ZyXEL Communications Prestige 642R Series User Manual page 154

Prestige 642R Series ADSL Router
connections.
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
informational in nature. Of those that are intended to become Internet standards, the final
version of the RFC becomes the standard and no further comments or changes are
permitted. Change can occur, however, through subsequent RFCs.
RIP Routing Information Protocol is an interior or intra-domain routing protocol that uses the
distance-vector routing algorithms. RIP is used on the Internet and is common in the NetWare
environment as a method for exchanging routing information between routers.
SAP In NetWare, the SAP (Service Advertising Protocol) broadcasts information about available
services on the network that other network devices can listen to. A server sends out SAP
messages every 60 seconds. A server also sends out SAP messages to inform other devices
that it is closing down. Workstations use SAP to find services they need on the network.
Server A computer, or a software package, that provides a specific kind of service to client software
running on other computers.
SNMP System Network Management Protocol is a popular management protocol defined by the
Internet community for TCP/IP networks. It is a communication protocol for collecting
information from devices on the network.
STP
Twisted-pair cable consists of copper-core wires surrounded by an insulator. Two wires are
twisted together to form a pair, and the pair form a balanced circuit. The twisting prevents
interference problems. STP (shielded twisted-pair) provides protection against external
crosstalk.
Straight A cable that wires a pin to its equivalent pin. This cable connects two dissimilar devices, for
Through
example, a data terminal equipment (DTE) and a data communications equipment (DCE)
Ethernet device. A straight through Ethernet cable is the most common cable used.
Cable
SUA
Single User Account. The Prestige's SUA (Single User Account) feature allows multiple user
Internet access for the cost of a single ISP account - see also NAT.
TCP Transmission Control Protocol handles flow control and packet recovery and IP providing
basic addressing and packet-forwarding services.
Telnet
Telnet is the login and terminal emulation protocol common on the Internet and in UNIX
environments. It operates over TCP/IP networks. Its primary function is to allow users to log
into remote host systems.
Terminal
A device that allows you to send commands to a computer somewhere else. At a minimum,
this usually means a keyboard and a display screen and some simple circuitry.
Terminal
Software that pretends to be (emulates) a physical terminal and allows you to type commands
Software
to a computer somewhere else.
TFTP Trivial File Transfer Protocol is an Internet file transfer protocol similar to FTP (File Transfer
D Glossary