HP 3000 Manuals HP 3000 Manuals
GLOSSARY access port. A special interface card in the system cabinet through which the MPE XL system console is connected. address. A numerical identifier defined and used by a particular protocol and associated software to distinguish one node from another. address key. See X.25 address key. address resolution. In NS networks, the mapping of node names to IP addresses and the mapping of IP addresses to subnet addresses. address resolution protocol. ARP. A protocol used by LAN links with Ethernet enabled that provides a means of exchanging addressing information between Ethernet nodes. adjacent. A node on a point-to-point network that is connected to another node by a single link with no intervening nodes. ASCII. American National Standard Code for Information Interchange. A character set using 7-bit code used for information interchange among data processing and data communications systems. The American implementation of International Alphabet No. 5. asynchronous. Term used to describe a device's mode of operation whereby a sequence of operations are executed irrespective of time coincidence with any event. Devices that are directly accessible by people (for example, terminal keyboards) operate in this manner. Attachment Unit Interface. AUI. The cable that runs between each node (host, DTC, or other device) and the Medium Attachment Unit (MAU) that connects it to the LAN in a ThickLAN configuration. autodial. A dial link in which the remote node's telephone number is automatically dialed by a modem or other device with this capability. backbone LAN. A thick LAN cable conforming to the IEEE 802.3 Type 10 BASE 5 Standard. back-to-back configuration. A DTC configuration whereby MPE users connected to one DTC can communicate with a non-MPE XL system connected to another DTC via the LAN.( See also Local Switching) backup configuration file. A file that contains a copy of the information contained in the configuration file. The backup file, called NMCBACK.group. account by default, is updated with the configuration for a subsystem each time that subsystem is validated. banner. A welcome message displayed on your screen. On the local OpenView workstation a banner appears when a remote connection is established with the OpenView DTC Manager. A banner also can appear when you log on to MPE. baud. Measure of the speed at which information travels between devices, most commonly used in reference to terminal speed settings. Baud represents signal events per second. When one bit represents each signal change, baud is the same as "bits per second". binary mode. Data transfer scheme in which no special character processing is performed. All characters are considered to be data and are passed through with no control actions being taken. bit. Binary digit. A unit of information that designates one of two possible states, which are represented by either 1 or 0. block mode. Terminal processing mode in which groups, or "blocks", of data are transmitted all at once. BNC T-Connector. Connector used to connect a computer or a component such as a DTC to the LAN in a ThinLAN configuration. boundary. See network boundary. bps. Bits per second. The number of bits passing a point per second. broadcast. Communication method of sending a message to all devices on a link simultaneously. buffer. A logical grouping of a system's memory resources used by NS3000/XL. byte. A sequence of eight consecutive bits operated on as a unit. call. In X.25, a call is an attempt to set up communication between two DTEs using a virtual circuit. Also known as a virtual call. call collision. A conflict that occurs at a DTE/DCE interface when there is a simultaneous attempt by the DTE and DCE to set up a call using the same logical channel identifier. called address. When a node sends out a call request packet, the packet contains the address of the destination node. The address of the destination node is the called address. calling address. When a node receives an incoming call packet, the packet contains the address of the sending node. The address of the sending node is the calling address. carrier. A continuous wave that is modulated by an information bearing signal. catenet. See internetwork. CCITT. Consultative Committee for International Telephony and Telegraphy. An international organization of communication carriers, especially government telephone monopolies, responsible for developing telecommunication standards by making recommendations. The emphasis is on "recommendations"; no carrier is required to adhere to a CCITT recommendation, although most do so in their own interests. CIB. The channel input/output bus in the backplane of an HP 3000. circuit-switching network. A type of data communications network wherein a physical and exclusive link is maintained between two communicating devices for the call duration. An all-digital, circuit-switching network is often referred to as an X.21 network. closed user group. An X.25 user facility that allows communication to and from a pre-specified group of users and no one else. compatibility mode. Processing mode on 900 Series HP 3000 computers that allows applications written for MPE V/E-based systems to be ported and run without changes or recompilation. computer network. A group of computer systems connected in such a way that they can exchange information and share resources. configuration. 1) The way in which computer equipment is physically interconnected and set up to operate as a system. 2) The layout of the computer system, including the MPE table, memory, and buffer sizes, that tells which peripheral devices are (or can be) connected to the computer and how they can be accessed. 3) The process of defining the characteristics of a network in software. For MPE XL-based computers, the operating systems are configured through use of the SYSGEN utility. Next, the Distributed Terminal Subsystem (DTS) link is configured by using NMMGR (running on the host) and may, in addition, be configured using the OpenView DTC Manager software (running on the OpenView Windows Workstation) depending on the type of network management you use. If a system is to run network services (NS3000/XL), network configuration is accomplished through use of NMMGR. Access to X.25 is configured in two parts. The X.25 XL System Access software is configured on the host through use of NMMGR. The DTC/X.25 Network Access software residing on the DTC is configured at the OpenView Windows Workstation through use of the OpenView DTC Manager. configuration file. The configuration file contains the information that the network needs in order to operate. This file also contains information necessary for link-level and NetIPC