NETGEAR ProSafe GSM7224 User Manual page 221

User Manual for the NETGEAR 7200 Series Layer 2 Managed Switch Software
nm
Nanometer (1 x 10e ) meters.
9
non-stub area
Resource-intensive OSPF area that carries a default route, static routes, intra-area routes, interarea routes,
and external routes. Non-stub areas are the only OSPF areas that can have virtual links configured across
them, and are the only areas that can contain an ASBR. Compare with stub area. See also ASAM and OSPF.
(Cisco Systems Inc.)
O
Open Systems Interconnection
OSI is a seven (7) layer architecture model for communications systems developed by the ISO for the
interconnection of data communications systems. Each layer uses and builds on the services provided by
those below it.
OSI
See "Open Systems Interconnection" on page 13.
P
packet
A block of information sent over a network. A packet typically contains a source and destination network
address, some protocol and length information, a block of data, and a checksum.
PDU
See "Protocol Data Unit" on page 14.
PHY
The OSI Physical Layer: The physical layer provides for transmission of cells over a physical medium
connecting two ATM devices. This physical layer is comprised of two sublayers: the Physical Medium
Dependent (PMD) sublayer, and the Transmission Convergence (TC) sublayer.
Point-to-Point Protocol
PPP. A protocol allowing a computer using TCP/IP to connect directly to the Internet.
Port Mirroring
Also known as a roving analysis port. This is a method of monitoring network traffic that forwards a copy of
each incoming and outgoing packet from one port of a network switch to another port where the packet can
be studied. A network administrator uses port mirroring as a diagnostic tool or debugging feature, especially
Glossary C-13
202-10009-01_060204