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A hardware device that transmits packets between networks. A bridge forwards packets from one network to another, and discards packets destined for hosts on the sending network. Operating at the Data Link layer, a bridge makes multiple networks look like a single network to higher-level protocols and software.
A table that contains entries pairing up a host's Media Access Control (MAC) address with a particular Ethernet interface. If the MAX receives a packet whose destination MAC address is not on the local network, it first checks its bridging table. If it find the packet's destination MAC address, the MAX dials the connection and bridges the packet. If it does not find the address, the MAX checks for active sessions that have bridging enabled. If one or more active bridging links are up, the MAX forwards the packet across all active sessions that have bridging enabled.
The process of sending a message to all connected hosts, as opposed to sending a message to a single host or to members of a multicast group.
A password that the MAX sends to the Simple Network Management Protocol (SNMP) manager when an SNMP trap event occurs, and that the manager sends to the MAX with each polling request. The password authenticates the sender. The default is
public.Graphical device in NavisConnect for displaying and changing Ascend products' configuration parameters.
A local profile containing authentication and configuration information about a remote device or user.
Dynamic Bandwidth Allocation. DBA denotes the process of adding or subtracting bandwidth from a switched connection in real time without terminating the link.
In NavisConnect, the left-hand side of the Explorer window and configuration window. Displays information about the Ascend unit and its configuration.
The most commonly used architecture for Local Area Networks (LANs), connecting devices such as computers, printers, and terminals. An Ethernet network uses the Physical and Data Link layers for data transmission. Ethernet incorporates a bus topology, and can operate at a rate of up to 10 Mbps.
NavisConnect tool for connecting to an Ascend unit and loading and displaying its parameters. It provides access to the NavisConnect QuickStart program and Syslog, a UNIX-based system activity log.
A set of rules describing what action the MAX should take when it encounters certain types of packets. A filter can apply to incoming packets, outgoing packets, or both.
A profile containing parameters that set up filter rules.
A WAN architecture originally developed for ISDN lines. A Frame Relay network provides high throughput by handing monitoring functions to higher-level protocols. It is a very efficient standard, with a bandwidth of up to 2 Mbps. Frame Relay is ideal for situations in which periods of very high traffic are interspersed with idle periods. It is protocol independent, and performs routing over virtual circuits called Data Link Connection Indicators (DLCIs).
ANSI standards T1.606 and T1.618 define the procedures for handling data frames at a Frame Relay network node. ANSI standard T1.617 specifies maintenance procedures for a Frame Relay network.
A profile that defines the logical link between the MAX and a Frame Relay switch.
Internet Protocol. IP provides connectionless, nonguaranteed transmission of Transport-layer data packets. IP fragments packets, allowing them to take different paths across the WAN, and then reassembles them into the proper order at their destination.
Internetwork Packet Exchange. IPX is Novell's connectionless Network-layer protocol. Derived from the XNS Internetwork Datagram Protocol (IDP), IPX performs addressing and routing functions. At the server, IPX passes outgoing datagrams to the network interface software. At the packet's destination, IPX passes the data to upper-layer processes. Along an IPX route, intermediate devices use IPX to route packets to their destinations. When routing, IPX relies on information supplied by the Routing Information Protocol (RIP).
An address that uniquely identifies each host on a network or internet. An IP address has a length of 32 bits, and is divided into four 8-bit parts, each separated by a period, as in 149.122.3.30. This kind of notation is called dotted decimal notation. Each part can consist of a number from 1 to 255.
An IP address consists of a network number and a host number. IP addresses can be of three types: Class A, Class B, and Class C. The class of an IP address determines which portion of the address belongs to the network number and which portion belongs to the host number. The first bits of the IP address identify the class. The Internet Network Information Center (InterNIC) determines the type of class assigned a network.
A portion of an IP network. IP subnetting is a method of subdividing a network into smaller networks, resulting in a greater number of hosts on a network associated with a single IP network number. An IP address that uses a subnet has three elements: network, subnet, and host. You identify a subnet by combining an address with a subnet mask. For example, in the address 195.112.56.75/14, /14 is the subnet mask, indicating that the first 14 bits of the address identify a subnet.
