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transport protocol data unit (TPDU): Unit of data,
processed by a transport protocol, with transport protocol control
information and, possibly, also user data.
transport selector: Field within the domain specific port (DSP) part of an NSAP that indicates to the Routing layer which transport is to receive the data. The selector value consists of two hexadecimal digits (from 0 to F). The DECnet-Plus values are 20 (for NSP transport) and 21 (for OSI transport).
Also called the NSAP selector.
Transport service: OSI service that provides a
universal communications interface that is independent of the low-level
communications medium and protocols; service to high-level protocols at
the upper boundary of the Transport layer, as defined in International
Standard ISO 8072.
transport service access point (TSAP): Unique
reference that identifies a transport user. When making a transport
connection, the transport user provides its TSAP. Messages sent over a
transport connection include the TSAP of the transport user to which
they are addressed. The transport service uses this TSAP information to
route messages to their proper destination. A transport user must be
associated with a TSAP in order to use the transport service.
transport service provider (transport service, TS
Provider): Software that provides a transport service.
Example: OSI transport.
transport service user (transport user, TS user):
Software running above the Transport layer and using the transport
service to communicate with other software running above the Transport
layer, possibly on another host.
transport subaddress: Subaddress that identifies the
transport service provider of an X.25 network; forms the last two
digits of a target system's X.25 destination address.
transport template: Entity that identifies the network
service to be used by an OSI transport connection, and the transport
characteristics that apply to that connection.
traversal sequence: Set of rules, defined by the FTAM
standard, for moving between nodes within a file, beginning with its
root node.
traversing: FTAM process of moving to the next node in
a sequence of nodes and, optionally, accessing information associated
with that node.
tributary: One of multiple points on a multipoint
line. See also polling.
tributary address: Address that a control station uses
to poll a tributary. See also polling.
tributary station: Station on a multipoint line that
is not a control station.
true name: Name of an entity that can be directly
mapped in the namespace (without resorting to backtranslation or soft
links) to an agent address.
TSAP: See transport service access
point.
TT Device: Device that processes system services
relating to user data, which are issued by the X.29 program, and passes
them to the NV device.
UA (User Agent): OSI application process that
represents a human user or organization in the X.400 message handling
system. Creates, submits, and takes delivery of messages on the user's
behalf.
UDP (User Datagram Protocol): TCP/IP transport
protocol; a connectionless transport protocol required by RIP and SNMP.
TCP/IP equivalent of OSI CLTP.
UFS: See ULTRIX File System.
UI frame: Unnumbered, HDLC, information frame, used to
carry data not subject to flow control or error recovery.
ULTRIX File System (UFS): Set of UFS file-management
procedures called by programs to process files.
unconfirmed event report: Event report for which the
event sink does not return a response to the request, and the agent
might discard the event after transmitting it.
unconfirmed service: Service with nonnegotiable
parameters whose functioning is fully controlled by the requesting
entity.
unique identifier (UID): Attribute of all DECdns
clearinghouses, directories, soft links, child pointers, and object
entries that contains a unique value reflecting the date and time that
an entity and a named entity with counters was created. The timestamp
consists of two parts --- a time portion and a portion with the system
identifier of the node on which the name was created. This guarantees
uniqueness among timestamps generated on different nodes.
universal time coordination: See
Coordinated Universal Time.
unreachable node: Node to which the Network layer has
determined that the path exceeds the maximum hops of the network, or
the intermediate system either cannot recognize the destination address
or access the destination node by a usable path.
unstructured file view: Access context for a file that
recognizes only the file-contents data units in a file-access data unit
(FADU).
update: Routing process that periodically updates
routing information to reflect topology changes, such as circuits going
on or off, and changes that network managers make to routing
attributes. Level 1 routers send information about adjacent nodes to
all other routers in an area in level 1 LSPs, and level 2 routers send
information about adjacent areas to all other level 2 routers in level
2 LSPs.
update propagation: Immediate attempt by DECdns
software to apply a change to all replicas of the directory in which
the change was just made. An update propagation delivers changes in a
more efficient and timely way than a skulk, which is the periodic
distribution of a whole collection of changes.
update timestamp (UTS): Attribute (named
DNS$UTS) that identifies the time when the most recent change
was made to any attribute of a particular name in the namespace; for
directories, reflects changes made only to attributes that apply to the
directory as a whole (not to one of its replicas).
upline dumping: Transferring a copy of a memory image
from a target node to a load host node. Some systems, such as DEC
WANrouter systems and DECserver terminal servers, automatically upline
dump their image upon failure.
user: Defined as:
user element: Part of an application entity that
invokes the service primitives provided by one or more of the protocols
in the Application layer and, optionally, some provided by the
Presentation layer.
user entity: Part of an application process that
communicates with the OSI protocols.
user interface layers: Device and style layers of the
director.
