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Operations, Administration, Management (and Provisioning)
refer to ATM-specific diagnostic flows used to test/troubleshoot
OC The optical specification over SONET. An OC level is the
optical equivalent of an STS signal. Transmission rates are
based on 51.84 Mbps (OC-1). A c following an OC level
identifies concatenation of payload (for example, OC-3c).
Open Datalink Interface Protocol-independent Novell specification
providing standardized access to networks; allows multiple
network interface card device drivers and
protocols to share a single network interface card without
Open Systems Interconnection (OSI) Program created by the
ISO and CCITT (now ITU-T) for developing international standards
for data networking.
Open Shortest Path First (OSPF) An interior gateway protocol
that routes messages according to the shortest and least expensive
path. OSPF was developed to replace RIP.
Open Systems Interconnection (OSI) reference model A seven-layer
model for data communication that is the standard network
architecture developed by the International Organization for
Standardization (ISO). The layers are as follows: physical,
data-link, network, transport, session, presentation, and
Packet Burst The technology used in NetWare networks that
allows clients and servers to transmit multiple packets of
information without requiring a response to each packet, thus
reducing local and wide area network traffic.
Packet-switching network A network that transmits
messages by dividing them into individual packets, routing
them randomly over the best available connection, and then
reassembling them to form the complete message at the destination.
Most modern WAN protocols, including TCP/IP,
X.25, and frame relay, are based on packet-switching technologies.
Peer-to-peer network A network in which each node (computer)
has equivalent client and server capabilities. In a peer-to-peer
network, communication and data sharing occurs
directly between nodes, rather than through an intermediary
Permanent virtual circuit (PVC) A continuously available communications
path that connects two fixed end points. A PVC is similar
to a leased line.
Physical layer The first of seven layers of the OSI model,
the physical layer puts data onto and removes data from the
Physical topology The physical layout of a network's guided
transmission media (usually network cabling). The most common
physical topologies are the bus, the star, and the star-wired
Pluggable Authentication Module (PAM) A login framework used
by system entry components to authenticate users to a UNIX
Point of Presence (POP) The location of an access point to
the Internet. A POP necessarily has a unique IP address. An
Internet Service Provider or online service has a point of
presence on the Internet. The number of POPs that an ISP or
OSP has is sometimes used as a measure of its size or growth
Point-to-Point Protocol (PPP) The communications protocol
a computer uses to make TCP/IP connections with a regular
telephone line and a modem.
Point-to-Point Remote Node Service (PPPRNS) A service that
provides PPP support for remote DOS and Windows clients that
are using Internetwork Packet Exchange (IPX) software or Internet
Point-to-Point Tunneling Protocol (PPTP) A technology used
to create virtual private networks. PPTP ensures that messages
transmitted from one VPN node to another are secure.