User guide

Glossary
70 1553-ZAT 759 94 Uen A – October 2004
WAN interface on the HM410dp uses a form
of PPP called PPPoE (PPP over Ethernet).
Protocol
A set of rules governing the transmission of
data. In order for a data transmission to work,
both ends of the connection have to follow the
rules of the protocol.
Routing
Forwarding data between your network and
the Internet on the most efficient route, based
on the data’s destination IP address and
current network conditions. A device that
performs routing is called a router.
Subnet
A subnet is a portion of a network. The
subnet is distinguished from the larger
network by a subnet mask that selects some
of the computers of the network and excludes
all others. The subnet’s computers remain
physically connected to the rest of the parent
network, but they are treated as though they
were on a separate network.
Subnet mask
A mask that defines a subnet. See also
Network mask.
TCP – Transmission Control Protocol
See TCP/IP.
TCP/IP – Transmission Control Protocol /
Internet Protocol
The basic protocols used on the Internet.
TCP is responsible for dividing data up into
packets for delivery and reassembling them
at the destination, while IP is responsible for
delivering the packets from source to
destination. When TCP and IP are bundled
with higher-level applications such as HTTP,
FTP, Telnet, etc., TCP/IP refers to this whole
suite of protocols.
Telnet
An interactive, character-based program used
to access a remote computer. While HTTP
and FTP only allow you to download files
from a remote computer, Telnet allows you to
log into and use a computer from a remote
location.
Triggers
Triggers are used to deal with application
protocols that create separate sessions.
Some applications, such as NetMeeting, open
secondary connections during normal
operations, for example, a connection to a
server is established using one port, but data
transfers are performed on a separate
connection. A trigger tells the device to
expect these secondary sessions and how to
handle them.
UDP – User Datagram Protocol
A connectionless transport service that
dispenses with the reliability services
provided by the TCP. UDP gives applications
a direct interface with IP and the ability to
address a particular application process
running on a host via a port number, without
setting up a connection session.
UPnP – Universal Plug and Play
A networking architecture that provides
compatibility among networking equipment.
UPnP boasts device-driver independence and
zero-configuration networking.
Upstream
The direction of data transmission from the
user to the Internet.
Virtual Server
A server, usually a Web server, that shares
computer resources with other virtual servers.
In this context, the virtual part simply means
that it is not a dedicated server – that is, the
entire computer is not dedicated to running
the server software. Instead of requiring a
separate computer for each server, dozens of
virtual servers can co-reside on the same
computer.