Asus Internet Security Router User Manual page 162

Appendix 16. Glossary
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.
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Internet Security Router User's Manual