Showing posts with label BSS. Show all posts
Showing posts with label BSS. Show all posts

Nokia BSC with MML commands:



ZAHP PRINT ALARM HISTORY
ZAHO PRINT ALARMS CURRENTLY ON
ZIGO DISPLAY MML COMMAND LOG
ZWQO SHOW SOFTWARE PACKAGE INFORMATION
ZW7I INTERROGATE LICENCE OR FEATURE INFORMATION
ZEFR RESET SITE/BCF
ZEQS LOCK UNLOCK BTS
ZERS LOCK UNLOCK TRX
ZEQM MODIFY BTS PARAMETERS
ZEAO OUTPUT GSM ADJACENT
ZEUO OUTPUT POWER CONTROL PARAMETERS
ZEHO OUTPUT HANDOVER PARAMETERS

LAPD protocol

All messages sent on the A-bis interface use the LAPD protocol that enables reliable transmission of information. LAPD provides two kinds of transfer modes: Unacknowledged info transfer with no guarantee that the information frame is successfully delivered to the addressee, and acknowledged information transfer, where each signal is acknowledged, and the system makes sure that the frame has reached the destination successfully. Only measurement reports use unacknowledged information transfer.
Frame Structure and Data Links
A flag, 01111110 (h'7E), delimits a frame. The one flag is enough between consecutive frames. The receiving entity looks for the flag 01111110 to synchronize on the start of a frame.

TEI and SAPI are used to access the right entity and right function at the receiving end.
SAPI
is the address used to access different functions, such as TRXC, CF and Layer 2 management procedures, within one physical entity. The CF (Central Function) link is used in RBS 2000 for common management functions for the TG, for example BTS software download.



TEI
is the address used to access different physical entities such as an individual TRX for radio signaling.

Two data link types are defined for each TEI. The data link types and their corresponding SAPI are:
SAPI=0
is used for the Radio Signaling Link (RSL). This link is used for supporting traffic management procedures mainly for circuit switched traffic. Signalling on Packet Data Channels (PDCH) is not carried by the RSL link. One link is required per TRX defined.

SAPI=62
is used for the Operations & Maintenance Link (OML). This link is used for supporting network TRXC management procedures.

The physical entities (TRX) that BSC communicates with at the BTS, via data links, are referred to as Terminal Equipment. A TEI/SAPI pair, unique within each physical connection identifies each data link. Each physical connection can support a number of data links.
Each TRX have one OML and one RSL signaling link. Additionally there is a CF signalling link to the DX function in the RBS2000. These links use the LAPD protocol:
  • The CF link is identified by the TEI value (configurable) and SAPI=62.
  • The OML link is identified by the TEI value for the TRX and SAPI=62.
  • The RSL link is identified by the TEI value for the TRX and SAPI=0.
  • The TRX TEI value is defined by the TRX position in the RBS cabinet.
The LAPD concentrator receives messages from several TRXs and sends these messages on one 64 kbit/s Abis time slot to BSC. The LAPD concentrator also receives messages on this Abis time slot from the BSC and distributes them to the TRXs.
Without LAPD Concentration and LAPD Multiplexing each 64 Kbits/s A-bis time slot can support signalling for only one TRX.
With LAPD Concentration each 64 Kbits/s A-bis time slot can support signalling for up to four TRXs. The allocation of bandwidth between the different TRXs sharing a 64 kbit/s A-bis time slot is dynamic: the concentration is implemented as separately addressed messages which are sent over the common path. This means both transmission delays are minimized - LAPD Concentration is superior to LAPD Multiplexing when it comes to delays and thoughput performance.