UTC: See Coordinated Universal
Time.
UTS: See update timestamp.
virtual circuit: Independent logical path between two
entities for the purpose of exchanging data. Association between two
DTEs connected to a PSDN that makes it seem as if a specific circuit
were dedicated to them throughout the transmission. In reality, only a
logical connection is established: actual, physical circuits are
allocated according to criteria such as route availability and network
traffic.
virtual file: Unambiguously named collection of
structural information. The information in a virtual file includes
values for the file attributes that describe a file's properties (such
as its file name, size, and file-access structure) and descriptions of
a file's file-access data units (FADUs). Used by FTAM software.
virtual filestore: Idealized filestore defined by the
FTAM virtual filestore model to serve as an intermediary between real
filestores.
virtual filestore model: Common model that describes
files (alone or in organized collections) and the possible actions that
FTAM software can perform on those files.
virtual terminal: Abstract representation of a real
terminal, complete with terminal operations such as reading text from
the keyboard, writing text to the screen, and moving the cursor. Using
this model, any terminal connected to a system can access any other
system regardless of the types of machines in use. See also
Virtual Terminal software.
virtual terminal association: Communication
established between two virtual terminal systems, one initiator and one
responder. The association allows the two systems to exchange request
for information and their corresponding responses. Performed by
DECnet-Plus Virtual Terminal software. See also
Virtual Terminal software.
Virtual Terminal software: DECnet-Plus software that allows users and applications of one host to log in to a remote host and then interact as normal terminal users of that host.
VisibleString: FTAM string composed of a definable
character set that includes alphanumeric characters, punctuation, and
graphics.
VMScluster alias: See cluster
alias.
VT: See Virtual Terminal
software.
WAN: See wide area network.
wide area network (WAN): Data communications network
that covers a wide geographical area, such as a country. Contrast
with local area network.
wide area network device driver (WANDD) software:
DECnet-Plus software that links a hardware device and layered software.
wildcard name: DECdns and network management: Name
that allows the looking up of groups of entries that have common name
characteristics.
window: Ordered set of consecutive data packets
authorized to cross the DTE/DCE interface of the logical channel used
for a switched virtual circuit (SVC) or permanent virtual circuit (PVC)
and for each direction of transmission.
window size: Maximum number of packets that are
allowed to be transmitted without an acknowledgment in a PSDN.
write access: Access right that grants users the
ability to change DECdns data.
X Recommendations: CCITT documents that describe data
communication network standards, for example, the X.25 packet switching
standard, X.400 message handling system, and X.500 directory services.
X.3: CCITT recommendation that describes the operation
of a packet assembler/disassembler (PAD) and PAD parameters.
X.21: CCITT recommendation that defines the physical
and electrical interface between data terminal equipment (DTE) and data
circuit-terminating equipment (DCE) of a PSDN; includes OSI layers 1--3
functions.
X.25: CCITT recommendation that defines the interface
between the data terminal equipment (DTE) and the data
circuit-terminating equipment (DCE) of a PSDN; provides an OSI Network
service for PSDNs. See also X.25 Protocol.
X25 Access module: Defined as:
X.25 address: Address of a specific DTE that allows
network access on X.25 networks.
X25 Client module: Defined as:
X.25 gateway access: Facility that allows a user of a
DECnet-Plus system not directly connected to an X.25 network to access
facilities of that network through an intermediary gateway node.
X.25 line: Line supplied by a PSDN; also called
DTE.
X.25 network: PSDN that can be accessed by using an
interface that complies with the X.25 recommendation.
X.25 Protocol: Connection-oriented network interface
protocol; negotiates services for a PSDN.