logging. The only file name that the system recognizes is NMCONFIG.PUB.SYS. control-X echo. Three exclamation marks ( !!!) output to the terminal screen when the cancel character (normally CTRL-X) is entered. control-Y trap. User-written procedure to which control is passed when the subsystem break character (normally CTRL-Y) is entered during execution of a program with subsystem break enabled. cross-validate. The process of assuring that information contained in two locations is consistent where it is imperative that it be consistent. For example, an automatic cross-validation occurs when you enter SYSGEN to assure that information contained in NMCONFIG.PUB.SYS agrees with system configuration data. CSMA/CD. Carrier Sense Multiple Access with Collision Detect, transmission access method used by the IEEE 802.3 LAN standard. CSN. See circuit-switching network. CTB. The cache transfer bus in the backplane of an HP 3000. CUG. See closed user group. data. Basic elements of information that can be processed or produced by a computer. Datacommunications and Terminal Controller. See DTC. data overrun. Transmitted data that is sent faster than the equipment on the receiving end is capable of receiving it. The resulting overflow data is lost. See also flow control. Datapac. The national public PSN of Canada. Datex-P. The national public PSN of West Germany. D bit. Delivery confirmation bit. Used in the X.25 protocol, the setting of the D bit in DATA packets indicates whether delivery acknowledgement of the packet is required from the local DCE or from the remote DTE. It therefore allows the choice between local and end-to-end acknowledgement. DCE. Data circuit-terminating equipment. The interfacing equipment required in order to interface to data terminal equipment (DTE) and its transmission circuit. Synonyms: data communications equipment, dataset. DDX. The national public PSN of Japan. dedicated printer. A printer that can be used by only one host on the LAN; the one specified in the Destination Node Name in that printer's configuration screen. demodulation. The process by which the information-bearing signal is retrieved from a modulated carrier wave. The inverse of modulation. destination node name. In DTS configuration, it is either 1) the name of a host that a user can be connected to by default (if switching is not enabled for that user, or if automatic modem connection is enabled), or 2) the name of the only host that can access a dedicated printer. device class. A collection of devices that have some user-defined relation. Device classes are assigned through use of the NMMGR configuration program. device-dependent characteristic. A file specification for which modifications are restricted because of the type of device on which the file is opened. For example, data directed to terminals must have a blocking factor of one. device driver. Software module that controls a specific type of input/output device. devicefile. A file being input to or output from any peripheral device except a disc. MPE XL allows operations to be performed on the device itself as if it were a file. device independence. A characteristic of the operating system that allows users to selectively redirect input/output from a program, session, or job without regard to the nature of the device. device name. See PAD name. Dial ID protocol. A proprietary Hewlett-Packard protocol that provides security checking and address exchange for dial links. dial link. A connection made through public telephone lines. direct-connect device. Asynchronous device that is connected directly to a DTC through an RS-232-C or RS-422 cable, with no intervening communications equipment. Also referred to as a "local connection." direct connection. A leased line, private line, or other non-switched link in a network. direct dial. A dial link through which only one remote node can be reached. direct-path branching. The process of directly accessing any screen in NMMGR by entering path names in the Command: field. The path name must be preceded by an at sign (@). download. The process of loading operating code and configuration files into the DTC's memory. The DTC is downloaded by the MPE XL host for LANs using host-based network management, and by the PC for DTCs managed by the OpenView DTC Manager. driver. Software that controls input/output devices including NS3000/XL links. DTC. Datacommunications and Terminal Controller. The DTC is a hardware device, configured as a node on a LAN, that enables asynchronous devices to access 900 Series HP 3000 computers. Terminals can either be directly connected to the DTC, or they can be remotely connected through a Packet Assembler Disassembler (PAD). The DTC can be configured with DTC/X.25 Network Access cards and DTC/X.25 Network Access software. A DTC/X.25 XL Network Link consists of two software modules: the X.25 XL System Access software (running on the host) and the DTC/X.25 Network Access software (running on the DTC). DTC identifier. An identifier used only within NMMGR to define the branch of the configuration file containing information about a particular DTC. The identifier must begin with a letter and can be up to eight characters long. DTC Manager. See OpenView DTC Manager. DTC node name. Unique name used to identify a DTC on the LAN. Node name format is nodename.domain.organization, with each of the three parts having up to 16 characters and beginning with either a letter or a digit. DTC station address (802.3 address). 12-digit hexadecimal number used to identify the DTC as a node belonging to the network configuration. Also called the LAN address or node address. DTC switching. A facility enabling terminal users to select any host system that they want to connect to. DTC switching is available only when the OpenView DTC Manager is used for network management. DTC/X.25 Network Access. The software that resides on the Datacommunications and Terminal Controller (DTC). To configure access to an X.25 network, you must configure two software components: the X.25 XL System Access (residing on the HP 3000 host and configured through use of NMMGR software), and the DTC/X.25 Network Access (configured on the OpenView Windows Workstation through use of the OpenView DTC Manager software). DTC/X25 Network Access card. This is the hardware card and channel adapter that provides X.25 Network Access. It resides in the Datacommunications and Terminal Controller (DTC). DTC/X.25 XL Network Link. Software and hardware that provides MPE XL access to private and public X.25 networks. The X.25 XL System Access software resides on an HP 3000 host and is configured through use of NMMGR. The DTC/X.25 Network Access software resides on the Datacommunications