proxy database: The database that provides OpenVMS
identities for remote NFS clients and UNIX-style identities for local
NFS client users; provides proxy accounts for remote processes.
pseudodevice: A software device used to implement
special-purpose transports and not directly associated with hardware.
public domain: Intellectual property available to
people without paying a fee.
RARP: See Reverse Address Resolution
Protocol.
RCD: See RMT/RCD.
RCP: See remote copy program.
reachable node: The node to which the local node has a
usable communications path.)
read access: The access right that grants the ability
to view data.
reassembly: The process of piecing together datagram
fragments to reproduce the original datagram based upon the
fragmentation data in the IP header of the datagram.
Record Management Services (RMS): The OpenVMS data
management subsystem that defines the rules that govern the internal
organization of and the methods of accessing file data, including how
files are named and cataloged in directories.
reliability: The ability of a protocol to recover data
that is damaged, lost, duplicated, or delivered out of order.
relative path name : A path name that does not start
at the root; default directory is merged with the relative path name to
form the absolute path name.
remote boot (BOOTP): The software that supports the
downloading of system images and other types of files to requesting
clients.
remote copy program (RCP): The program based on the
Berkeley UNIX (see BSD) rcmd protocol that permits files to be
copied from one computer to another by an extension to the syntax of
the UNIX cp (copy) command. (RCP) does not provide the
word-length adaptability and flexibility that the FTP protocol does.
remote line printing (LPR/LPD): The remote printing
services for UNIX and OpenVMS client hosts.
remote node: A node in the network other than the
local node.
remote procedure call (RPC): A programming interface
for implementing the client/server model of distributed computing. In
general, a request is sent to a remote system to execute a designated
procedure, using arguments supplied, and the result returned to the
caller. See also Sun RPC.
remote shell: A program that sends a command, shell,
script, or command procedure to a remote host for execution.
remote task: A task either executing at a remote host
or originating there.
repeater: A bidirectional device that amplifies or
resynchronizes signals into standard voltages, currents, and timing;
propagates electrical signals from one Ethernet to another without
making routing decisions or providing packet filtering; Physical layer
intermediate system. See also bridge and
router.
Request for Comments (RFC): A series of documents,
begun in 1969, that describes the Internet suite of protocols and
related experiments. Very few RFCs describe Internet standards, but all
Internet standards are written as RFCs.
resolver: A mechanism or process to correlate a
network host name into an appropriate network address in support of
network applications---a network name resolver. See
BIND resolver.
reserved port: An assigned port that provides services
to unknown callers by providing a service contact point; reserved port
numbers range from 1 to 255.
resynchronization: A process that enables the recovery
of user information lost or corrupted during transfer across an
association. Sets the association back to the state it was in at a
specified point in the transfer.
retransmission: A method of error recovery in which
stations receiving messages acknowledge the receipt of correct messages
and, on receipt of incorrect messages, either do not acknowledge or
acknowledge in the negative. The lack of acknowledgment or receipt of a
negative acknowledgment indicates to the sending station that it should
transmit the failed message again.
Reverse Address Resolution Protocol (RARP): The TCP/IP
protocol that provides the reverse function of ARP. This protocol maps
a physical (hardware) address to an IP address. Often used by diskless
nodes when they first initialize to find their Internet address.
reverse domain: An Internet domain that BIND servers
use to map IP addresses to domain names.
RFC: See Request for
Comments.
RFC 822: The TCP/IP standard format for electronic
mail message headers; often referred to as "822 messages". The name
comes from RFC 822 that contains the specification; previously known as
733 format.
RIP: See Routing Information
Protocol.
rlogin: Remote login: The Berkeley 4.3 BSD service
that allows users of one machine to connect to other systems across the
Internet and interact as if their terminals are connected the machines
directly.
RMS: See Record Management
Services.
