User's Manual Part 2

User’s Guide Glossary
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.
S
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 user should be billed. PPPoE provides
for each user-remote site session to learn
each other's network addresses (during an
initial exchange called "discovery"). Once a
session is established between an individual
user and the remote site (for example, an
Internet service provider), the session can be
monitored for billing purposes.
PPTP: Point-to-Point Tunneling Protocol
(PPTP) is a protocol (set of communication
rules) that allows corporations to extend their
own corporate network through private
"tunnels" over the public Internet. Effectively, a
corporation uses a wide-area network as a
single large local area network. This kind of
interconnection is known as a virtual private
network (VPN).
R
RADIUS: RADIUS (Remote Authentication Dial-
In User Service) is a client/server protocol and
software that enables remote access servers
to communicate with a central server to
authenticate dial-in users and authorize their
access to the requested system or service.
RADIUS allows a company to maintain user
profiles in a central database that all remote
servers can share. It provides better security,
allowing a company to set up a policy that can
be applied at a single administered network
point. Having a central service also means that
it's easier to track usage for billing and for
keeping network statistics.
SNMP: Simple Network Management Protocol
(SNMP) is the protocol governing network
management and the monitoring of network
devices and their functions. It is not
necessarily limited to TCP/IP networks.
SNMP is described formally in the Internet
Engineering Task Force (IETF) Request for
Comment (RFC) 1157 and in a number of
other related RFCs.
SSL: The Secure Sockets Layer (SSL) is a
commonly-used protocol for managing the
security of a message transmission on the
Internet. SSL has recently been succeeded by
Transport Layer Security (TLS), which is
based on SSL. SSL uses a program layer
located between the Internet's Hypertext
Transfer Protocol (HTTP) and Transport
Control Protocol (TCP) layers. The "sockets"
part of the term refers to the sockets method
of passing data back and forth between a
client and a server program in a network or
between program layers in the same
computer. SSL uses the public-and-private key
encryption system from RSA, which also
includes the use of a digital certificate.
T
TCP: TCP (Transmission Control Protocol) is a
set of rules (protocol) used along with the
Internet Protocol (IP) to send data in the form
of message units between computers over the
Internet. While IP takes care of handling the
actual delivery of the data, TCP takes care of
keeping track of the individual units of data
(called packets) that a message is divided into
for efficient routing through the Internet.
TCP is a connection-oriented protocol, which
means that a connection is established and
maintained until such time as the message or
messages to be exchanged by the application
programs at each end have been exchanged.
TCP is responsible for ensuring that a
message is divided into the packets that IP
manages and for reassembling the packets
back into the complete message at the other
end. In the Open Systems Interconnection
(OSI) communication model, TCP is in layer 4,
the Transport Layer.
Gemtek Systems Page 148