X25 Protocol module: Defined as:
X25 Relay module: Network management module that
manages the entities that constitute the X25 Relay module; interfaces
with the X25 Access module to receive an incoming switched virtual call
and then make an outgoing call back out through the X25 Access module;
resides in the DNA Application layer.
X.25 security: X.25 utility that allows control of use
of X.25 systems and protects X.25 systems from unauthorized use.
X25 Server module: Defined as:
X.28: CCITT recommendation that specifies how to
control the packet assembler/disassembler (PAD) facilities that a user
can select from a terminal; defines procedures for setting up and
clearing a link between the PAD and the terminal and for setting up and
clearing virtual circuits.
X.29: CCITT recommendation that specifies how to
control the PAD facilities that the user can select from the remote
packet-mode DTE; defines the procedures for exchanging PAD control
information and PAD messages.
X.29 terminal: Remote virtual terminal.
X.75: CCITT recommendation that specifies procedures
for communicating between PSDNs.
X.121: CCITT recommendation that defines the format of
a DTE address.
X.400: Series of OSI standards, defined by CCITT and
approved by it, that specify how networks exchange electronic mail
messages.
XID frame: Frame in HDLC used to exchange operational
parameters between participating stations.
X/Open Transport Interface (XTI): Transport service
interface, which is independent of the transport provider, that is
between the transport user (a networking application or Session layer
protocol) and the transport provider; IEEE 1003.8 project.
XTI: See X/Open Transport Interface.
G.2 Acronyms
Table 1 shows DECnet-Plus acronyms and other acronyms related to
open networking.
| Acronym | Meaning |
|---|---|
| ACE | access control entry |
| ACL | access control list |
| ACS | access control string |
| ACSE | Association Control Service Element |
| AD | ISO Addendum |
| ADMD | Administration Management Domain |
| AEP | Applications Environment Profile |
| AFI | authority and format identifier |
| AFNOR | French national standards body |
| AM | active monitor |
| ANSI | American National Standards Institute |
| AOW | Asian and Oceania Workshop |
| APIA | Application Program Interface Association (X.400) |
| API | application programming interface |
| ASE | application service element |
| ASN | Abstract Syntax Notation |
| ASN.1 | Abstract Syntax Notation One |
| AUI | attachment unit interface |
| BCUG | bilateral closed user group |
| BEA | broadcast end-node adjacency |
| BER | basic encoding rules |
| BRA | broadcast router adjacency |
| BRI | Basic Rate Interface (of ISDN) |
| BSI | British Standards Institute |
| CALS | Computer-aided Acquisition and Logistic Support |
| CCITT | International Telegraph and Telephone Consultative Committee |
| CCR | Commitment, Concurrency, and Recovery |
| CD | Committee draft (ISO) |
| CEC | Commission of European Communities |
| CEN | European Committee for Standardization |
| CENELEC | European Committee for Electrotechnical Standardization |
| CEN/CENELEC | Joint European Standards Institution |
| CBEMA | Computer Business Equipment Manufacturer's Association |
| CEPT | European Conference of PTTs |
| CL | connectionless mode |
| CLNP | Connectionless Network Protocol |
| CLNS | Connectionless-Mode Network Service |
| CLTP | Connectionless Transport Protocol |
| CMISE | Common Management Information Service Element |
| CMIP | Common Management Information Protocol |
| CONS | Connection-Oriented Network Service |
| COS | Corporation for Open Systems |
| COSINE | Cooperation for Open Systems Interconnection Networking in Europe |
| CSMA-CD | Carrier Sense, Multiple Access with Collision Detection |
| CT | conformance testing |
| CTS | creation timestamp |
| CTS-WAN | Conformance Testing Services --- Wide Area Networks (now OSTC) |
| CUG | closed user group |
| DA | dynamic assignment |
| DAD | ISO Draft Addendum |
| DAF | Distributed Applications Framework |
| DAM | ISO Draft Amendment |
| DAP | Data Access Protocol |
| DCB | data-chain buffer |
| DCE | data circuit-terminating equipment |