RMT/RCD: Remote command that allows remote users to
access magnetic tapes and CD drives.
root: The top level directory in a UNIX-style file
system; also used to indicate a user (the superuser) who has special
privileges. See superuser.
root mode: The file protection placed on a container
file when it is created.
root name: The element of a path name that identifies
the target file system.
root server: An Internet name server that knows about
all of the top-level domains on the Internet network; the master
servers for the Internet root zone.
round-trip delay: The total time during communications
that implement a protocol with positive acknowledgments, for a message
to be transmitted, arrive at its destination, and its corresponding
acknowledgment to be sent and subsequently received by the sender of
the original message.
round-trip time (RTT): A variable computed during TCP
sessions that indicates the total time required to send a TCP segment
to a remote host and receive a reply.
route: The path over the network that information
takes to get from one source to its destination.
route through: Data packets not destined for the local
node.
routes database: The UCX database that specifies
Internet gateways.
routed: See Route
Daemon.
Route Daemon (routed): A program that runs
under 4.2BSD/4.3BSD UNIX systems (and derived operating systems) to
propagate routes among machines on a local area network using the
Routing Information Protocol; pronounced "route-d."
router: A node that can send and receive data and also
forward data to other nodes.
routing: A Network layer function, implemented in
intermediate systems, that determines the path along which data travels
to its destination and the movement of that data. See also
decision.
routing database: The database that contains routing
information, including destination host names, IP addresses for the
hosts, gateway host names, and IP addresses for the gateways. There are
two route databases: the static route database that is maintained on
disk and the volatile database in memory.
routing domain: A set of hosts and routers within a
single administrative domain that operates according to the same
routing procedures.
Routing Information Protocol (RIP): The protocol that
enables gateways to broadcast their current routing database to hosts
and networks that are connected directly to them. UCX
software implements the RIP through its dynamic routing server.
Routing Protocol: A protocol sent between routers by
which routers exchange information on how to route to various parts of
the network. The TCP/IP family of protocols has many of this type of
protocol, such as RIP, EGP, BGP, OSPF, and dual IS-IS.
RPC: See remote procedure
call and Sun RPC.
rshell: Remote shell; a remote utility that gives the
user with a shell session on a remote host.
RTL: See Run-Time Library.
RTT: See round-trip time.
Run-Time Library (RTL): A collection of OpenVMS
procedures available to native mode images at run time; provide support
routines for high-level language compilers.
SCALE: A TCP window scaling option; allows window
information to be interpreted as being scaled by 1 to 16 powers of 2,
thus increasing the size of the effective window.
secondary server: A master BIND server that receives
authoritative database information from a primary server. See
also BIND server, cache server,
forwarder server, and primary server.
segment: A unit of data exchanged by the TCP modules.
segment length: The amount of sequence number space
occupied by a segment, including controls that occupy sequence space.
sequence number: A 32-bit field in the TCP header that
contains the sequence number of a sequenced control flag, the first
byte of data, or empty segments (the sequence number of the next data
octet to be sent).
Serial Line Internet Protocol(SLIP): A protocol
designed to allow a host to connect to another host over serial lines,
such as telephone circuits or RS-232 cables.
server: A process that offers a service to another
process over the network and accepts requests from other processes,
known as clients.
service: (1) A task that an application can carry out.
(2) The interface provided by a service element or layer for accessing
one or more function.
service interface: The boundary at which a layer
provides a service to the adjacent higher layer in the network
architecture; may vary between implementations.
service parameter: The means by which a service user
and a service provider exchange information.
service provider: In network architecture, the service
element or layer that provides a set of services to the layer
immediately above.
service specification: An international standard that
describes the functions and service parameters of every service of a
service provider.
service user: An application program, service element,
or Network layer that uses the services of a service provider.
services database: The UCX database created by default
that contains one entry for each UCX service configured.
Simple Mail Transfer Protocol (SMTP): An Internet
standard protocol for transferring electronic mail messages from one
machine to another; specifies how two mail systems interact and the
format of control messages they exchange to transfer mail.
Simple Network Management Protocol (SNMP): The network
management protocol of choice for TCP/IP-based internets; allows remote
monitoring and management of network devices (particularly routers and
servers) from across an Internet.
slave server: A name server that has no access to the
Internet and relies on forwarder servers to resolve queries that it
cannot resolve locally. As slave servers receive information from
forwarder servers, they store that information in their cache. See
also cache server, forwarder
server, primary server, and secondary
server.
