In country A, BSS has a BSC6900 in Island B, and its transcoder is remote in city B beside the MSC. After the integration of BSC to MSC, a test BTS had been configured to perform the test call. It was asked from core engineers to define LAC and Cell ID of the BTS in MSC; core engineers claim that it is impossible to activate the BSC in MSC side and BSS application layer was not UP.
MTP2 link and MTP3 link were checked and were OK. The other solution was asking MSC guys to check their configuration.
In the next step we check the SCCP through the command DSP SSN, instantly we noticed that the SCCP is not OK.
Oddly there were not any alarm about this in alarm panel! It seems someone cleared the alarm “SCCP Subsystem Prohibited” manually. After double checking the configuration according the alarm we notice that there is no M3Rout defined from BSC to MSC.
1. ALM-21521 SCCP Subsystem Prohibited
Consequently, the following procedures were undertaken as handling process
After defining the LAC and Cell ID of the Test BTS in MSC it understood that BSC can’t be seen activated from MSC side , Consequently, the following procedures were undertaken as handling process:
1. Reset the Board of the BSC/GTC related to the A interface.
2. Check all the alarms of the BSC and decide if any is related to the problem of not have the BSC activated in the MSC.
3. Checking the SCCP status by executing the command DSP SSN; as the status of SCCP was prohibited the possible causes should be considered.
4. After configuring the M3RT the problem solved and the BSC activated in MSC and the test BTS get ready for test call.
Possible causes are as follows:
1. the configuration of BSC in MSC side is not complete.
2. The M3RT is not Configured correctly in BSC side.
3. There is no M3RT defined to MSC.
When BSS application is not up in MSC, after checking alarm log carefully and even the alarm history, the configuration have to be check from both the BSC and MSC point; and make sure about the definition of rout between two peer NEs.