This soft copy for use by IBM employees only.
GlossaryAAAL (ATM Adaptation Layer). The layer that
adapts user data to/from the ATM network by
adding/removing headers and
segmenting/reassembling the data into/from cells.
AAL-5 (ATM adaptation Layer 5). One of several
standard AALs, AAL-5 was designed for data
communications and is used by LAN Emulation and
classical IP.
ABR (Available Bit Rate). ATM Forum Service
category in relation to traffic Management on ATM
networks. Use bandwidth available in the running
network after other traffic utilizing guaranteed
bandwidth services has been serviced.
ARP (Address Resolution Protocol). IP ARP
translate network addresses into hardware addresses,
LE ARP translates LAN destinations into ATM
addresses.
asynchronous. Any two events that are not tied
together exactly in time are said to be asynchronous.
ATM (asynchronous transfer mode). A transfer
mode in which the information is organized into cells.
It is asynchronous in the sense that the recurrence of
cells containing information from an individual user is
not necessarily periodic.
ATM layer. The layer in the protocol model which
relays cells from one connection to another.
ATM peer-to-peer connection. A virtual channel
connection (VCC) or a virtual path connection (VPC).
ATM user-to-user connection. An association
established at the ATM layer to support
communication between two or more ATM service
users (that is, between two or more next higher layer
entities or between two or more ATM entities). The
communication over an ATM layer connection may be
either bidirectional or unidirectional. The same
virtual channel identifier (VCI) is used for both
directions of a connection at an interface.
ATM layer link. A section of an ATM layer connection
between two active ATM layer entities (ATM entities).
ATM link. A virtual path link (VPL) or a virtual
channel link (VCL).
BBroadcast. A value of the service attribute
“communication configuration”, which denotes
unidirectional distribution to all users.
BCM (Broadcast Manager). An IBM extension to
LAN Emulation designed to limit the effects of
broadcast frames
BUS (Broadcast and Unknown Server). A LAN
emulation Service component responsible for the
delivery of multicast and unknown unicast frames.
Ccell header. ATM layer protocol control information.
CBR (Constant Bit Rate). ATM Forum Service
category in relation to traffic Management on ATM
networks. Includes anything where a continuous
stream of bits at a predefined constant rate is
transported through the network.
cell loss priority. A control descriptor in each ATM
cell header which indicates the relative importance of
the cell. If set to zero it should not be discarded, if
set to one it may be discarded.
CIP (Classical IP). An IETF standard for
ATM-attached devices to communicate using IP.
CIPC (Classical IP Client). A classical IP component
that represents users of the classical IP Subnet.
CAC (connection admission control). The set of
actions taken by the network at the call setup phase
(or during call re-negotiation phase) in order to
establish whether a virtual channel/virtual path
connection can be accepted or rejected (or a request
for re-allocation can be accommodated). Routing is
part of connection admission control actions.
congestion control. The set of actions taken to
relieve congestion by limiting its spread and duration.
connection oriented. Communication where there is
a connection provided between sender and receiver,
which must be maintained for data to be transferred.
connectionless service. A service which allows the
transfer of information between service users without
the need for end-to-end call establishment
procedures.
constant bit rate service. A type of
telecommunication service characterized by a service
bit rate specified by a constant value.
Copyright IBM Corp. 1996 285