Call Trace in Abis

[前言]
用戶MS建立一通呼叫或使用某服務所產生的信令message之間的關連性有很多是非常隱微的，無法從信令message本身的名稱看出來，或是由IMSI/TMSI/P-TMSI等ID來辨識，因此如果沒有一個非常聰明的分析工具，工程師往往感到很頭痛，不知message之間如何由時間上與邏輯性來串聯起來，針對一個用戶的MS需求來分析所有的信令。

[Abis]

Scenario 1:MS發起的BTSM: P-Channel Required
[BTS --> BSC]
Conn:2 Line:1 TS:30 Subch:0 745 10:49:02.0835486
--------E1
VALID FRAME: 00 03 76 46 20 63 01 88 13 7A F1 D1 11 00
--------LAPD:
INFO
SAPI: 0 (0h) TEI: 1 (1h) C/R: 0 P/F: 0
N(R): 23H N(S): 3BH: 20 63 01 88 13 7A F1 D1 11 00
--------BTSM:
P-CHANNEL REQUIRED (GPRS) T=0
Channel Nr
- uplink CCCH (RACH)
- timeslot : 0
Req. Ref
- Est. cause : one phase packet access <- 理由
- used
- random reference : 2 (2h) <- 隨機碼
- T1' : 30 (1eh) <- 參數1
- T2 : 17 (11h) <- 參數2
- T3 : 14 (eh) <- 參數3
- Frame number : 39641 <- 參數4
Access Delay
- value : 0 (00h)
[EOM]

[BTS <-- BSC]
Conn:2 Line:1 TS:30 Subch:0 746 10:49:02.0885487
--------E1:
VALID FRAME: 00 03 01 78
--------LAPD:
RECEIVER READY
SAPI: 0 (0h) TEI: 1 (1h) C/R: 0 P/F: 0
N(R): 3CH
[EOM]

[BTS <-- BSC]
Conn:2 Line:1 TS:30 Subch:0 752 10:49:02.1405491
--------E1:
VALID FRAME
02 03 46 78 20 60 01 90 2B 17 2D 06 3F 10 0A 00 78 7A F1 D1 00 00 C9 08
00 28 2B 2B 2B 2B 2B 2B 2B FC 00 04
--------LAPD:
INFO
SAPI: 0 (0h) TEI: 1 (1h) C/R: 1 P/F: 0
N(R): 3CH N(S): 23H
20 60 01 90 2B 17 2D 06 3F 10 0A 00 78 7A F1 D1 00 00 C9 08 00 28 2B 2B
2B 2B 2B 2B 2B FC 00 04
--------BTSM:
P-IMM ASSIGN CCCH COMMAND (GPRS) T=0
Channel Nr
- downlink CCCH (PCH + AGCH)
- timeslot : 0
Full Imm. Ass. Info
- value (hex) : 2D 06 3F 10 0A 00 78
7A F1 D1 00 00 C9 08 00 28 2B 2B 2B
2B 2B 2B 2B
Message Sequence Id
- MSI value: 4 (4h)
--------RR:
IMMEDIATE ASSIGNMENT (RR)
L2 Pseudo Length: 0B
Skip Indicator: 00
RR management Protocol Discriminator: 06
Dedicated mode or TBF:
- TMA: No meaning
- down-link: No meaning
- T/D: 1 this message assigns a Temporary Block Flow (TBF)
Page Mode:
- PM: Normal paging
Packet Channel Description:
- Channel type: 01
- TN: 02
- TSC: 00
- ARFCN: 00 78
Request Reference:
- Est Cause: <- 理由(與P-Channel Required的理由相同)
One phase packet access with request for single timeslot uplink transmission; one PDCH is needed
- Random Reference: 2 (0x2) <- 隨機碼(與P-Channel Required的隨機碼相同)
- T1': 30 (0x1e) <- 參數1(與P-Channel Required的相同)
- T2: 17 (0x11) <- 參數2(與P-Channel Required的相同)
- T3: 14 (0xe) <- 參數3(與P-Channel Required的相同)
- Frame number : 39641 <- 參數4(與P-Channel Required的相同)
Timing advance value: 00
Mobile Allocation Length: 00
MA C: empty
IA Rest Octets:
- Packet Uplink Assignment:
- TFI Assignment: 04
- Polling: no action is required from MS
- USF: 04
- USF Granularity: 00
- Channel Coding Command: coding scheme 1, CS-1
- TLLI Block Channel Coding:
mobile station shall use CS-1 in GPRS TBF mode or MCS-1 in EGPRS TBF mode
- Gamma: GammaCH = 0 dB
- Timing Advance Index: 04
[EOM]

[BTS --> BSC]
Conn:2 Line:1 TS:30 Subch:0 753 10:49:02.1435492
--------E1:
VALID FRAME: 02 03 01 48
--------LAPD:
RECEIVER READY
SAPI: 0 (0h) TEI: 1 (1h) C/R: 1 P/F: 0
N(R): 24H
[EOM]

[BTS --> BSC]
Conn:2 Line:1 TS:30 Subch:0 765 10:49:02.2495499
--------E1:
VALID FRAME: 00 03 78 48 20 61 01 90 FC 00 04 08 F0 C8
--------LAPD:
INFO
SAPI: 0 (0h) TEI: 1 (1h) C/R: 0 P/F: 0
N(R): 24H N(S): 3CH: 20 61 01 90 FC 00 04 08 F0 C8
--------BTSM:
P-IMMEDIATE ASSIGN ACK (GPRS) T=0
Channel Nr
- downlink CCCH (PCH + AGCH)
- timeslot : 0
Message Sequence Id
- MSI value: 4 (4h)
Frame Number
- T1' : 30 (1eh)
- T2 : 8 (8h)
- T3 : 6 (6h)
- Frame number : 39684
[EOM]

070617r1版本