HP DECnet-Plus for OpenVMS Alpha and OpenVMS I64, Version 8.3

ManualsBrandsHP ManualsSoftwareOpenVMS 8.4

HP DECnet-Plus for OpenVMS Alpha and OpenVMS I64, Version 8.3 SPD 50.45.19

The optional X.25 for OpenVMS software allows HP

DECnet-Plus for OpenVMS systems to connect to PS-

DNs (packet switching data networks) conforming to

CCITT Recommendation X.25 (1980 or 1984) and/or

ISO 7776 and 8208, or through an X.25 relay system

directly connected to a PSDN, or through an X.25 con-

nector node (X.25 gateway), or over TCP/IP using RFC

1613 (XOT). The software allows process-to-process

as well as terminal-to-process communications between

Alpha systems and remote DTE (data terminal equip-

ment) over a PSDN.

The X.25 software provides the Connection-Oriented

Network Service (CONS) to allow mapping between a

destination NSAP address and a destination DTE ad-

dress according to ISO 8348.

Direct access to a PSDN (using the supported device

drivers) requires an X.25 license. See the Optional Soft-

ware section.

For more details on the X.25 software for OpenVMS,

refer to the X.25 for OpenVMS Alpha and Integrity sys-

tems Software Product Description (SPD 47.37.xx).

Network Layer

HP DECnet-Plus for OpenVMS supports the

Connectionless-Mode Network Service (CLNS) and the

Connection-Oriented Network Service (CONS).

Exchange of routing information between end systems

and routers uses the ISO 9542 ES-IS routing proto-

col. This protocol allows DECnet-Plus systems to au-

toconﬁgure as end systems with ISO 9542-conformant

routers.

Addresses conform to the ISO 8348 Addendum 2 spec-

iﬁcation, allowing the support of large network topolo-

gies. As long as the system address stays within the

addressing range of Phase IV systems (up to 1,023 sys-

tems per area and up to 63 areas per network), and uses

the same initial domain part (IDP), you can use Phase

IV or Phase V routers.

The Network layer supports the capability of an end

system to be multicircuited and multihomed. Multicir-

cuit support allows multiple circuits to be active simulta-

neously. This functionality increases network reliability

and data throughput. Multihomed end-system support

allows a system to have up to three network entity titles.

Segregated routing mode is a settable attribute. It di-

rects routing to choose a Phase IV router for those pack-

ets having a destination address that can be translated

to the Phase IV format. All other packets are sent to a

Phase V router, if available.

The Routing layer is able to cache information about the

paths that are used to reach remote nodes.

Transport Layer

HP DECnet-Plus for OpenVMS provides support for:

• OSI Transport protocol as speciﬁed in ISO 8073

• RFC 1006 and RFC 1859 to allow OSI and DECnet

applications to run over TCP/IP

• Network Services Protocol (NSP)

NSP, RFC 1006, and OSI transports support commu-

nications between DECnet, TCP/IP, and OSI systems.

NSP provides backward compatibility with Phase IV

DECnet systems.

RFC 1859 support for DECnet applications is pro-

vided by a kernel interface that is implemented on all

TCP/IP stacks available for use on the OpenVMS op-

erating system. The supported applications include all

licensed DECnet applications as well as layered prod-

ucts and user-written applications that conform to the

documented DECnet programming interfaces.

RFC 1006 is a speciﬁcation for running OSI applications

over TCP/IP. Operation of the FTAM and Virtual Terminal

application over a TCP/IP network is supported along

with other layered OSI applications such as X.400 and

X.500.

A separate TCP/IP stack is required on the same system

with DECnet-Plus. See the Optional Software section of

this SPD for information on supported TCP/IP products.

OSI transport supports transport classes 0, 2, and 4 on

connection-oriented networks and class 4 on connec-

tionless networks.

OSI transport uses two types of network service:

• The Connectionless-Mode Network Service (CLNS)

using the Internet protocol (ISO 8473) and ES-IS pro-

tocol (ISO 9542) to communicate across linked sub-

networks.

• The Connection-Oriented Network Service (CONS).

Upper Layers

HP DECnet-Plus for OpenVMS software provides the

OSI upper layer stack consisting of Session, Presenta-

tion and Application layers. The Application layer pro-

vides Association Control Service Element (ACSE); File

Transfer, Management, and Access (FTAM); and Virtual

Terminal (VT).

HP DECnet-Plus for OpenVMS also provides a range

of DECnet applications and services including ﬁle and

record access, remote terminal access, mail, and

phone.