User's Manual

Prestige 645 ADSL Internet Access Router
Glossary G
PAP Password Authentication Protocol PAP is a security protocol that requires users to enter a
password before accessing a secure system. The user’s name and password are sent over the
wire to a server, where they are compared with a database of user account names and
passwords. This technique is vulnerable to wiretapping (eavesdropping) because the
password can be captured and used by someone to log onto the system.
Port 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.
POTS 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.
PPP 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.
PPPoE PPPoE (Point-to-Point Protocol over Ethernet) relies on two widely accepted standards: PPP
and Ethernet. PPPoE is a specification for connecting the users on an Ethernet to the Internet
through a common broadband medium, such as a single DSL line, wireless device or cable
modem. All the users over the Ethernet share a common connection, so the Ethernet
principles supporting multiple users in a LAN combine with the principles of PPP, which
apply to serial connections. From authentication, accounting and secure access to
configuration management, PPPoE supports a broad range of existing applications and
services.
PSTN 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.
PVC 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.
RFC 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