| DCM | dynamic connection management |
| DDCMP | Digital Data Communications Message Protocol |
| DED | dynamically established data link |
| DIS | ISO Draft International Standard (DP accepted, second technical ballot) |
| DISP | ISO Draft International Standardized Profile |
| DLM | data link mapping |
| DNA | Digital Network Architecture |
| DNIC | data network identification code |
| DP | ISO Draft Proposal (has started first technical ballot) |
| DPDU | data link protocol data unit |
| DSAP | destination service access point |
| DSP | domain-specific part |
| DTE | data terminal equipment |
| EC | European Commission |
| ECMA | European Computer Manufacturer's Association |
| EDI | electronic data interchange format (X.12) |
| EG | Expert Group |
| EMA | Enterprise Management Architecture |
| EN | European Norm (profiles from CEN/CENELEC) |
| ENV | Draft European Standard |
| ES | end system |
| ES-IS | end system to intermediate system protocol |
| ESPRIT | Series of European Cooperative technical development projects |
| ETCOM | European Testing and Certification for Office and Manufacturing Protocols |
| ETG | EWOS Technical Guide |
| ETSI | European Telecommunication Standards Institute |
| EVD | event dispatcher |
| EWOS | European Workshop for Open Systems |
| FADU | file-access data unit |
| FAL | file access listener |
| FCS | frame checking sequence |
| FDDI | Fiber Distributed Data Interface |
| FDT | function dispatch table |
| FIPS | Federal Information Processing Standard |
| FIMS | ISO Project for Forms Information Management System |
| FNC | Federal Networking Council |
| FOD | Office Document Format |
| FPM | FTAM protocol machine |
| FTAM | File Transfer, Access, and Management |
| GAP | Gateway Access Protocol |
| GDMO | Guidelines for the Development of Managed Objects |
| GOSIP | Government OSI Profile |
| IDI | initial domain identifier |
| IDP | initial domain part |
| IEC | International Electrotechnical Commission |
| IEEE | Institute of Electrical and Electronics Engineers |
| IEEE/CS | IEEE Computer Society |
| INTAP | Interoperability Technology Association for Information Processing, Japan |
| IONL | Internal Organization of the Network Layer |
| IPC | Interprocess Communications (function in IEEE 1003.4) |
| IPSIT | International Public Service Information Technology |
| IRDS | Information Resource Directory Service |
| IS | (1) ISO International Standard; (2) Intermediate system |
| ISDN | Integrated Services Digital Network |
| IS-IS | intermediate system to intermediate system protocol |
| ISO | International Organization for Standardization |
| ISODE | ISO Development Environment |
| ISP | International Standardized Profile |
| I.T. | Information Technology |
| ITTF | Information Technology Task Force (ISO/IEC) |
| ITU | International Telecommunications Union |
| LAN | local area network |
| LAP | Link Access Protocol |
| LAPB | Link Access Protocol Balanced |
| LCN | logical channel number |
| LES | Layered Environment Services |
| LFDP | long-format data packet |
| LIN | LAN interworking network |
| LLC | logical link control |
| LSAP | link service access point |
| LSP | link state packet |
| MAC | media access control |
| MAU | media attachment unit |
| MEN protocol | Management Event Notification Protocol |
| MHS | message-handling system |
| MICE protocol | Management Information Control and Exchange protocol |
| MMS | Manufacturing Message Systems |
| MIA/NTT | Multivendor Integration Architecture (Nippon Telephone and Telegraph) |
| MOM | Maintenance Operations Module |
| MOP | Maintenance Operations Protocol |
| MOTIS | Message Oriented Text Interchange System |
| MTA | message transfer agent (X.400) |
| MTU | maximum transmission unit |
| NAS | Network Applications Support |
| NBS | National Bureau of Standards (now NIST) |
| NCC | National Computing Centre, Inc. |
| NCF | Network Computing Forum |
| NCL | Network Control Language |
| NCP | Network Control Program |
| NET | network entity title |
| NICE Protocol | Network Information and Control Exchange Protocol |
| NIST | National Institute of Standards and Technology (formerly NBS) |
| NMF | Network Management Forum (OSI/NMF) |
