TMS zl Management and Configuration Guide ST.1.0.090213
B-2
Glossary
AF Assured Forwarding. A Differentiated Services PBH group comprised of four
classes that allows a provider DS domain to offer different levels of forwarding
assurances for IP packets received from a customer DS domain.
aggressive mode Aggressive mode uses three total messages during IKE phase 1—two from the
initiator and one from the responder.
AH Authentication Header. A part of the IPsec protocol suite that guarantees
connectionless integrity and data origin authentication of IP packets. For more
information, see RFC 4302 at http://www.ietf.org/rfc/rfc4302.txt. Also see ESP.
ALG Application-Layer Gateway. An application-level gateway acts as a proxy
server between a trusted client and an untrusted host, and accepts only
packets generated by services it is designed to copy, forward, and filter.
anomaly Deviation from a set standard. For example, a traffic anomaly is a deviation
from normal traffic behavior.
anomaly-based
IPS
IPS that looks for irregularities. Different types of anomaly-based IPSs look for
irregularities in different places, such as traffic flow, protocol headers, or
protocol payloads.
anti-replay
window
The TMS zl Module drops out-of-order packets to protect against replay
attacks. However, because packets might arrive slightly out of order, the TMS
zl Module accepts packets that arrive within the anti-replay window.
application
inactive timeout
A timeout applied to an application.
application-level
gateway
See ALG.
apply An action for an IPsec policy. Apply means that the policy affects all traffic that
is specified in the traffic selector. See also Ignore and Bypass.
area border router See ABR.
ARP Address Resolution Protocol. A protocol that is used to map MAC addresses
to IP addresses. For more information, see RFC 2390 at http://www.ietf.org/
rfc/rfc2390.txt.
AS Autonomous System. The network or collection of networks under the same
administrative control.
ASBR Autonomous System Border Router. A router that connects to an external
network and runs both OSPF and the external network’s routing protocol.
ASBR routers are within the OSPF backbone area (Area 0).