User Manual Part 3

User’s Guide Version 1.0
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).
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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.
S
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.
TCP/IP: TCP/IP (Transmission Control
Protocol/Internet Protocol) is the basic
communication language or protocol of the
Internet. It can also be used as a
communications protocol in a private network
(either an intranet or an extranet). When you
are set up with direct access to the Internet,
your computer is provided with a copy of the
TCP/IP program just as every other computer
that you may send messages to or get
information from also has a copy of TCP/IP.