Reference Manual

Function Change
DMRU Distributed Main Replaceble Unit. A
Main RU is said to be distributed if it is
subordinated to the CMRU.
Main RU Contains one or more processors, to which
software can be downloaded from the
BSC. A Main RU is either central or
distributed, see above. A Main RU may
or may not have a direct signalling link to
the BSC.
RU Replaceble Unit. An RU is the smallest
unit that can be handled on site or in a
repair center and of which information can
be retrieved via OMT or BSC.
Sub-RU A Sub-RU is always connected to a
superior Main RU. This connection is
used for retrieval of equipment
information. A Sub-RU normally does not
have a processor. Note that an RU with a
processor that is not loadable, is classified
as a Sub-RU. In the RBS 2000 hardware
architecture, for example the CDUs are
Sub-RUs.
36.2 Functions
RBS
SW file
01_0285A
Distributed
main RU
Central
main RU
File
package
A-bis
Figure 101 Overview of function change
36.2.1 Software Storage
Every Main RU is equipped with both volatile and non-volatile memory.
Application software, either downloaded via the A-bis interface,
transferred internally, or installed during manufacture, is stored
semi-permanently in the non-volatile memory.
Before execution, the software is copied from the non-volatile memory
into the volatile memory, where it is executed. This arrangement permits
the RBS to operate normally, that is, executing one version of software
while loading a new version of software as a background activity.
One area of the non-volatile memory contains the base application
software. The base application software can only be updated by
274 (421)
EN/LZT 720 0008 R1A
2001-06-26
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