| NM | network management |
| NNPC | Network New Products Committee |
| NP | new project |
| NPDU | network protocol data unit |
| NSAP | network service access point |
| NSCTS | namespace creation timestamp |
| NSP | Network Services Protocol |
| NWI | ISO New Work Item |
| ODA | Office Document Architecture (ISO Standard 8613) |
| ODIF | Office Document Interchange Format (part of ODA) |
| ODP | open distributed processing |
| OIW | OSI Implementors Workshop (NIST) |
| OMG | Object Management Group |
| OSAK | OSI Applications Kernel |
| OSF | Open Software Foundation |
| OSI | Open Systems Interconnection |
| OSTC | Open Systems Testing Consortium (formerly CTS-WAN) |
| OTF | Open Token Foundation |
| PAD | packet assembler/disassembler |
| PAGODA | Profile Alignment Group on ODA (consists of EWOS EG on ODA, NIST ODA/ODIF SIG, POSI) |
| PAR | Proposal and Request (IEEE) |
| PBX | Public Branch Exchange |
| PCI | protocol control information |
| PCTE | Portable Common Tool Environment (ECMA and ESPRIT projects) |
| PDAD | ISO Proposed Draft Addendum |
| PDISP | ISO Proposed Draft International Standardized Profile |
| PDES | Product Data Exchange Specification |
| PDU | protocol data unit |
| PICS | Protocol Implementation Conformance Statement |
| PODA | European Group on ODA |
| POSI | Promoting Conference for OSI (Japan) |
| PRMD | Private Management Domain |
| PSE | packet switching exchange |
| PSDN | packet switching data network |
| PSTN | public switched telephone network |
| PTT | Postal, Telephone and Telegraph Authority |
| PVC | permanent virtual circuit |
| RD | redirect packet |
| RDA | remote database access |
| RISC | Reduced Instruction Set Computer |
| ROSE | Remote Operations Service Element |
| RPC | remote procedure call |
| RPOA | Recognized Private Operating Agency |
| RTS | Reliable Transport Service |
| RTSE | Reliable Transfer Service Element |
| SAB | Standards Activities Board (IEEE/CS) |
| SAP | service access point |
| SASE | Specific Application Service Element |
| SC | subcommittee |
| SCC | Standards Coordinating Committee (IEEE/CS) |
| SDO | Standards Development Organization |
| SDU | service data unit |
| SFDP | short format data packet |
| SG | subgroup |
| SGFS | Special Group on Functional Standardization (part of JTC1) |
| SGML | Standard Generalized Mark-up Language (ISO 8879) |
| SIG | special interest group |
| SIGMA | Software Industrialized Generator and Maintenance Aids (Japan) |
| SILS | Standard for Interoperable LAN Security |
| SMDS | Switched Multi-Megabit Data Service |
| SNAP | Subnetwork Access Protocol |
| SNDCF | subnetwork dependent convergence function |
| SNP | sequence number packet |
| SONET | synchronous optical network |
| SPAG | Standards Promotion and Application Group |
| SSAP | session service access point |
| SVC | switched virtual circuit |
| SWG | Special Working Group |
| T1 | Standard for High Bandwidth WAN Connections |
| TC | Technical Committee |
| TCCC | Technical Committee on Computer Communications (IEEE) |
| TCOS | Technical Committee on Operating Systems (IEEE) |
| TDF | time differential factor |
| TFS | Transparent File Service (IEEE 1003.8 Project) |
| TG | Technical Group |
| TOP | Technical Office Protocols |
| TP | Transport Protocol |
| TPDU | transport protocol data unit |
| TR | Technical Report |
| TSAP | transport service access point |
| TSG | Technical Study Group |
| TS provider | Transport Service provider |
| TS user | Transport Service user |
| UDP | User Datagram Protocol |
| UID | unique identifier |
| ULA | upper layer architecture |
| ULCT | upper layer conformance testing |
| UTC | Coordinated Universal Time |
| UTP | unshielded twisted pair |
| UTS | update timestamp |
| VSAT | very small aperture terminal (satellite network) |
| VT | Virtual Terminal (OSI Protocol) |
| VTAM | Virtual Telecommunications Access Method |
| WAN | wide area network |
| WD | Working Draft |
| WG | Working Group |
| XTI | X/Open Transport Interface (network stack independent transport) |
INTRO_PROFILE_015.HTML OSSG Documentation 2-DEC-1996 12:54:41.58
Copyright © Digital Equipment Corporation 1996. All Rights Reserved.