Multi-Tech Systems MTA128NT - Manual (Page 62)

Glossary
MTA128ST/NT 62
compressed in a secure manner before being encrypted with a
private (secret) key under public-key cryptisystem.
MLPPP (Multilink Point-to-Point Protocol, also the PPP Multilink
Protocol or MP)—is an Internet standards track protocol for a
methyod of splittingm recombining, and sequencing datagrams
across multiple logical data links, giving you additional bandwith-
on-demand. Originally, MLPPP was used to combine two ISDN BRI
channels into a single high-speed data path, but now is also used
anywhere multiple PPP links connect two systems, including async
links. This is done with new PPP options and protocols. Also knows
as MPPP and PPP Multilink, MLPPP is an effective means of
bonding channels for providing bandwith-on-demand.
modem—A communications device that enables a computer to
transmit information over a telephone line. It converts the
computer’s digital signals into analog signals to send over a tele-
phone line and converts them back to digital signals at the receiving
end. Modems can be internal and fit into an expansion slot, or
external and connect to a serial port.
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 previ-
ously switched circuit or circuits.
nailed-up circuit—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.
NI-2 (National ISDN-2)—A physical standard subsequent to NI1.
When tested and deployed, NI-2 will provide additional features and
enhanced plug and play capabilities.
node—Any point within a network that has been assigned an
address.
NT (network termination)—Devices that form the boundary be-
tween customer premise equipment and telephone company equip-
ment. Two types of NTs are used: NT1 and NT2.
NT1 (Network TerminationType 1)—An interface device used in the
BRI portion of ISDN to connect four-wire (S/T) ISDN devices to
the two-wire (2BIQ U) IDN. It provides basic rate access in a 2B+D
format with two 64 bps channels for voice, data, and video commu-
nications. It also provides one 16 Kbps channel for packet-mode
signalling, low-speed data and telecommunications services at the
OSI Layer 1 level. Similar in function to a DSU/CSU device.
NT2 (Network TerminationType 2)—A device at the customer
premise (user) side responsible for the ISDN network connection
and for functions such as multiplexing and switching (may be an
intelligent device).
NTE (network terminating equipment)—A set of ISDN functions
residing at the boundary of the IDN and the subscriber.
NUI (network user identification)—A unique alphanumeric number
provided to dial-up users to identify them to packet-switched net-
works world-wide. The number is used for network access and
billing.
O
off-hook—The condition of a device that has accessed a phone line
(with or without using the line). In modem use, this is equivalent to
a telephone handset being picked up. Dialing and transmission are
allowed, but incoming calls are not answered.
on-demand dialing—A cost-saving feature of ISDN that sets up,
transfers, and then closes a call only when the ISDN device detects a
data packet addressed to the remote network, but will not perform
setup/transfers of just administrative (non-user data) packets.
out-of-band signaling—A system that uses a separate communica-
tions channel or frequency outside the voice band for signaling.
Modern systems use a separate channel, either TDM or virtual. SS7
uses messages for signaling that are carried on signaling links
distinct from voice channels. ISDN uses messages for signaling that
are carried on the
D-channel distinct from the voice carried on the B-channels. Frame
Relay and ATM use messages that are carried on a separate virtual
connection reserved for signaling.
on-hook—The condition of a device which has not accessed a
phone line. In modem use, this is equivalent to a telephone handset
that has not been picked up. In other words, it can receive an incom-
ing call.
P
packet data—Packet-mode calls.
packet mode—The switching of chunks of information for different
users using statistical multiplexing to send them over the same
transmission facility. ISDN packet mode capabilities are based on
the ITU-TSS Recommendation X.25 procedures.
PAP(Password Authentication Protocol): (RFC1334)
parity bit—An extra bit attached to each byte of sync—hronous
data used to detect errors in transmission.
PBX (private branch exchange)—A telephone exchange located on
the customer’s premises. The PBX provides a circuit switching
facility for tlephone extension lines within the building, and access
to the public telephone network. See also exchange.
P-channel (PCHAN)—The ISDN physical channel identification;
contrast logical channel or virtual channel.
PDN (public data network)—A packet-switched network that is
available to the public for individual (subscriber) use. Typically,
controlled by a government or a national monopoly.
port—A location for input or output data exchange. Computers,
muxes, etc. have ports for various purposes.
PPP (Point to Point Protocol)—A protocol that lets a computer user
access a TCP/IP address using an ISDN terminal adapter or a high-
speed modem over a standard telephone line.
PRI (Primary Rate Interface)—One
of two forms of ISDN service. PRI provides 23 64 Kbps B-channels
for video, voice or data, and one 64 Kbps D-channel for control