and Terminal Controller and is configured at the OpenView Windows Workstation. DTE. Data Terminal Equipment. Equipment that converts user information into data-transmission signals or reconverts received data signals into user information. Data terminal equipment operates in conjunction with data circuit-terminating equipment. DTS. Distributed Terminal Subsystem. This consists of all the Datacommunications and Terminal Controllers (DTCs) on a LAN, their LANIC cards (attached to the host), the LAN cable, and the host and DTC software that controls all related DTS hardware. duplex. Transmission method that allows two-way communication. If both ends of the transmission link can transmit simultaneously, it is called full duplex. If only one end can transmit at a time, it is half-duplex transmission. entry priority. The ranking that identifies the most desirable route used to reach a given remote node from a given local node in a point-to-point network. environment. A session that is established on a remote node. escape from data transfer character. A character that allows a user who is connected to a host system through the DTC to break that connection and return to the DTC switching user interface. The default is CTRL-K. This character is used only on networks managed by the OpenView Windows Workstation. escape sequence. A sequence of characters beginning with the escape character and followed by one or more other characters, used to convey control directives to printers, plotters, or terminals. Ethernet. A Local Area Network system that uses baseband transmission at 10 Mbps over coaxial cable. Ethernet is a trademark of Xerox Corporation. event log. One of three circular files stored on the OpenView windows workstation containing lists of all significant events reported by the DTCs for which it is the owner; that is, whose operating software/configuration it has downloaded. extended packet sequence numbering. One of the optional Network Subscribed Facilities that provides packet sequence numbering using modulo 128. If not subscribed, modulo 8 is used. facility. An optional service offered by a packet switching network's administration and requested by the user either at the time of subscription for network access or at the time a call is made. Also known as user facility. facility set. A facility set defines the various X.25 connection parameters and X.25 facilities that can be negotiated for each virtual circuit on a per-call basis. fast select. An optional packet-switching network facility by which user data may be transmitted as part of the control packets that establish and clear a virtual connection. FCS. Frame Check Sequence. A sequence of bits generated by X.25 at Level 2 that forms part of the frame and guarantees the integrity of its frame's content. The FCS is also used by the IEEE802.3 protocol to check the validity of frames. file equation. Assignment statement used to associate a file with a specific device or type of device during execution of a program. file number. Unique number associated with a file when the file is opened. The file number is returned in the FOPEN or HPFOPEN call used to open the file. It can be used to access that file until the file is closed. file specification. The name and location of a file. The full specification for a file includes the file name, group, and account. file system. The part of the operating system that handles access to input/output devices (including those connected through the DTC), data blocking, buffering, data transfers, and deblocking. flow control. A means of regulating the rate at which data transfer takes place between devices to protect against data overruns. flow control negotiation. One of the network subscribed facilities, selected at subscription time. This facility allows the Flow Control parameter to be negotiated at call set-up time, as opposed to having a predefined value. formal file designator. Name that can be used programmatically or in a file equation to refer to a file. FOS. Fundamental Operating System. The programs, utilities, and subsystems supplied on the Master Installation Tape that form the basic core of the MPE XL operating system. full gateway. A full gateway is a node that belongs to more than one network and has one IP address for each network. It uses store and forward to transfer packets between each network that it belongs to. gateway. A node that connects two dissimilar network architectures. A gateway can be either a single node (full gateway) or two gateway halves. gateway half. A node that works in conjunction with another node on another network to form an internetwork. The only protocol used by gateway halves is the NS Point-to-Point 3000/XL Link. See also full gateway. gateway-half link. A link between the two nodes of a gateway-half pair. Each of the two nodes of a gateway-half pair has a configured link (hardware interface card) that is used for the gateway half network interface. The NS Point-to-Point 3000/XL Link is the only link that can be used as a gateway-half link. gateway-half pair. A set of two nodes that are joined by a gateway-half link. Each node in the pair must have a gateway-half network interface configured, using the link. Guided Configuration. A method of configuring a node in which a subset of the complete NMMGR interface is presented and defaults of configurable values are used automatically. handshaking. A communications protocol between devices or between a device and the CPU. Provides a method of determining that each end of a communications link is ready to transmit or receive data, and that transmission has occurred without error. hop count. See internet hop count and intranet hop count host-based network management. Method of managing asynchronous communications for 900 Series HP 3000 computers. All of the control software is configured on a single MPE XL host and is downloaded to the DTCs that are managed by that host. With host-based management, there is a permanent relationship between each DTC and the host, and terminal users can access only the single MPE XL system that owns the DTC their terminal is connected to. host computer. The primary or controlling computer on a network. The computer on which the network control software resides. For HP purposes, it may also be used to distinguish the MPE XL system (host) from the DTC. HP block mode. Block mode transmission method employed by HP computers where the system controls the block mode handshake. When HP block mode is used, the user program need not concern itself with data transfer protocol. HP PPN. Hewlett-Packard Private Packet Network. Hewlett-Packard's own packet-switching X.25 network, which gives users full control over the administration