User's Manual

T-311 11Mb High Gain Smart Ethernet Client User’s Guide
Gemtek Systems Page 33
related services such as Web site building and
virtual hosting. An ISP has the equipment and
the telecommunication line access required to
have a point-of-presence on the Internet for the
geographic area served.
L
LAN: A local area network (LAN) is a group of
computers and associated devices that share a
common communications line and typically
share the resources of a single processor or
server within a small geographic area (for
example, within an office building). Usually, the
server has applications and data storage that
are shared in common by multiple computer
users. A local area network may serve as few
as two or three users (for example, in a home
network) or many as thousands of users (for
example, in an FDDI network).
M
MAC: Medium Access Control. In a WLAN
network card, the MAC is the radio controller
protocol. It corresponds to the ISO Network
Model's level 2 Data Link layer. The IEEE
802.11 standard specifies the MAC protocol for
medium sharing, packet formatting and
addressing, and error detection.
N
NAT: NAT (Network Address Translation) is the
translation of an Internet Protocol address (IP
address) used within one network to a different
IP address known within another network. One
network is designated the inside network and
the other is the outside. Typically, a company
maps its local inside network addresses to one
or more global outside IP addresses and
unmaps the global IP addresses on incoming
packets back into local IP addresses.
NAT is included as part of a router and is often
part of a corporate firewall.
P
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.
PPPoE: PPPoE (Point-to-Point Protocol over
Ethernet) is a specification for connecting
multiple computer users on an Ethernet local
area network to a remote site through common
customer premises equipment, which is the
telephone company's term for a modem and
similar devices. PPPoE can be used to have
an office or building-full of users share a
common Digital Subscriber Line (DSL), cable
modem, or wireless connection to the Internet.
PPPoE combines the Point-to-Point Protocol
(PPP), commonly used in dialup connections,
with the Ethernet protocol, which supports
multiple users in a local area network. The
PPP protocol information is encapsulated
within an Ethernet frame.
PPPoE has the advantage that neither the
telephone company nor the Internet service
provider (ISP) needs to provide any special
support. Unlike dialup connections, DSL and
cable modem connections are "always on."
Since a number of different users are sharing
the same physical connection to the remote
service provider, a way is needed to keep track
of which user traffic should go to and which