An object-oriented programming language developed by Sun Microsystems, Inc. You can use Java to create applets for distribution on the World Wide Web. Java programs run inside a Java-enabled Web browser or inside a Java Virtual Machine (JVM).
Java Virtual Machine. A JVM is an abstract computer that runs compiled Java code. The JVM is virtual because it is software that runs on top of a hardware platform and an operating system. All Java programs are compiled for a JVM.
Local Area Network. A LAN is a network in which two or more computers, located within a limited distance of one another, are connected in order to share files and resources. A PC-based LAN consists of a dedicated server running a network operating system and attached to several workstations. A host-based LAN consists of one or more hosts and terminals. Examples of LAN architectures are Ethernet, ARCnet, Fiber Distributed Data Interface (FDDI), and Token Ring.
The 6-byte hexadecimal address that the manufacturer assigns to the Ethernet controller for a port. The MAC address is also called an Ethernet address.
An application that receives Simple Network Management Protocol (SNMP) information from an agent. An agent and manager share a database of information, called the Management Information Base (MIB). An agent can use a message called a traps-PDU to send unsolicited information to the manager. A manager that uses the Ascend Enterprise MIB can query the MAX, set parameters, sound alarms when certain conditions appear, and perform other administrative tasks.
A multiprotocol WAN access router designed for central-site remote-access applications. The MAX offers the following features:
In the NavisConnect Explorer, a navigation device for loading parameters from Ascend units and configuration files in the Explorer. In the Configuration window, a similar device is used for accessing profiles and setting groups.
An application that delivers superior management for the dial-up and dedicated portions of the network, providing extensive support for discovery and mapping, configuration, fault and performance management, and security.
A management tool for True Access Operating System-enabled devices, including the MAX 800. NavisConnect has a graphical user interface that can be used for installing and configuring Ascend devices.
Nonvolatile Random Access Memory. NVRAM is a type of memory that maintains its data contents across resets and power cycles. It is useful for storing configuration information across sessions. Data is written and erased in blocks, rather than byte-by-byte.
The MAX unit's system configuration is stored in the onboard NVRAM. Some error conditions might require that you clear the MAX configuration and reboot. When you clear NVRAM, the system is reinitialized and comes up unconfigured, just as it was when you first installed it. You can then restore the configuration from a recent backup.
Credit-card sized computer enhancement hardware with specifications defined by the PCMCIA. Also called PC card.
The Personal Computer Memory Card International Association, a nonprofit trade and standards association that establishes and maintains the PCMCIA card specifications.
See PCMCIA card.
A high-performance WAN router enabling Internet users access to corporate FTP sites, World Wide Web sites, and other publicly available resources, while permitting internal users secure access to the corporate network backbone. The Pipeline 220 delivers WAN access through either an unchannelized T1/FT1 or a V.35 interface.
Power-On Self Test. A POST is a diagnostic test the MAX performs when it first starts up or after it completes a system reset. During a POST, the MAX checks system memory, configuration, installed cards, compression hardware, and T1 connections.
A collection of settings that enable you to configure various aspects of an Ascend product. For example, a Connection profile enables you to specify the name, password, and network resources for a dial-in caller.
A set of rules governing message exchange over a network or internet. Examples of commonly used protocols are Transmission Control Protocol/Internet Protocol (TCP/IP), Point-to-Point Protocol (PPP), and Internetwork Packet Exchange (IPX).
A NavisConnect tool, accessed through the Configuration window, for performing preliminary configuration on a new unit or adding new slot cards to existing units.
Remote Authentication Dial-In User Service. Using RADIUS, end users can have access to secure networks through a centrally managed server. RADIUS provides authentication for a variety of services, such as login, callback, Serial Line Internet Protocol (SLIP), and Point-to-Point Protocol (PPP). It also enables you to set up accounting. You can keep records of the number of packets the MAX transmitted and received, the protocol in use, the user name and IP address of the client, and other system information.
The machine on which the RADIUS daemon is running. A single RADIUS server can manage multiple security systems, maintaining profiles for thousands of users.
