HP ProCurve Secure 7000dl Series Basic Management And Configuration Manual page 730

Appendix B: Glossary
AH Authentication Header. One of the IPSec protocols that can encapsulate
ALG Application Level Gateway. A protocol that acts as a proxy server between a
AMI Alternate Mark Inversion. A line-coding scheme used with T1 and E1 connec-
Analog A continuously varying electrical sinusoidal signal. This signal type is used for
ANI Automatic Number Identification. A service that provides the receiver of a
ANSI American National Standards Institute. An organization that fosters the devel-
AO/DI Always On/Dynamic ISDN. A form of ISDN connection that allows the BRI D
Application Layer Layer 7 of the OSI model. This layer supports application services for file
ARCFour A symmetric encryption algorithm supported by IP Security (IPSec), the
ARM Asynchronous Response Mode. ARM designates a type of High-Level Data-
ARP Address Resolution Protocol. A Network Layer Ethernet protocol used to
B-4
packets sent over a VPN tunnel. AH uses authentication algorithms to ensure
the integrity of the packet contents. AH authenticates the entire IPSec packet,
including the delivery IP header. See also IPSec.
trusted client behind a firewall and an untrusted client. ALGs analyze and filter
packets at the OSI Application Layer and provide applications the special
services that they need to function through a firewall. Each application must
have its own ALG.
tions. Logical zeros are transmitted as zero voltage, and logical ones are
transmitted as pulses with alternating polarity.
voice or data transmission.
telephone call with the number of the calling phone. Also known as Caller ID.
opment of technology standards in the United States. For more information
on ANSI, visit the ANSI Web site at http://www.ansi.org/.
channel to be used for a low-speed data connection. Because the D channel
is always active, this connection is considered always on.
transfers, e-mail, and other network software services. Telnet and FTP are
applications that work at the Application Layer.
industry standard for virtual private networks (VPNs). ARCFour is a stream
cipher that supports keys ranging from 8 to 2048 bits in length.
Link Control (HDLC) connection between a primary and secondary device,
during which the secondary device can initiate a transmission, but the primary
device controls the establishment and termination of the link. See also HDLC.
convert a network IP address into a physical address. A host that wants to
obtain a physical address broadcasts an ARP request onto the TCP/IP network.