User Manual

User’s Guide Glossary
M
MAC (Media Access Control) The unique
hardware number of a device connected to a
shared media. On an Ethernet it is the same
interface as the Ethernet address.
metric A concept used to describe the cost of a
route across a network, the distance to the
destination at the remote end of the route, or
the capacity of the route.
MIB A management information base (MIB) is
a formal description of a set of network objects
that can be managed using the Simple
Network Management Protocol (SNMP). There
are MIBs (or more accurately, MIB extensions)
for each set of related network entities that can
be managed.
N
name resolution The process of mapping a
name into the corresponding address. See
DNS.
NAT Network Address Translation, an Internet
standard that enables a local-area network
(LAN to use one set of IP addresses for
internal traffic and a second set of addresses
for external traffic. A NAT box located where
the LAN meets the Internet makes all
necessary IP address translations. NAT is
used for two main tasks – to provide a type of
firewall by hiding internal IP addresses and
enable a company to use more internal IP
addresses. Since they're used internally only,
there's no possibility of conflict with IP
addresses used by other companies and
organizations.
network A computer network is a data
communications system, which interconnects
computer systems at various different sites. A
network may be composed of any combination
of LANs or WANs.
network address The network portion of an IP
address. For a class A network, the network
address is the first byte of the IP address. For
a class B network, the network address is the
first two bytes of the IP address. For a class C
network, the network address is the first three
bytes of the IP address. In each case, the
remainder is the host address. In the Internet,
assigned network addresses are globally
unique. See
IP address.
node An addressable device attached to a
computer network. See
host, router.
P
packet The unit of data sent across a network.
“Packet” is a generic term used to describe
units of data at all levels of the protocol stack,
but it is most correctly used to describe
application data units. See
datagram, frame.
policy Organization-level rules governing
acceptable use of computing resources,
security practices, and operational procedures.
POP3: POP3 (Post Office Protocol 3) is the
most recent version of a standard protocol for
receiving e-mail. POP3 is a client/server
protocol in which e-mail is received and held
for you by your Internet server. Periodically,
you (or your client e-mail receiver) check your
mail-box on the server and download any mail.
POP3 is built into the Netmanage suite of
Internet products and one of the most popular
e-mail products, Eudora. It's also built into the
Netscape and Microsoft Internet Explorer
browsers.
PPP: PPP (Point-to-Point Protocol) is a
protocol for communication between two
computers using a serial interface, typically a
personal computer connected by phone line to
a server. PPP uses the Internet protocol (IP)
(and is designed to handle others). It is
sometimes considered a member of the
TCP/IP suite of protocols. Relative to the Open
Systems Interconnection (OSI) reference
model, PPP provides layer 2 (data-link layer)
service. Essentially, it packages your
computer's TCP/IP packets and forwards them
to the server where they can actually be put on
the Internet.
PPP is a full-duplex protocol that can be used
on various physical media, including twisted
pair or fiber optic lines or satellite
transmission. It uses a variation of High Speed
Data Link Control (HDLC) for packet
encapsulation.
PPP is usually preferred over the earlier de
facto standard Serial Line Internet Protocol
(SLIP) because it can handle synchronous as
well as asynchronous communication. PPP
can share a line with other users and it has
error detection that SLIP lacks. Where a
choice is possible, PPP is preferred.
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