Routing Information Protocol. RIP is a distance-vector protocol found in both the NetWare and TCP/IP protocol suites. The protocol keeps a database of routing information that it gathers from periodic broadcasts by each router on a network.
IPX routers broadcast RIP updates periodically and when a WAN connection is established. The MAX receives IPX RIP broadcasts from a remote device, adds 1 to the hop count of each advertised route, updates its own RIP table, and broadcasts updated RIP packets on connected networks in a split-horizon fashion.
A table that contains information about how to forward IP packets.
A profile that consists of parameters you can set to control access to the MAX.
The state a connection reaches when two parties can communicate with each other.
An installer for NavisConnect.
Simple Network Management Protocol. SNMP is a standard way for computers to share networking information.
In SNMP, two types of communicating devices exist: agents and managers. An agent provides networking information to a manager application running on another computer. The agent can be polled by the manager, and can also use a message called a traps-PDU to send unsolicited information to the manager when an unusual event occurs. The MAX is an example of an SNMP agent. The agents and managers share a database of information, called the Management Information Base (MIB).
The MAX supports SNMP MIB II, T1 MIB, and Ascend Enterprise MIBs. A manager that uses the Ascend Enterprise MIB can query the MAX, set parameters, sound alarms when certain conditions appear, and perform other administrative tasks. You can therefore manage the MAX from a central SNMP manager, such as SunNet Manage or HP Open View.
SNMP security uses the community name that the manager sends (with each polling request) and that the agent sends (with each traps-PDU). Ascend supports two community names: one with read-only, and the other with read/write, access to the MIB.
An IP feature in which a group of bits identifies a subnet. To specify a subnet mask, the MAX appends to the IP address a modifier that specifies the total number of network bits in the address.
A facility that sends system status messages to a host computer, known as the Syslog host. The Syslog host saves the system status messages in a Syslog file. For detailed information about the
syslog daemon, see the UNIX man pages for logger(1), syslog(3), syslog.conf(5), and syslogd(8). The Syslog function requires User Datagram Protocol (UDP) port 514. The station to which the MAX sends system logs.
A protocol that links two computers to provide a terminal connection to the remote machine. Instead of dialing into the computer, you connect to it over the Internet by means of Telnet. When you issue a Telnet session, you connect to the Telnet host and log in. The connection enables you to work with the remote machine as though you were a terminal connected to it. You can remotely manage your Ascend unit by establishing a Telnet session to the unit from any Telnet workstation on the network.
A terminal connection to a remote machine by means of the Telnet protocol. After you set up a basic IP configuration for the Ascend unit, users can Telnet into the unit. Each user can initiate a Telnet session to the Ascend unit from a local workstation or from a WAN connection. In both cases, the Ascend unit authenticates the session. In addition to the Ascend unit password, you can specify that Telnet requires its own password authentication, which occurs prior to any Ascend unit authentication.
A computing device to which a terminal can connect over a LAN or WAN link. A terminal communicates with the terminal server over an asynchronous serial port (typically an RS-232 port) through a modem. A terminal converts the data it receives from the terminal server into a display and does no further processing of the data. A terminal also converts the operator's keystrokes into data for transmission to the terminal server.
Trivial File Transfer Protocol. TFTP is a simple file transfer protocol that depends on UDP.
User Datagram Protocol. UDP is a Transport-layer protocol that provides connectionless service without packet acknowledgment.
A16-bit number that allows multiple processes to use User Datagram Protocol (UDP) services on the same host. A UDP address is the combination of a 32-bit IP address and the 16-bit port number. Examples of well-known UDP ports are 7 (for Echo packets), 161 (for SNMP packets), and 514 (for Syslog packets).
An ASCII-character data terminal, consisting of a screen and keyboard. Manufactured by Digital Equipment Corporation (DEC), the VT100 has become an industry standard data terminal. VT100-emulation software allows a standard PC to act as a VT100 terminal.
Wide Area Network. A WAN is an internet of devices, generally consisting of several networks distributed over a wide geographic distance, connected by telephone lines, and using different hardware platforms and protocol encapsulation.
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