SLIP: Serial Line Internet Protocol---a protocol
designed to allow a host to connect to a TCP/IP internetwork over a
telephone connection.
SMI: See Structure of Management
Information.
SMTP: See Simple Mail Transfer
Protocol.
SNMP: See Simple Network Management
Protocol.
socket: The end point of communication to which an IP
address and port may be bound. When writing a UCX application, it is a
data structure that is part of the Internet pseudodevice created every
time an OpenVMS process assigns a communication channel. The other part
of the Internet pseudodevice is the device socket.
source: The IP header field that contains the IP
address of the datagram's point of origin.
source port: A 2-octet value in the TCP or UDP header
field that identifies the upper-level application or protocol
associated with the data in the segment.
spanning tree: A logical arrangement created by
bridges in an extended LAN in which all LANs are connected and there
are no loops.
split horizon: When a router (or group of routers work
together) accepts routing information from multiple external networks,
but does not pass on information learned from one external network to
others. This is an attempt to prevent false routes to a network from
being propagated because of gossip or counting to infinity.
splitting: The process of mapping one transport
connection to several network connections.
stream-oriented: The type of transport service that
allows its client to send data in a continuous stream; guarantees that
all data will be delivered to the other end in the same order as sent
and without duplicates. Also known as a reliable transport service.
Structure of Management Information (SMI): The rules
used to define the objects that can be accessed by means of a network
management protocol. See also Management Information
Base.
subnet: An organization of hosts within a network into
logical groups. A network can be comprised of several subnets. The
portion of a network, which might be a physically independent network,
that shares a network address with other portions of the network and is
distinguished by a subnet number. A subnet is to a network what a
network is to an internet.
subnet address: A part of the Internet addressing
scheme. If a site uses a single IP address for multiple physical
networks, there is one subnet address for each physical network. Each
such address is composed of the network part of the full address and
part of the local part (host).
subnet field: A bit field in an IP address that
denotes the subnet number. The bits making up this field are not
necessarily contiguous in the address.
subnet mask: A method of representing the portion of
the IP network address that is devoted to subnet address. Each bit that
is turned on (binary one) in the mask is interpreted as part of the
network and subnet address. Synonymous with network mask. See
address mask.
Sun RPC: An easy and popular paradigm for implementing
the client/server model of distributed computing. In general, a request
is sent to a remote system to execute a designated procedure, using
arguments supplied, and the result returned to the caller.
superuser: A UNIX user who has been granted special
privileges; has an effective UID of 0.
symbiont: (1) A process that transfers record-oriented
data to and from a mass storage device; for example, from disks to
printers. (2) Synonym for daemon.
symbolic link: A file that contains the name of the
file to which it is linked. The referenced file is used whenever the
symbolic link file is opened.
synchronous transmission: Data transmission in which
characters are transmitted at a fixed rate. The transmitter and
receiver are synchronized, gaining greater efficiency than in
asynchronous transmission. Synchronous transmissions send a
predetermined group of "sync" characters ahead of a long stream of
data. The sync characters enable the communicating devices to
synchronize with each other in accordance with a time clock at each
end. Contrast with asynchronous transmission.
syntax: The rules for formatting/interpreting data.
TAC: See terminal access
controller.
target system: The intended destination of messages.
TCP: See Transmission Control
Protocol.
TCP/IP: An Internet suite of protocols. See
also Transmission Control Protocol and
Internet Protocol.
TELNET: An Internet protocol for remote terminal
connection. TELNET allows a user at one site to interact with remote
timesharing systems at another site as if the user's terminal were
directly connected to the remote host.
terminal access controller (TAC): A program and
hardware that connects terminals to the Internet, usually using dialup
modem connections.
terminal emulator: A program that allows a computer to
emulate a terminal; a workstation thus appears as a terminal to the
host.
terminal server: A device that handles terminal
operations for host nodes on a LAN; can be used to connect terminal
users to nodes on the same LAN and to users on nodes located off the
LAN. Off-loads the terminal connection and I/O responsibilities from
host nodes, and reduces the number of direct terminal connections to
each host, thus saving substantial power, packaging, and cabling
expense.
terminating packet: A packet whose destination is the
local node.
