Multi Tech Equipment MTA128ST manual PPPMultilink Protocol or MP-is an Internet

Glossary

organization that prepares standards for resolving communications issues and problems.

L

LAPB (Link Access Procedure Balanced)—Based on the X.25 Layer 2 specification. A full-duplex, point- to-point, bit-synchronous protocol commonly used as a data link control protocol to interface X.25 DTEs.

LAPB is the link initialization procedure that estab- lishes and maintains communications between the DTE and the DCE.

LAPD (Link Access Protocol for the

D-Channel)—Based on the ISDN Q.921 specification. A full-duplex point-to-point bit-synchronous link-level protocol for ISDN connections; different from LAPB in its framing sequence. Transmission is in units calledframes, and a frame may contain one or more X.25

packets.

link optimization—An ISDN feature that permits only user data to open the communications link and keeps administrative packets from opening the link. A cost saving feature that ensures that remote connections are not unnecessarily utilized.

local loop—A transmission path, typically twisted- pair wire, between an individual subscriber and the nearest public telecommunications network switching center. Also called the subscriber loop.

LT (loop termination)—A device, similar to an NT1, that terminates the local loop at the carrier’s central switching office. The LT provides the interface to the ISDN U reference point. Contrast ET (exchange termination).

MP+(MultiLink Protocol Plus)—An extension to the PPP Multilink Protocol (MP) convered in IETF RFC 1717. MP+ is a new control protocol for managing multiple data links that are bundled by MP. Also called the Multichannel Protocol Plus or MPP.

MS-CHAP—Microsoft version of CHAP.

multilink—In point-to-point protocol, literally many links. A procedure used to route data packets over many links for increased bandwidth (e.g., two B-channels on a single BRI for 128 Kbps).

mux (multiplexer)—A device that merges several signals into one composite signal for transmission over a single medium or channel. A demultiplexer, built into most muxes, reverses the process at the receiving end.

N

nailed connection—A permanent or dedicated circuit of a previously switched circuit or circuits.

nailed-upcircuit—A semi-permanent circuit established through a circuit-switching facility for point-to-point connectivity.

NAK (negative acknowledgment)—A communications code used to indicate that a message was not properly received, or that a terminal does not wish to transmit. Contrast with ACK.

network—A group of computers connected by cables or other means and using software that enables them to share equipment, such as printers and disk drives to exchange information.

NI-1(National ISDN-1)—A physical standard to make all compliant ISDN lines appear the same. With ISDN-1 installed, additional costs are not incurred when changing from prestandard ISDN to standard ISDN. Most RBOCs now are moving to ISDN-1.

M	NI-2(National ISDN-2)—A physical standard subsequent to
MD5(MD5 Message-Digest Algorithm)—Takes a	NI1. When tested and deployed, NI-2 will provide additional
	features and enhanced plug and play capabilities.
message if arbitrary length as input and produces it
as output as a 128-bit fingerprint or message digest	node—Any point within a network that has been
of the input. The MD5 algorithm is used for digital	assigned an address.
signature applications where a large file must be	NT (network termination)—Devices that form the boundary
compressed in a secure manner before being	between customer premise equipment and telephone
encrypted with a private (secret) key under	company equipment. Two types of NTs are used: NT1 and
public-key cryptisystem.	NT2.
MLPPP (Multilink Point-to-Point Protocol, also the	NT1 (Network TerminationType 1)—An interface device used
PPPMultilink Protocol or MP)—is an Internet	in the BRI portion of ISDN to connect four-wire (S/T) ISDN
standards track protocol for a methyod of splittingm	devices to the two-wire (2BIQ U) IDN. It provides basic rate
recombining, and sequencing datagrams across	access in a 2B+D format with two 64 bps channels for voice,
multiple logical data links, giving you additional	data, and video communications. It also provides one 16 Kbps
bandwithon-demand. Originally, MLPPP was used to	channel for packet-mode signalling, low-speed data and
combine two ISDN BRI channels into a single high-	telecommunications services at the OSI Layer 1 level.
speed data path, but now is also used anywhere	Similar in function to a DSU/CSU device. NT2 (Network
multiple PPP links connect two systems, including	TerminationType 2)—A device at the customer premise
async links. This is done with new PPP options and	(user) side responsible for the ISDN network connection and
protocols. Also knows as MPPP and PPP Multilink,	for functions such as multiplexing and switching (may be an
MLPPP is an effective means of bonding channels for	intelligent device).
providing bandwith-on-demand.	NTE (network terminating equipment)—A set of ISDN
modem—A communications device that enables a	functions residing at the boundary of the IDN and the
computer to transmit information over a telephone	subscriber.
line. It converts the computer’s digital signals into	NUI (network user identification)—A unique alphanumeric
analog signals to send over a telephone line and	number provided to dial-up users to identify them to packet-
converts them back to digital signals at the receiving	switched networks world-wide. The number is used for
end. Modems can be internal and fit into an	network access and billing.
expansion slot, or external and connect to a serial	O
port.
MTA128ST/NT	56