ma_fail_from_ms

ma_fail_from_ms有几种可能：
MSC refuses the establishment of the SCCP connection through a Connection Refuse message.（MSC拒绝SCCP连接）
TCH Assignment Failures due to TCH blocking at the BSS.（因为拥塞而使TCH指配失败,此时统计为alloc_tch_fail）
The failure of the MS to access the target TCH channel with subsequent successful returning to the SDCCH channel.（未占上tch，返回sdcch）
TCH Assignment Failures (Lost MS) due to the failure of the mobile to access the target TCH channel and failure to re-establish on the SDCCH channel.(未占上tch，返回sdcch失败)
如何鉴别此类问题
The MSC normally responds a Connection Confirmed (CC) to the request of stablishment of the SCCP connection (CR). Nevertheless, if something happened in the MSC (e.g. software failure) or the CR message (e.g. protocol error), a Connection Refuse (CREF) may be returned representing failure of establishing the SCCP connection.
You can easily identify it via statistics. But, be aware of the fact that the MSC may return a CREF in response to the CR with L3 info of IMSI detach, which, in fact, can save the load on A interface.
If there is no TCH available or software error conditions existing in CRM or RRSM, the assignment procedure may also fail with the cause of TCH blocking, which can be measured by raw statistics MA_CMD_TO_MS_BLK（TCH拥塞统计）. Check cell status for possible reasons.
When a free TCH has been allocated by the CRM, the RRSM will send an Assignment Command to the MS. Meanwhile, it pegs MA_CMD_TO_MS（有TCH资源，而且向MS发送了指配命令）and starts a timer BSSMAP_T10 guarding for receipt of the Assignment Complete message. If the MS failed in tuning to the new TCH upon receipt the Assignment Command, it would revert to the SDCCH and return an Assignment Failure message, which causes the RRSM to stop the timer and pegs the counter MA_FAIL_FROM_MS（分配了TCH，MS却没有占上）.
If both Assignment Complete and Assignment Failure are not received by RRSM before the BSSMAP_T10 expiry, which means the SDCCH is lost while the assignment procedure is undergoing, the procedure aborts with no counters pegged. But, you could still trace the number of times it occurs by following formula, MA_CMD_TO_MS-INTRA_CELL_HO_SUC-MA_COMPLETE_TO_MSC-MA_FAIL_FRO M_MS. The reason why you have to deduct INTRA_CELL_HO_SUC is both MA_CMD_TO_MS and MA_FAIL_FROM_MS not only pegged by original assignment but intra_cell handovers. Meanwhile, you’ll probably see low TOTAL_CALLS compare to OK_ACC_PROC and high RF_LOSSES_SD.
Detailed analysis
如果CONN_REFUSED远远大于IMSI_DETACH,则establishment of SCCP connection 出现问题，进一步跟踪：
Filters
Connection Request (the LCF in which the BTS resides)
fil create tag 00100900h
Connection Confirm (the LCF in which the BTS resides)
fil create tag 00040902h
Connection Reject (the LCF in which the BTS resides)
fil create tag 00080903h
For detailed field description, please refer to ITU Q.713 and GSM specification 04.08/08.08
只通过统计定位问题
跟踪RSS到CP的消息流程是查明问题的快捷方式
Filters
Assignment Command (at the BTP):
fil create tag 0xxxx0201h msg[9] 6 msg[10] 2eh
Assignment Complete (at the BTP)
fil create tag 0xxxx0202h msg[9] 6 msg[10] 29h
Assignment Failure (at the BTP)
fil create tag 0xxxx0202h msg[9] 6 msg[10] 2fh
Remarks: Assignment Command is imbedded as layer 3 info. in RSS-CP message Data Request while Assignment Complete and Assignment Failure are in Data Indication.
Ma_Fail_From_MS/Total_calls的结果大于10%左右的时候，说明当小区资源管理器分配一个空闲TCH信道给手机用户后，手机用户占用不到这个载频。

通常其比例大于总时段呼叫总数的10%的情况下，可认为此小区存在硬件问题。

为判断是哪个载频存在问题，需要使用基站中过滤消息的功能，即根据话务信道分配命令，话务信道分配成功及话务信道分配失败三种信息间的关系来推断出手机无法占用信道的载频。

perl工具的应用
首先通过getpm的rawcel查出哪些小区的MA_FAIL_FROM_MS较高
收集RSS到CP的消息，通过超级终端登陆到BSC上，并capture the log file
例：
tty_rlogin YICBSC01G
chg_l
3stooges
4beatles
set_mmi exec_mon
rl 24 1015h ’（24＝站号＋1）
fil create tag 0xxxx0201h msg[9] 6 msg[10] 2eh
fil create tag 0xxxx0202h msg[9] 6 msg[10] 29h
fil create tag 0xxxx0202h msg[9] 6 msg[10] 2fh
fil start all
收集数据约20分钟，fil stop all
fil delete all
用perl分析问题出现在哪个频点上
例如将perl放在D盘根目录下，将收到的log文件例如site_name.txt放在perl/bin下,进入DOS操作系统模式，进入D:\perl\bin下，键入perl finder.txt site_name.txt
将有报告产生，便可以查出分配次数高的载频。

查找到RTF所在地载频，将载频更换。