Immediate Assignment Reject
Yes, it can happen that a cell has a weird behaviour at some point, and needs to berestarted.Actually, every time one measures a sudden change of QoS, the first step to do is toreset TRMs and the SUM, and possibly the TCU at BSC side.. Just to rule out apossible software failure and not spend too much time trying to find a logical causeto the problem :)Hello,immediate assignment reject is caused by sdcch congestion : if no SDCCH resourceis availble in the BTS, the BSC sends an immediate assignment reject.Can you give, at the busy hour, the following QOS indicators:1. nb of SDCCH requestsdistribution of types of sdcch requests (loc upd, ms orig, ms term, sms, etc.)2. nb of SDCCH rejected due to congestion3. nb of SDCCH allocated4. SDCCH erlang at busy hour5. SDCCH capacity of the cellDear All,Im facing high SDCCH Allocation and Assignment Failure in one cell. In the trace imgetting "Immediate Assgnment Reject". There is no SD congestion or over flow inthat cell. Please if anyone can let me know with the reason why it happens andwhats the solution for it.
Immediate assignment procedure
The IMMEDIATE ASSIGN message facilitates the assignment of the MS onto anSDCCH channel. Correspondingly, the IMMEDIATE ASSIGN REJECT messagefacilitates the refusal of the access. If the SDCCH reservation or activation fails, theBSC sends the IMMEDIATE ASSIGN REJECT message to the MS. The GSM timer T3101 supervises the immediate assignment procedure. The immediate assignment procedure is presented in the following figure:
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential 配建内颜同选（客伙在Locating Procedure for Assignment Problem Error assignment message A3129I:Failed Assignments (Invalid State) A3129J:Failed Assignments (Invalid Message) A3129E:Failed Assignments (CIC Unavailable) Page 4 Terrestrial resource abnormal/Cleared by MSC A3129B:Failed Assignments (First Assignment, Terrestrial Resource Request Failed) A3129N:Failed Assignments (Reconnection to Old Channels, Terrestrial Resource Request Failed) A3129H:Failed Assignments (Clear Commands Sent By MSC) A3129F:Failed Assignments (CIC Allocated) No TCH/CIC resource MSC faults Inappropriate BSC Configuration Poor Um Interface Quality Abnormal resource distribution A312A:Failed Assignments (First Assignment, No Channel Available in Assignment Procedure) A312L:Failed Assignments (Reconnection to Old Channels, No Channel Available in Assignment) A312K:Failed Assignments (First Assignment, No Channel Available in Directed Retry Procedure) A312M:Failed Assignments (Reconnection to Old Channels, No Channel Available in Directed Retry) A312F:Number of Assignment Failures (No Abis Resource Available) A3129S:Failed Assignments (Requested Speech Version Unavailable)