TFTP: See Trivial File Transport
Protocol.
thread: (1) A request from an NFS client to the NFS
server. (2) A single unit of execution within a program.
throughput: A measure of how much data is sent, or can be sent, between two points in a specified unit of time; often used in either of two contexts:
time to live (TTL): A field in the IP header that
indicates how long this packet should be allowed to be forwarded to
other routers before being discarded.
timeo: A timeout option for the NFS mount
command.
TN3270: TELNET options that allows TELNET users to
connect to hosts that support 3270 model terminals.
token ring: A type of LAN that has stations wired in a
ring, where each station constantly passes a special message (a
"token") on to the next; technically referred to as IEEE 802.5.
topology: The architecture of a network. A network
topology shows the computers and the links between them within a
network.
traffic: The measurement of data flow, volume, and
velocity over a communications link.
transceiver: Transmitter-receiver; a physical device
required in baseband networks that takes the digital signal from a
computer or terminal and imposes it on the baseband medium; connects a
host interface to a LAN, such as Ethernet.
transient information: Network management information
carried in an operation; is meaningful only while the operation is
being performed.
transit network: A network that passes traffic between
networks in addition to carrying traffic for its own hosts; must have
multiple connections to the internet.
Transmission Control Protocol (TCP): A Transport layer
protocol that provides the reliable, full-duplex, stream service on
which many application protocols depend. TCP allows a process on one
host to send a stream of data to a process on another. It is
connection-oriented in the sense that before transmitting data,
participants must establish a connection.
Transmission Control Protocol/Internet Protocol
(TCP/IP): The acronym for the suite of application and
transport protocols that run over IP, for example, FTP, TELNET, and UCP
as well as TCP and IP themselves.
Transport layer: The layer in the TCP/IP architecture
model where network traffic is passed between an application on one
host and an application on another host.
Trivial File Transport Protocol (TFTP): The Internet
protocol for file transfer with minimal capability and minimal
overhead. The simple design of the facility is intended for use in
application environments that do not require complex interactions among
clients and servers. TFTP is a simple service running on top of UDP,
using timeout and retransmission to ensure that data arrives. The
sending side transmits a 512-byte, fixed-size file, and awaits an
acknowledgment for each block before sending the next. The receiver
acknowledges each block. See also File Transfer
Protocol.
TTL: See time to live.
tunneling: The encapsulation of protocol A within
protocol B such that A treats B as though it were a Network Interface
layer. Used to get data between administrative domains that use a
protocol not supported by the internet connecting those domains.
UAF: See user authorization
file.
UCP: See UCX Control Program.
UCX: The widely used name that refers to the DIGITAL
TCP/IP Services for OpenVMS product. Originally stood for "ULTRIX
Connection."
UCX Control Program (UCP): The UCX network management
control software; includes a command-line interface.
UDP: See User Datagram
Protocol.
UID: See user identification.
UNIX-style file system: An organization of files based
on the UNIX operating system.
UNIX-to-UNIX Copy Program (UUCP): A program that
allows one UNIX system to copy files to or from another UNIX system.
Universal Time Coordinated (UTC): Greenwich Mean Time
user authorization file (UAF): An OpenVMS file that
contains account names and their associated attributes.
User Datagram Protocol (UDP): An Internet transport
protocol. A connectionless, unreliable Transport layer protocol for the
exchange of requests and replies between networked hosts. UDP, like
TCP, uses IP for message delivery from one host to another; however,
unlike TCP, UDP provides for exchange of datagrams without
acknowledgments or guaranteed delivery of data. Each UDP message
contains the data sent by a user process, a destination port number,
and a source port number.
user identification (UID): The UNIX identification
code for a user.
UUCP: See UNIX-to-UNIX Copy
Program.
virtual circuit: The network service that allows two
processes to communicate as if they were directly connected, regardless
of the structure of the underlying subnet.