and security of their data communication. HP TS8. A terminal server that can support up to eight asynchronous serial connections. When used in back-to-back configuration, users can access HP 3000 MPE/V systems on it via a DTC. idle device timeout. Timeout defined by the Configure:CPU command. When the timer lapses, a device connected to the DTC user interface that is still inactive will be disconnected. IEEE 802.3. A standard for a broadcast local area network published by the Institute for Electrical and Electronics Engineers (IEEE). This standard is used for both the ThinLAN and ThickLAN implementations of the LAN. IEEE 802.3 multicast address. A hexadecimal number that identifies a set of nodes. This address is used for multicast delivery. IEEE 802.3 nodal address. A unique hexadecimal number that identifies a node on an IEEE 802.3 LAN. initialization string. A sequence of control characters used to initialize a terminal, printer, or plotter when a connection is established from a host on the network. INP. Intelligent Network Processor. The card residing in the back of an MPE V-based node that provides a point-to-point or X.25 interface. interactive communications. Processing that allows users to enter commands and data at the terminal and receive an immediate response. Interactive processing occurs in session mode on MPE XL systems. internet communication. Communication that occurs between networks. internet hop count. The number of full gateways plus the number of gateway-half links that a packet must pass through in moving from source node to destination. Internet Protocol. A protocol used to provide routing between different local networks in an internetwork, as well as among nodes in the same local network. The Internet Protocol corresponds to Layer 3, the Network Layer, of the OSI model. See also IP address. internet routing. Internet routing involves all the processes required to route a packet from a node on one network to a destination node on another network. internetwork. Two or more networks joined by gateways. intranet communication. Communication that occurs between nodes in a single network. intranet hop count. The number of intermediate nodes that lie between a source and destination node on the same point-to-point network. intranet routing. Intranet routing involves all the processes required to route a packet from one node in a network to another node in the same network. intrinsic. System routine accessible by user programs which provides an interface to operating system resources and functions. Intrinsics perform common tasks such as file access and device control. IP. See Internet Protocol. IP address. Internet Protocol address. An address used by the Internet Protocol to perform internet routing. A complete IP address comprises a network portion and a node portion. The network portion of the IP address identifies a network, and the node portion identifies a node within the network. ISO. International Organization of Standards. An international federation of national standards organizations involved in developing international standards, including communication standards. LAN. Local Area Network. A collection of data communication systems sharing a common cable whereby each system can communicate directly with another. LAN address. See DTC station address. LANIC. See Local Area Network Interface Controller. LANIC physical path. The physical location (slot number) of the LANIC within the SPU. LANIC Self-Test. A ROM-based program on a LANIC card that tests and reports the status of the LANIC hardware. LAP. Link Access Protocol. The data link protocol specified by older versions (prior to 1980) of X.25 at Level 2 but still permitted and therefore usable. All new implementations of X.25 must use LAP-B, and all old implementations must migrate to LAP-B at a future date. LAP-B. Link Access Protocol - Balanced. The data link protocol specified by the 1980 version of X.25 at Level 2 that determines the frame exchange procedures. LAP-B must also be used over direct-connect NS Point-to-Point 3000/XL Links. LCI. Logical Channel Identifier. Local value on a network node which identifies the channel used to establish a virtual circuit (SVC or PVC) through an X.25 network. ldev. See logical device number. leased line. Data-grade telephone line leased directly to a subscriber and allocated specifically for the subscriber's needs. line speed. Speed at which data is transferred over a specific physical link (usually measured in bits or kilobits per second). link name. The name that represents a hardware interface card. The link name can contain as many as eight characters. All characters except the first can be alphanumeric; the first character must be alphabetic. Local Area Network Interface Controller (LANIC). A hardware card that fits into the backplane of the 900 Series HP 3000 computer and provides a physical layer interface for local area networks. local connection. See direct connection. local node. The computer that you are configuring or that you are logged on to. local switching. Feature of the DTC which permits back-to-back configuration (for connections to an HP 3000 MPE/V host), using two ports of the same DTC. logging. The process of recording the usage of network resources. Events can be logged to both the OpenView workstation and to the MPE XL host. logging class. A number defining the severity of any given event logged. An operator uses the logging classes to specify which events are to be logged. Class 1 (catastrophic event) is always logged. logical device number (ldev). A value by which MPE XL recognizes a specific device. All DTC devices that are configured as nailed devices through the NMMGR configuration have ldev numbers permanently assigned. The DTC devices can then be accessed programmatically through use of their ldev number. Non-nailed devices have ldev numbers that are assigned from a pool of available ldev numbers for the life of their connection to a system. log off. The termination of a job or session. log on. The process of initiating a job or session. logon device. See session-accepting device. loopback. The routing of messages from a node back to itself. LUG. Local User Group. A list defined for a particular DTC and card that specifies which remote nodes this DTC can send data to and also which remote nodes this DTC can receive data from. (See also Closed User Group). map, network. A drawing that shows the topology of the network. For networks managed by the OpenView DTC Manager a network map must be created through use of the OVDraw capability provided with the management software. A network map is also a hardcopy drawing used when planning a network. It shows network topology, node