CTC Store CTS Union IP DSLAM for ADSL IPDSLAM-A8/A16 - Manual (Page 134)

VIII
Glossary
AAL
ATM adaptation layer. Service-dependent sublayer of the data link layer. The AAL
accepts data from different applications and presents it to the ATM layer in the
form of 48-byte ATM payload segments. AALs consist of two sublayers: CS and
SAR. AALs differ on the basis of the source-destination timing used (CBR or VBR)
and whether they are used for connection-oriented or connectionless mode data
transfer. At present, the four types of AAL recommended by the ITU-T are AAL1,
AAL2, AAL3/4, and AAL5.
AAL5
ATM adaptation layer 5. One of four AALs recommended by the ITU-T. AAL5
supports connection-oriented VBR services and is used predominantly for the
transfer of classical IP over ATM and LANE traffic. AAL5 uses SEAL and is the
least complex of the current AAL recommendations. It offers low bandwidth
overhead and simpler processing requirements in exchange for reduced
bandwidth capacity and error-recovery capability. See also AAL.
ADSL
Asymmetric digital subscriber line. ADSL is designed to deliver more bandwidth
downstream (from the central office to the customer site) than upstream.
Downstream rates range from 1.5 to 9 Mbps; upstream bandwidth ranges from 16
kbps to 1 Mbps. ADSL transmissions work at distances up to 18,000 feet over a
single copper wire twisted pair. See also DSL.
Agent
Generally, software that processes queries and returns replies on behalf of an
application. In the context of network management, an agent is a process that
resides in all managed devices, and stores management data and responds to the
manager’s data requests.
ATM
Asynchronous Transfer Mode. A cell-based data transfer technique in which
channel demand determines packet allocation. ATM offers fast packet technology,
real times; demand led switching for efficient use of network resources. This is an
International standard for cell relay in which multiple service types (such as voice,
video or data) are conveyed in fixed-length (53-byte) cells. Fixed-length cells allow
cell processing to occur in hardware, thereby reducing transit delays. ATM is
designed to take advantage of high-speed transmission media such as E3,
SONET, and T3.