Enterasys ANG-1100 User Manual page 57

Appendix A
Glossary
Generic Routing Encapsulation (GRE)
Tunneling protocol developed by Cisco that can encapsulate a wide variety of
protocol packet types inside IP tunnels, creating a virtual point-to-point link
over the Internet. For PPTP, GRE is used to encapsulate PPP data packets
within an IP packet (IP packet headers contain address information necessary
for routing, while PPP packets do not).
Internet Service Provider (ISP)
A vendor who provides direct access to the Internet. ISPs bill users for the
amount of time they are connected, and may also offer additional services
such as Web site hosting, E-mail, or news group readers. Remote users reach
the ISP by dialing into an ISP POP with a computer, modem, and phone line,
or over a dedicated circuit (such as a cable modem connection).
IP
Abbreviation of Internet Protocol, pronounced as two separate letters. IP
specifies the format of packets, also called datagrams, and the addressing
scheme. Most networks combine IP with a higher-level protocol called
Transport Control Protocol (TCP/IP), which establishes a virtual connection
between a destination and a source.
IP Address
An identifier for a computer or device on a TCP/IP network. Networks using
the TCP/IP protocol route messages based on the IP address of the
destination. The format of an IP address is a 32-bit numeric address written as
four numbers separated by periods. Each number can be zero to 255. For
example, 172.16.4.14 could be an IP address.
IP Security Protocol (IPSec)
Short for IPSecurity, a set of protocols developed to support secure exchange
of packets at the IP layer.
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