and network names, addresses, network boundaries (for an internetwork map), and link types. mapping. A set of characteristics that describe a route taken by messages to reach a destination node. This set of characteristics is configured with NMMGR at every node on a point-to-point network. One mapping is configured at each node for every other node on the network to which messages will be sent. MAU. Medium Attachment Unit. A device attached to a ThickLAN coaxial cable that provides the physical and electrical connection from the AUI cable to the coaxial cable. M bit. More data bit. Setting this bit in a DATA packet indicates that at least one more DATA packet is required to complete a message of contiguous data. MIT. Master Installation Tape. Magnetic tape containing the Fundamental Operating System for a 900 Series HP 3000 computer. modem. modulator/demodulator. A device that modulates and demodulates signals. Primarily used for modulating digital signals onto carriers for transmission and for performing the inverse function at the receiving end. Modems are essential for transmitting and receiving digital signals over telephone lines. modulo. Value used as the counting cycle for determining the send sequence number (N(S)) of frames sent across an X.25 network. modulation. Process in which certain characteristics of a carrier signal are altered in accordance with the changes of an information-bearing signal. MPE XL. MultiProgramming Executive XL. The operating system of the 900 Series HP 3000 computers. The NS3000/XL network services operate in conjunction with the MPE XL operating system. multiplexer. MUX. A device that allows multiple communication links to use a single channel. nailed device. A device with a permanently associated ldev that was assigned through the NMMGR configuration of the MPE XL host system on which the association is established. Nailed devices can be accessed programmatically through their ldev number. In contrast, non-nailed devices have ldev numbers that are assigned from a pool of available ldev numbers for the life of their connection to a system. native mode. The run-time environment of MPE XL. In Native Mode, source code has been compiled into the native instruction set of the 900 Series HP 3000 computer. neighbor gateway. A gateway that is in the same network as a given node. NetIPC. Network Interprocess Communication. Software that enables programs to access network transport protocols. network. A group of computers connected so that they can exchange information and share resources. network address. This can be either 1) the network portion of an IP address as opposed to the node portion, or 2) when referring to X.25 networks, it is a node's X.25 address. network boundary. The logical division between networks in an internetwork. network directory. A file containing information required for one node to communicate with other nodes in 1) an internetwork, 2) an X.25 network, or 3) a network that contains non-HP nodes. The active network directory on a node must be named NSDIR.NET.SYS. network interface. (NI). The collective software that enables data communication between a system and a network. A node possesses one or more network interfaces for each of the networks to which it belongs. Network interface types are LAN, point-to-point (router), X.25, loopback, and gateway half. The maximum number of supported NIs is 12, one of which is reserved for loopback. network management. The collective tasks required to design, install, configure, maintain, and if necessary, change a network. network map. A drawing that shows the topology of the network. For networks managed by the OpenView DTC Manager, a network map must be created using the OVDraw capability provided with the management software. Network Services. NS. Software application products that can be used to access data, initiate processes, and exchange information among nodes in the network. The HP 3000/XL Network Services include RPM, VT, RFA, RDBA, and NFT. network subscribed facilities. A set of parameters that the user chooses when he subscribes to the X.25 network; they include Flow Control Negotiation, Use of D-bit, Throughput Class Negotiation and Extended Packet Sequence Numbering. network transport. Software that corresponds to layers 4 and 3 of the OSI network architecture model. The function of this software is to send data out over the appropriate communications link, to receive incoming data, and to route incoming or outgoing data to the appropriate destination node. NFT. Network File Transfer. The network service that transfers disc files between nodes on a network. NI. See network interface. NMCBACK.PUB.SYS. The default file name for the file that contains a copy of the information contained in the configuration file (NMCONFIG.PUB.SYS). The backup file is updated with the configuration for a subsystem each time that subsystem is validated. NMCONFIG.PUB.SYS. A file that contains all the network configuration data for the 900 Series HP 3000 computer on which it resides. It includes information about the DTCs that can access the system as well as information about any Network Services (NS) products running on the system. This is the only file name allowed. NMDUMP. Node Management Services Trace/Log File Analyzer. A utility used to format log and trace files. NMMAINT. Node Management Services Maintenance Utility. A utility that lists the software module version numbers for all HP AdvanceNet products, including NS3000/XL. It detects missing or invalid software modules. NMMGR. Node Management Services Configuration Manager. A software subsystem that enables you to configure DTC connectivity and network access parameters for a 900 Series HP 3000 computer. NMMGRVER. Node Management Services Conversion Utility. A conversion program called NMMGRVER.PUB.SYS. It converts configuration files created with NMMGR from an earlier version to the latest format. NMSAMP1.PUB.SYS. Sample configuration file supplied with FOS that can be used as a template for DTS configuration. node. A computer that is part of a network. The DTC is also considered to be a node and has its own address. node address. The node portion of an IP address, which consists of a node portion and a network portion. Node Management Services Configuration Manager. See NMMGR. node name. A character string that uniquely identifies each system in a network or internetwork. Each node name in a network or internetwork must be unique; however, a single node can be identified by more than one node name. node names list. List defined on the OpenView workstation and subsequently downloaded to all DTCs for which it is the "owner"; the list specifies all the 900 Series HP 3000 hosts