Comtech EF Data SLM-5650A Vipersat - Manual (Page 145)

Appendix D - Glossary D-7
N
NAT Network Address Translation – An Internet standard that enables a LAN to use
one set of IP addresses for internal (private) traffic and a second set of addresses
for external (public) traffic.
NIC Network Interface Controller – The network interface for a PC/workstation that
provides Ethernet connectivity. Depending on the computer, the NIC can either
be built into the motherboard, or be an expansion card. Some computers (e.g.,
servers) have multiple NICs, each indentified by a unique IP address.
NMS Network Management System
NOC Network Operations Center – The main control center for network operations.
A NOC can interrogate, control, and log network activities for the satellite Hub
as well as any Remote node.
NP Network Processor – Also referred to as the IP Module. An optional assembly
for Comtech EF Data modems that provides the 10/100 BaseT Ethernet inter-
face that is required when used in Vipersat networks.
O
ODU Outdoor Unit – In a VSAT system, the RF components (transceiver) are usually
installed outdoors on the antenna structure itself and are thus referred to as an
ODU. The ODU typically includes the BUC and LNB, and is connected to the
IDU/modem by the IFL cabling.
OQPSK Offset Quadrature Phase Shift Keying – A variant of phase-shift keying using
four different values of the phase to transmit. Offsetting the bit timing limits the
phase shift and yields lower amplitude fluctuations as compared to QPSK, and
is sometimes preferred for communications systems. See also QPSK and BPSK.
OSPF Open Shortest Path First – An open standard interior gateway routing protocol
used to determine the best route for delivering the packets within an IP network.
OSPF routers use the Shortest Path First link state algorithm to calculate the
shortest path to each node in the network. The Vipersat OSPF feature in the
Comtech SLM-5650A modem/router provides for dynamic routing functional-
ity.