting of virtual circuits. The interface also provides for the
segmentation and recombination of messages that are
longer than the packet size selected for the circuit.
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