on the LAN that are accessible from the DTCs. non-adjacent. Describes a node on an NS Point-to-Point 3000/XL network that is separated from a given node by intervening or intermediate node. non-nailed device. A session accepting device that is not permanently associated with an ldev number at configuration time. When the user at such a device logs on to an MPE XL system,an ldev is assigned from a pool of ldevs set aside for this purpose at configuration time. The association between a non-nailed device and this temporarily assigned ldev exists only for the duration of the session. One advantage of the use of non-nailed device connections is that configuration is simplified, since it is not required that each non-nailed device be individually configured. NS3000/XL. A Hewlett-Packard data communication product that provides networking capabilities for MPE XL based HP 3000 minicomputers. NS3000/XL consists of a link and network services. NS3000/XL Link. Software and hardware that provides the connection between nodes on a network. Some of the NS3000/XL links available are the ThinLAN 3000/XL Link and its ThickLAN option, the DTC/X.25 XL Network Link, the NS Point-to-Point 3000/XL Link, and the EtherTwist/3000 link. NS3000/XL Network Services. Software applications that can be used to access data, initiate processes, and exchange information among nodes in a network. The services are RPM, VT, RFA, RDBA, and NFT. NSDIR.NET.SYS. Name of the active network directory file. See also network directory. octet. An eight-bit byte operated upon as an entity. OpenView DTC Manager. OpenView Windows application that enables you to configure, control, monitor, and troubleshoot the operation of the Distributed Terminal Subsystems on the LAN. OpenView Admin. An OpenView windows program that enables you to configure how your OpenView Windows applications will function. For example, it enables you to set a default map for the OpenView DTC Manager. OpenView Draw. One of the OpenView windows programs; used to draw the network map, and to label the components on it. OpenView Run. One of the OpenView windows programs; covers most of the control features used by the DTC Manager, including monitoring and diagnostic functions. OpenView Windows. The set of three programs: OV Admin, OV Draw and OV Run, running on the OpenView workstation under MS Windows, that acts as the platform for all OpenView applications, such as DTC Manager. OpenView Windows Workstation. This is the personal computer that provides software downloads to enable operation of the Datacommunications and Terminal Controller (DTC). The configuration software that runs on this workstation is called the OpenView DTC Manager software. OSI model. Open Systems Interconnection model. A model of network architecture devised by the International Standards Organization (ISO). The OSI model defines seven layers of a network architecture, with each layer performing specified functions. packet. A block of data whose maximum length is fixed. The unit of information exchanged by X.25 at Level 3. There are DATA packets and various control packets. A packet type is identified by the encoding of its header. Packet Exchange Protocol. PXP. A transport layer protocol used in NS3000/XL links to initially establish communication between nodes when NetIPC socket registry is used. packet-switched network name. The name of a data communication network adhering to the CCITT X.25 recommendation. This can be a PDN or a private network, such as the HP PPN. PAD (packet assembler/disassembler). A device that converts asynchronous character streams into packets that can be transmitted over a packet switching network (PSN). PAD name. A name of up to eight characters that is associated with a configured PAD device. The PAD name is known to both the DTC (defined by the DTC Manager) and the MPE XL systems (defined by NMMGR) that the device can access. PAD profile. Terminal or printer profile that specifies the configuration characteristics for PAD-connected devices. partner gateway half. When gateway halves are used, two gateway halves are required in order to provide communication between two networks. Each is the partner of the other. path name. When configuring with NMMGR, you can type a string in the COMMAND: field on display screens to branch to another screen. Each screen has a unique path name that corresponds to its location in the hierarchy of configuration screens presented by NMMGR. PDN. Public data network. A data communication network whose services are available to any user willing to pay for them. Most PDNs use packet switching techniques. point-to-point. A link that connects either two nodes in an NS Point-to-Point 3000/XL network or two gateway halves. port. An outlet through which a device can be connected to a computer, consisting of a physical connection point and controlling hardware, controlling software, and configurable port characteristics. Ports can be thought of as data paths through which a device communicates with the computer. Precision Architecture. The hardware design structure for the 900 Series HP 3000 computer family. printer name. Character string of up to 16 characters specified in the DTC Manager configuration (for networks using OpenView Network Management) to define a printer by name. Can be shared by several printers (port pool). printer profile. A set of configuration characteristics that can be associated with one or more printers through the NMMGR configuration. Printer profile specifications include the printer type, line speed, device class assignment, and other values relevant to printers connected through a DTC. printer type. A collection of characteristics that cause a printer connected to an MPE XL system to act and react in a specified manner. You can configure a printer to use one of the system-supplied printer types, or you can create custom printer types using Workstation Configurator. privileged mode. A capability assigned to accounts, groups, or users allowing unrestricted memory access, access to privileged CPU instructions, and the ability to call privileged procedures. probe protocol. An HP protocol used by NS3000/XL IEEE 802.3 networks to obtain information about other nodes on the network. probe proxy server. A node on an IEEE 802.3 network that possesses a network directory. A probe proxy server can provide a node with information about other nodes on the same or other networks of an internetwork. profile. A method of grouping device connection specifications and characteristics so that the set of characteristics can be easily associated with groups of like devices. See also printer profile, terminal profile. program captive device. See programmatic device. Programmable