Glossary
GL-2
Cisco Router and Security Device Manager Version 2.2 User’s Guide
OL-4015-08
address translation The translation of a network address and/or port to another ne twork address/or
port. See also IP address, NAT, PAT, Static PAT.
ADSL asymmetric digital subscriber line.
aggressive mode A mode of establishing ISAKMP SAs that simplifies IKE authentication
negotiation (phase 1) between two or more IPSec peers. Aggressive mode is
faster than main mode, but is not as secure. See main mode, quick mode.
AH Authentication Header. This is an older IPSec protocol that is less important in
most networks than ESP. AH provides authentication services but does not
provide encryption services. It is provided to ensure compatibility with IPSec
peers that do not support ESP, which provides both authentication and
encryption.
AH-MD5-HMAC Authentication Header with the MD5 (HMAC variant) hash algorithm.
AH-SHA-HMAC Authentication Header with the SHA (HMAC variant) hash algorithm.
AHP Authentication Header Protocol. A protocol that provides source host
authentication, and data integrity. AHP does not provide secrecy.
algorithm A logical sequence of steps for solving a problem. Security algorithms pertain
to either data encryption or authentication.
DES and 3DES are two examples of data encryption algorithms.
Examples of encryption-decryption algorithms include block cipher, CBC, null
cipher, and stream cipher.
Authentication algorithms include hashes such as MD5 and SHA.
AMI alternate mark inversion.
ARP Address Resolution Protocol—A low-level TCP/IP protocol that maps a node
hardware address (called a MAC address) to its IP address.
ASA Adaptive Security Algorithm. Allows one-way (inside to outside) connections
without an explicit configuration for each internal system and application.