3Com 7000 Switch User Manual


 
132
G
LOSSARY
connection-
oriented
communications
A form of packet-switching that requires a predefined circuit from
source to destination to be established before data can be transferred.
crankback
A mechanism used by ATM networks when a connection setup request
is blocked. The path is rolled back to an intermediate node, which
attempts to discover another path to the final destination.
CTD
Cell Transfer Delay. This is defined as the elapsed time between a cell
exit event at measurement point 1 (e.g., at the source UNI) and the
corresponding cell entry event at measurement point 2 (e.g.,the
destination UNI) for a particular connection. The cell transfer delay
between two points is the sum of the total inter-ATM node
transmission delay and the total ATM node processing delay.
D
database
synchronization
PTSE information is flooded on a continuous basis, until each node in
the peer group has the same information in its database.
DCE
Data Communications Equipment.
The equipment providing functions
that establish, maintain and terminate a data transmission connection.
DTE
Data Terminal Equipment. The equipment connected to the common
carrier communications facility. The DTE is typically a computer system
or terminal.
DTL
Designated Transit List. A list of node and optionally link IDs that
completely specify a path across a single PNNI peer group.
E
E.164
A public network addressing standard utilizing up to a maximum of 15
digits. ATM uses E.164 addressing for public network addressing.
end system / end
station
A system where an ATM connection is terminated or initiated. An
originating end system initiates the ATM connection, and a terminating
end system terminates the ATM connection. OAM cells may be
generated and received.
EFCI
Explicit Forward Congestion Indication. EFCI is a congestion notification
mechanism that the ATM layer service user may make use of to
improve the utility that can be derived from the ATM layer. The ABR