WAN: See wide area network.
well-known port: A port number assigned for use by a
specific network application for connections made with either UDP or
TCP.
wide area network (WAN): A network, usually
constructed with serial lines, which covers large geographic areas.
wildcarding: A method for generalizing parts of a
OpenVMS file designation to encompass a set of files by substituting a
symbol to represent one or more characters. OpenVMS wildcarding symbols
are % (for one character) and * (for a character string of any length,
including zero).
window: A 2-octet field in a TCP header indicating the
number of data octets (relative to the acknowledgment number in the
header) that the sender is currently willing to accept.
write access: An Access right that grants users the
ability to change data.
zone: A subdivision of the Internet hierarchy that
starts at a domain and extends down to leaf domains (individual host
names) or to domains where other zones begin; usually represents an
administrative boundary. Contrast with domain.
zone file: A master name server file that describes the domain names for which the server has authority.
G.2 Acronyms
Table 1 shows DIGITAL TCP/IP Services for OpenVMS acronyms and
other acronyms related to open networking.
| Acronym | Meaning |
|---|---|
| ACK | acknowledgment |
| ACL | access control list |
| ACP | ancillary control process |
| ANSI | American National Standards Institute |
| API | application programming interface |
| ARP | Address Resolution Protocol |
| ASCII | American Standard Code for Information Interchange |
| ATM | asynchronous transfer mode |
| BBS | Bulletin Board System |
| BGP | Border Gateway Protocol |
| BIND | Berkeley Internet Name Domain |
| BOOTP | Bootstrap Protocol |
| bps | bits per second |
| BSD | Berkeley Software Distribution |
| CFS | container file system |
| CFSRTL | container file system run-time library |
| CSLIP | Compressed Serial Line Internet Protocol |
| DCE | Distributed Computing Environment |
| DCL | Digital Command Language |
| DEK | data encryption key |
| DES | data encryption standard |
| DNS | Domain Name Service |
| eSNMP | extensible Simple Network Management Protocol |
| EGP | External Gateway Protocol |
| FDDI | Fiber Distributed Data Interface |
| EOF | end of file |
| EOL | end of line |
| FQDN | fully qualified domain name |
| FTP | File Transfer Protocol |
| GID | group identification (UNIX) |
| IAB | Internet Architecture Board |
| ICMP | Internet Control Message Protocol |
| IGP | Internal Gateway Protocol |
| InterNIC | Internet Network Information Center |
| IP | Internet Protocol |
| ISDN | Integrated Services Digital Networks |
| IVP | installation verification procedure |
| Kbps | kilobits per second |
| LAN | local area network |
| LPD | line printer daemon |
| LPR | remote line printing |
| MBUF | memory buffer |
| MFD | master file directory |
| MIB | Management Information Base |
| MIBII | Management Information Base II |
| MTU | maximum transmission unit |
| MX | mail exchanger |
| NAK | negative acknowledgment |
| NFS | Network File System |
| NIS | Network Information Service |
| NOC | Network Operations Center |
| NTP | Network Time Protocol |
| PDU | protocol data unit |
| PING | packet internet groper |
| POP | Post Office Protocol |
| PPP | Point-to-Point Protocol |
| PSDN | Packet Switching Data Network |
| PWIP | PATHWORKS Internet Protocol |
| RARP | Reverse Address Resolution Protocol |
| RCP | remote copy |
| REXEC | remote execute |
| RFC | Request for Comments |
| RLOGIN | remote login |
| RIP | Routing Information Protocol |
| RMS | Record Management Services |
| RPC | remote procedure call |
| RSH | remote shell |
| RTL | run-time library |
| RTT | round-trip time |
| SLIP | Serial Line Internet Protocol |
| SMI | structure of management information |
| SMTP | Simple Mail Transfer Protocol |
| SNMP | Simple Network Management Protocol |
| TAC | terminal access controller |
| TCP | Transmission Control Protocol |
| TCP/IP | Transmission Control Protocol/Internet Protocol |
| TFTP | Trivial File Transport Protocol |
| TP | Time Protocol |
| TTL | time to live |
| UAF | user authorization file |
| UCP | UCX Management Control Program |
| UCX | DIGITAL TCP/IP Services for OpenVMS |
| UDP | User Datagram Protocol |
| UID | user identification (UNIX) |
| UTC | Universal Coordinated Time |
| UUCP | UNIX-to-UNIX Copy Program |
| WAN | wide area network |
| WKS | Well Known Server |
| XDR | external data representation |