SSH EN 300 175-4 V2.6.1:2015

Digital Enhanced Cordless Telecommunications (DECT); Common Interface (CI); Part 4: Data Link Control (DLC) layer

Scope

The present document is one of the parts of the specification of the Digital Enhanced Cordless Telecommunications
(DECT) Common Interface (CI).
The present document specifies the Data Link Control (DLC) layer. The DLC layer is part 4 of the DECT CI standard
and layer 2b of the DECT protocol stack.
Network layer Network layer
C-plane (3) U-plane
DLC layer DLC layer
C-plane (2b) U-plane
MAC layer
(2a)
Physical layer
(1)
Figure 1.1
Two planes of operation are specified for this DLC (sub)layer. These planes are called the Control plane (C-plane) and
the User plane (U-plane).
The C-plane is mostly concerned with the DECT signalling aspects. It provides a reliable point-to-point service that
uses a link access protocol to offer error protected transmission of Network (NWK) layer messages. The C-plane also
provides a separate point-to-multipoint (broadcast) service (Lb).
The U-plane is only concerned with end-to-end user information. This plane contains most of the application dependent
procedures of DECT. Several alternative services (both circuit-mode and packet-mode) are defined as a family of
independent entities. Each service provides one or more point-to-point U-plane data links, where the detailed
characteristics of those links are determined by the particular needs of each service. The defined services cover a wide
range of performance, from "unprotected with low delay" for speech applications to "highly protected with variable
delay", for local area network applications.
NOTE: The performance of the DLC services need not be tight to any particular application. For example the
"unprotected with low delay" service could also be used for data applications, e.g. if some data protection
is provided outside the DECT protocol.
The present document uses the layered model principles and terminology as described in Recommendations ITU-T
X.200 [14] and X.210 [15].
The present document includes New Generation DECT, a further development of the DECT standard introducing
wideband speech, improved data services, new slot types and other technical enhancements.