Ericsson MINI-LINK BAS, Technical Description, Page: 113 / 174

6-29 MINI-LINK BAS
EN/LZB 111 0542 P2B Technical Description
6.11 Internal Communication
This section describes the communication structure used for the
management of the MINI-LINK BAS. Several communication levels
exist in the system to each of them is dedicated a separate subsection.
6.11.1 Communication between EM and CP
The communication between EM and CP is done using a proprietary
protocol over TCP/IP. A normal Ethernet connection is provided
between EM and CP.
The protocol is based upon a manager-agent approach, where the
manager asks the agent about specific information items. It is the
responsibility of the agent to find such an information and to present it
to the manager. In our case, the EM makes the role of the manager and
the CP represents the agent.
The protocol requires the manager and the agent to share the
information structure of the objects they want to handle; this is called
Managed Information Base (MIB).
6.11.2 Communication between CP and DP
The communication between CP and DPs is controlled by the ICS.
The ICS provides facilities for link supervision, message
acknowledgement, message retransmission, Erlang interface, and so
on.
The ICS protocol between CP and DPs is ICS over ATM (ICS/ATM),
as shown in Figure 6-10. The ICS messages are mapped into ATM
cells by using the AAL5.
Internal Communication System
AAL5
ATM
Physical layer
ICS/ATM
Figure 6-10 ICS over ATM.