Principles of Operation
4-33610-A2-GB41-60 March 1999
Multipoint Transmission
In multipoint transmission (Figure 4-1), a control DSU
is connected through the digital facility to multiple
tributaries communicating at the same rate. Traditionally,
a tributary site (often referred to as a drop) can transmit
data only when it is polled by the front-end processor
(FEP). The FEP, a communications computer associated
with a host computer, is the data terminal equipment
(DTE) at the control DSU.
A 3600 Series DSU can be configured as a control or
as a tributary in multipoint transmission. A control 3610
or 3611 DSU provides diagnostic support for up to
40 addressable tributary devices using MCMP, multipoint
nondisruptive, or mixed diagnostics. Without diagnostics
and poll list, 254 addressable devices are supported.
A circuit employing multipoint transmission is referred
to as a multipoint circuit.
Figure 4-1. Multipoint Transmission