ZyXEL Communications Prestige 964 User Manual page 49

Port (H/W) An interface on a computer for connecting peripherals or devices to the computer. A printer port,
for example, is an interface that is designed to have a printer connected to it. Ports can be defined
by specific hardware (such as a keyboard port) or through software.
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.
PPTP Point-to-Point Tunneling Protocol.
Promiscuous Packet Actively capturing packet information from a network. Most computers only collect packets
Capture specifically addressed to them. Promiscuous packet capture acquires all network traffic it can
regardless of where the packets are addressed.
Protocol A "language" for communicating on a network. Protocols are sets of standards or rules used to
define, format, and transmit data across a network. There are many different protocols used on
networks. For example, most web pages are transmitted using the HTTP protocol.
Proxy Server A server that performs network operations in lieu of other systems on the network. Proxy Servers
are most often used as part of a firewall to mask the identity of users inside a corporate network
yet still provide access to the Internet. When a user connects to a proxy server, via a web browser
or other networked application, he submits commands to the proxy server. The server then
submits those same commands to the Internet, yet without revealing any information about the
system that originally requested the information. Proxy servers are an ideal way to also have all
users on a corporate network channel through one point for all external communications. Proxy
servers can be configured to block certain kinds of connections and stop some hacks.
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.
Public Key System of encrypting electronic files using a key pair. The key pair contains a public key used
Encryption during encryption, and a corresponding private key used during decryption.
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.
The process of automatically adjusting transmission levels and time offsets of individual modems
Ranging
in order to make sure the bursts coming from different modems line up in the right timeslots and
are received at the same power level at the CMTS.
Reconnaissance The finding and observation of potential targets for a cracker to attack.
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 informational in
nature. Of those that are intended to become Internet standards, the final version of the RFC
Glossary
Prestige 964 Cable Router
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