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Asus SL1000 User Manual

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Appendix 16. Glossary

Internet Security Router User

’s Manual

146

between your ISP and your computer. The WAN interface on the Internet Security
Router uses two forms of PPP called PPPoA and PPPoE. See also PPPoA, PPPoE.

PPPoE

Point-to-Point Protocol over Ethernet

One of the two types of PPP interfaces you can define for a Virtual Circuit (VC), the
other type being PPPoA. You can define one or more PPPoE interfaces per VC.

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.

remote

In a physically separate location. For example, an employee away on travel who logs in

to the company

’s intranet is a remote user.

RIP

Routing Information Protocol

The original TCP/IP routing protocol. There are two versions of RIP: version I and
version II.

RJ-45

Registered Jack Standard-45

The 8-pin plug used in transmitting data over phone lines. Ethernet cabling usually
uses this type of connector.

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.

rule

See filtering rule, NAT rule.

SDNS

Secondary Domain Name System (server)

A DNS server that can be used if the primary DSN server is not available. See DNS.

SNMP

Simple Network Management Protocol

The TCP/IP protocol used for network management.

subnet

A subnet is a portion of a network. The subnet is distinguished from the larger network

by a subnet mask which 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. See
also network mask
.

subnet mask

A mask that defines a subnet. See also network mask.

TCP

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 (the web protocol) 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.

TFTP

Trivial File Transfer Protocol

A protocol for file transfers, TFTP is easier to use than File Transfer Protocol (FTP) but
not as capable or secure.

TTL

Time To Live

A field in an IP packet that limits the life span of that packet. Originally meant as a time
duration, the TTL is usually represented instead as a maximum hop count; each router
that receives a packet decrements this field by one. When the TTL reaches zero, the
packet is discarded.