ZyXEL Communications Prestige 643 User Manual page 180

Prestige 643 ADSL Router
Port
POTS
PPP
PSTN
PTT
PVC
RADIUS
Accounting
RADIUS
Authentication
RFC
V
An Internet port refers to a number that is part of a URL, appearing after a colon (:)
right after the domain name. Every service on an Internet server listens on a
particular port number on that server. Most services have standard port numbers, e.g.
Web servers normally listen on port 80.
Plain Old Telephone Service is the analog telephone service that runs over copper
twisted-pair wires and is based on the original Bell telephone system. Twisted-pair
wires connect homes and businesses to a neighborhood central office. This is called
the local loop. The central office is connected to other central offices and long-
distance facilities.
Point to Point Protocol. PPP encapsulates and transmits IP (Internet Protocol)
datagrams over serial point-to-point links. PPP works with other protocols such as
IPX (Internetwork Packet Exchange). The protocol is defined in IETF (Internet
Engineering Task Force) RFC 1661 through 1663. PPP provides router-to-router,
host-to-router and host-to-host connections.
Public Switched Telephone Network was put into place many years ago as a voice
telephone call-switching system. The system transmits voice calls as analog signals
across copper twisted cables from homes and businesses to neighborhood COs
(central offices); this is often called the local loop. The PSTN is a circuit-switched
system, meaning that an end-to-end private circuit is established between caller and
callee.
The generic European name is usually used to refer to state-owned telephone
companies.
Permanent Virtual Circuit. A PVC is a logical point-to-point circuit between
customer sites. PVCs are low-delay circuits because routing decisions do not need to
be made along the way. Permanent means that the circuit is preprogrammed by the
carrier as a path through the network. It does not need to be set up or torn down for
each session.
This facility logs information about dial-in connections. It can be used independently
of RADIUS Authentication. It allows data to be sent at the start and the end of
sessions, indicating the amount of resources (time, packets, bytes, etc.) used during
the session. An ISP could use this function for special security and billing needs.
An external RADIUS server can provide authentication service for an unlimited
number of DSL users.
An RFC (Request for Comments) is an Internet formal document or standard that is
the result of committee drafting and subsequent review by interested parties. Some
RFCs are informational in nature. Of those that are intended to become Internet
Glossary