Serial Interface. PSI. A hardware card that fits into the backplane of the 900 Series HP 3000 computer. It provides a physical layer interface for NS Point-to-Point 3000/XL Links. programmatic device. A device operating under control of a program running on a computer. Programmatic devices can be used for input, output, or both, depending on the device and how it is opened by the controlling program. protocol. A set of rules that enables two or more data processing entities to exchange information. In networks, protocols are the rules and conventions that govern each layer of network architecture. They define what functions are to be performed and how messages are to be exchanged. PSN. Packet-Switching Network. Any data communication network using packet-switching techniques wherein data is disassembled into packets at a source interface and reassembled into a data stream at a destination interface. A public PSN offers the service to any paying customer. PSS. Packet-Switching System. The national public PSN of the United Kingdom. PVC. Permanent Virtual Circuit. A permanent logical association between two physically separate DTEs that does not require call set-up or clearing procedures. PXP. See Packet Exchange Protocol. Q bit. Qualified bit. When set in DATA packets the Q bit signifies that the packet's user data is a control signal for the remote device, not a message for its user. QuickVal. A software program that tests whether Network Services are operating correctly between nodes. RDBA. Remote Data Base Access. A network service that allows users to access data bases on remote nodes. reachable network. A network that can be accessed (with additional internet hops possibly required) by a particular gateway. remote connect device. Asynchronous device that is connected to a DTC indirectly, using a modem and telephone hook-up, or a PAD. remote node. A node on an internetwork other than the node you are currently using or referring to. retransmission count (N2). The maximum number of times a frame will be retransmitted following the expiration of the Retransmission Timer, T1. retransmission timer (T1). Length of time the transmitter will wait for an acknowledgment from the destination address before attempting to retransmit the frame. When choosing this value, factors like the line speed and maximum frame size should be taken into account. RFA. Remote File Access. A network service that allows users to access file and devices on remote nodes. router network. See point-to-point. routing. The path that packets, or fragments of a message, take through a network to reach a destination node. RPM. Remote Process Management. A network service that allows a process to programmatically initiate and terminate other processes throughout a network from any node on the network. RS-232-C. Electronic Industries Association (EIA) Level 1 protocol specification that defines electrical circuit functions for 25 connector pins. HP provides two implementations of this standard: a 3-pin version for direct connections up to a distance of 15 meters (50 feet), and a version which makes use of additional circuits and can be used for either modem or direct connections. RS-422. Electronic Industries Association (EIA) Level 1 protocol specification implemented by HP in a 5-pin version which can be used for direct device connection up to a distance of 1500 meters (4000 feet). security string. An alphanumeric character string that functions as a password for dial links. The security string is used by the Dial IP protocol. serial device. Any device that is attached to and communicates with a computer by means of a serial transmission interface. Terminals, printers, and plotters are among the devices that communicate serially with MPE XL computers. serial transmission. Method of transferring data in which characters are transmitted one bit at a time and received one bit at a time in the order of transmission. This transmission scheme is employed by devices connected to the MPE XL systems via the DTC. session-accepting device. A terminal or personal computer running in terminal-emulation mode that is able to establish an interactive (conversational) session with an HP 3000 computer. Also referred to as a logon device. shared dial. A dial link that provides connection to more than one remote system, although to only one at a time. shared-line access. Feature that allows two or more 900 Series HP 3000 hosts to use the same DTC/X.25 Network Access card on a DTC to access an X.25 network. SIC. Serial Interface Card. Card installed in the front of the DTC that acts as an interface between a corresponding Connector Card (CC) and the DTC's processor. slaved device. A device that shares the same DTC port as another device and is connected, to the other device, referred to as its master, by a cable. The actions of the slaved device are controlled by the master device. spooled device. A printer that is accessed through the MPE XL spooling facility. The spooling facility allows a nonsharable device to be shared among several users by temporarily storing output data on disc and managing the selection of output spool files destined for the spooled device. start bit. Data bit used to signal the start of a character being transmitted in an asynchronous communication mode. station address. A link-level address used by the IEEE 802.3 protocol that is assigned to every node on an IEEE 802.3 network. stop bit. Data bit used to signal the end of a character being transmitted in an asynchronous communication mode. store-and-forward. A technique in which messages are passed from one node to another in a network to reach their destination. Point-to-point networks use the store-and-forward technique to transmit messages. subnet. Another name for a network, especially if the network is part of an internetwork. The word subnet is also a synonym for intranet. SVC. Switched Virtual Circuit. Path through an X.25 network that is established at call set-up time. switching. See DTC switching. Switching User Interface. User interface available when DTC switching is enabled that allows terminal users to choose the MPE XL computer with which they want to establish a communication link. synchronous. A mode of operation or transmission whereby a continuous data stream is generated without intervals between characters. The data stream is synchronized by clock signals at the receiver and transmitter. As a result, fast transmission speeds (above 9600 bps) are attainable. SYSGEN. The software program that allows you to configure the operating system on 900 Series HP 3000 computers. system configuration. The way you tell MPE XL what peripheral I/O devices are attached to the DTC and what