HP ProCurve Secure 7000dl Series Basic Management And Configuration Manual page 762

Appendix B: Glossary
NT1 Network Termination 1. A device at the physical and electrical termination of
NT12 Network Termination 1 2. A device that functions as both an NT1 and an NT2
NT2 Network Termination 2. A device required for PRI ISDN. The NT2 provides
NVRAM Non-Volatile Random Access Memory. A data-storage medium that retains
OAM Operations, Administration, and Maintenance. OAM ATM cells are sent over
OC-1 Optical Carrier-1. In the Synchronous Digital Hierarchy, OC-1 is the base
OC-N Optical Carrier Level N. The fundamental transmission rates for SONET,
OCU Office Channel Unit. A Central Office (CO) device that is used for direct
OCUDP Office Channel Unit Data Port. A CO device that provides signal conversion
Option Parameters or variables supported by a protocol. For example, the PPP LCP
OS Operating System. A system of software that performs basic tasks, such as
B-36
the ISDN line. The NT1 monitors the line, maintains timing, and provides
power to the ISDN line. This device is purchased and maintained by the
subscriber.
device.
switching functions and manages traffic across the multiple B channels.
memory when powered down.
O
a VCI to maintain the link. OAM cells are divided into five levels, and the
functions of each level are separate from those of each other level. See also
F5 OAM.
multiple for SONET systems and transmits as 51.84 Mbps.
where N=1 (51.84 Mbps), 3 (155.52 Mbps), 12 (622 Mbps), 24 (1.244 Gbps), 48
(2.488 Gbps) or 192 (9.953 Gbps).
handling of 56K and 64K DDS services. The OCU is usually a special card
incorporated into multiplexers at the CO.
from the transmission rates on the customer side of the local loop to a single
DS0 time slot. It provides the interface between Switched 56/64K or DDS
interfaces and the telecom infrastructure.
protocol includes options for whether or not peers will use LQR, magic
numbers, protocol-field compression, address and control field compression,
or an authentication protocol. The MRU option specifies the maximum size
for packets sent over the connection.
recognizing input from the keyboard, sending output to the display screen,
keeping track of files and directories, and controlling peripheral devices. For