Remote OMT





The Remote OMT Over IP is used to remotely perform OMT functionality from a TCP/IP network connecting BSCs.
The Remote OMT Over IP is mainly used for:
  • Getting detailed information about an RBS 2000 - The information can be used to remotely verify that an RBS 2000 is correctly configured and to perform preventive maintenance.
  • Fault localization of an RBS 2000 - Experts can use the Remote OMT Over IP to perform fault localization and to guide service personnel at site
  • Restart of a whole RBS 2000 or a part of an RBS 2000 - The same type of restart that is achieved by pushing a reset button in an RBS 2000 can be performed with the Remote OMT Over IP. This may be useful in situations with abnormal RBS behavior
  • Retrieve detailed information about an RBS 2000 remotely from a TCP/IP network connecting BSCs.
  • Perform fault localization of an RBS 2000 remotely from a TCP/IP network connecting BSCs. This means that it will be easier to prepare for a site visit and it will be possible for experts to remotely guide service personnel at site.
  • It is possible for a BSC to simultaneously handle four Remote OMT Over IP sessions. (Only one Remote OMT Over IP can simultaneously be connected to one specific RBS).
  • Perform "hardware reset" of an RBS 2000 remotely from a TCP/IP network connecting BSCs
  • The signalling is embedded in the LAPD signalling. A whole time slot does not have to be allocated for the OMT signalling as for Remote OMT.
  • It is much easier to establish a connection for the OMT signalling as it is not needed to setup a path in the transmission network. Just an access to the IP network connected to the BSC is needed.
  • The Remote OMT Over IP does not have to be equipped with any special hardware equipment as for Remote OMT which have to be equipped with a special communication board to emulate an E1/T1 transmission link.

The Remote OMT Over IP is an optional feature activated by the BSC.
The Remote OMT Over IP user is required to make an authentication by providing a password to be able to make a connection to the RBS. The password is defined by the BSC operator at the setup of the feature. It is also possible to define how long time the feature shall be activated and also to define the IP-address which the calling Remote OMT Over IP is supposed to have.

Benefits
Remote OMT Over IP makes it possible to:
Benefits with Remote OMT Over IP compared to Remote OMT:

BTS Fault Alarm

Types of Fault Map
Internal Class 1A
Internal to BTS, affecting MO, within MO
Internal Class 1B
Internal to BTS, affecting MO, within MO environment
Internal Class 2A
Internal to BTS, not affecting MO, within MO
External Class 1
External to BTS and affecting MO
External Class 2
External to BTS not affecting MO


The alarm slogan is the description of the current alarm situation for an MO or TG. The alarm slogans 'BTS INTERNAL' and 'BTS EXTERNAL' each describe more than one alarm situation. The remaining alarm slogans each describe a unique alarm situation. This section describes how each alarm slogan should be interpreted.
TGC FAULT No active TGC application exists in the Transceiver Group.
PERMANENT FAULT A managed object is classified as being permanently faulty when fault situations have occurred, and have been cleared, a certain number of times within a certain period of time. Manual intervention is required to bring such equipment back into operation.
LOCAL MODE The BTS equipment is in Local Mode or the BTS equipment has changed from Local to Remote Mode and a fault exists in the communication link between the BSC and the BTS. Communication between the BSC and the BTS is not possible.
LMT INTERVENTION Local maintenance activities are being performed in the BTS.
LOOP TEST FAILED Test of the traffic carrying capabilities of the TS has failed.
BTS INTERNAL There is a fault internal to the BTS.
MAINS FAILURE There is a fault in the power supply to the BTS or one or more items of equipment within the BTS. Battery backup (where available) is in use. Escalation may occur if corrective action is not taken.
BTS EXTERNAL There is a fault external to the BTS.
OML FAULT There is a fault in the communications link between the BSC and BTS.
ABIS PATH UNAVAIL No transmission device exists between the BSC and BTS.
CON QUEUE CONGESTION At least one of the LAPD Concentrator concentration outlet queues has reached an unacceptable filling level.
TS SYNC FAULT Synchronization lost on uplink or downlink TRA or PCU channels.
FORLOPP RELEASE A fault has occurred within the BSC software leading to a Forlopp release. Automatic recovery procedures are taking place. Report to your Ericsson Support Office. Alternatively, this alarm is issued as an advisory following a command ordered Forlopp release of a TG. In either case, the alarm is automatically ceased following successful recovery.
OPERATOR CONDITION A condition has arisen due to operator intervention
BSC
Base Station Controller
BTS
Base Transceiver Station
CF
Central Functions
CON
LAPD Concentrator
DP
Digital Path
IS
Interface Switch
LAPD
Link Access Protocol for the D channel
LMT
Local Maintenance Terminal
MO
Managed Object
OML
Operation and Maintenance Link
PCU
Packet Control Unit
RBS
Radio Base Station
RX
Receiver
TF
Timing Function
TG
Transceiver Group
TGC
Transceiver Group Controller
TRA
Transcoder Rate Adaptor
TRXC
Transceiver Controller
TS
Timeslot
TX
Transmitter