parameters are required for system operation. TCP. See Transmission Control Protocol. Telenet. A proprietary public data network in the USA. TermDSM. Terminal Online Diagnostic System Manager. A utility that provides diagnostic services for DTC connections by means of a series of commands accessible through the SYSDIAG utility. TermDSM is used only when DTCs are managed by an MPE XL host system. terminal name. Character string of up to 16 characters specified in the Openview dtc Manager configuration (for networks using OpenView Network Management to define a terminal by name. May be shared by several terminals (pool port). terminal profile. A set of configuration characteristics that can be associated with one or more terminals through the NMMGR configuration. Terminal profile specifications include the terminal type, line speed, device class assignment, and other values relevant to terminals connected through a DTC. terminal type. A collection of characteristics that cause a terminal connected to an MPE XL system to act and react in a specified manner. You may configure a terminal to use one of the system-supplied terminal types, or you may create custom terminal types using the Workstation Configurator. ThinLAN 3000/XL. A LAN that conforms to the IEEE 802.3 Type 10 BASE 2 standard LAN. throughput class. A value assigned to a given virtual circuit that defines how many network resources should be assigned to a given call. It is determined by the access line speed, packet and window sizes, and the local network's internal mechanisms. throughput class negotiation. One of the Network Subscribed Facilities defined at subscription time. This allows the user to negotiate the Throughput Class at call set-up time. timer (T3). Length of time that a link can remain in an idle state. After the expiration of the timer, the link is considered to be in a non-active, non-operational state and is automatically reset. The value should be chosen carefully. In particular, it must be sufficiently greater than the Retransmission Timer (T1) so that no doubt exists about the link's state. topology. The physical arrangement of nodes in a network. Some common topologies are bus, star, and ring. Transmission Control Protocol. TCP. A network protocol that establishes and maintains connections between nodes. TCP regulates the flow of data, breaks messages into smaller fragments if necessary (and reassembles the fragments at the destination), detects errors, and retransmits messages if errors have been detected. Transpac. The national public PSN of France. transparent mode. Data transfer scheme in which only a limited number of special characters retain their meaning and are acted on by the system. All other characters are considered to be data and are passed through with no control actions being taken. transport, network. Software that corresponds to layers 4 and 3 of the OSI network architecture model. The function of this software is to send data out over the appropriate communications link, to receive incoming data, and to route incoming or outgoing data to the appropriate destination node. Tymnet. A proprietary public data network in the USA. typeahead. A facility that allows terminal users to enter data before a read is actually posted to the terminal. unacknowledged frame number (K). The number of frames that can be transmitted without receiving an acknowledgement from the destination address. When this number (K) frame is reached, the same K frames are retransmitted. unedited mode. See transparent mode. V.24. The CCITT recommendation that defines the function of the interchange circuits between a DTE and a DCE. validation. The process of ascertaining whether the network transport configuration file has been correctly configured. In guided NMMGR, you do this by pressing the Validate Netxport key. VAN. Value-Added Network. A data communication network that uses and pays for facilities belonging to another carrier. The value-added package is then sold to a user. VC. See virtual circuit. virtual circuit. A logical association between two physically separate DTEs. Virtual Terminal. A network service that allows a user to establish interactive sessions on a node. VPLUS. Software used to generate screens such as those displayed by NMMGR. V-Series (V.##) CCITT. A set of CCITT recommendations related to data communication over a voice-grade telephone network. VT. See Virtual Terminal. Workstation Configurator. A utility available on MPE XL systems that allows users to create customized terminal and printer types by entering data through a series of VPLUS screens. X.3. Defines the user facilities that should be internationally available from the packet assembler/disassembler (PAD) facility when this is offered by a public data network. X.21. Defines the physical interface between a DTE and a DCE of a public data network where the access to the network is made over synchronous digital lines. X.25. Defines the interface between a DTE and a DCE for packet mode operation on a Public Data Network (PDN). X.25 address. The X.25 address provided by the network administration if you are connected to a Public Data Network (PDN). X.25 address key. An X.25 address key is a label that maps a node's IP address to its X.25 address and its associated X.25 parameters. You have a combined maximum of 1024 X.25 address keys in the SVC and PVC path tables X.25 LUG address. X.25 address of a node belonging to a LUG. X.25 XL System Access. The software that works in conjunction with the DTC/X.25 Network Access software to provide MPE XL access to X.25. The software resides on an HP 3000 host and is configured through use of NMMGR. To configure access to an X.25 network, you must configure two software components: the X.25 XL System Access, and the DTC/X.25 Network Access (residing on the Datacommunications and Terminal Controller and configured at the OpenView Windows Workstation). Together, these two components provide a network connection on HP 3000 systems to private and public X.25 packet-switched networks PSNs. X.29. Defines the interface for data exchange between a packet-mode DTE and a remote Packet Assembly/Disassembly (PAD) facility over a packet switching network. XON/XOFF protocol. Flow control used by MPE XL systems to protect against data overruns. XON/XOFF protocol is controlled by the data recipient who sends an XOFF character (ASCII DC3) to the sender if it is unable to continue to receive data. The sender suspends transmission until it receives an XON character (ASCII DC1). X.Series (X.##) CCITT recommendations. A set of recommendations for data communication networks governing their services, facilities, and the operation of terminal equipment and interfaces.