BEGIN FORWARD SM其信令解码如下:
******** MTP (07/96)
******** MSU
******** <General Fields>
-0101111 Backward Sequence Number : 47
1------- Backward Indicator Bit : 1
-1111011 Forward Sequence Number : 123
0------- Forward Indicator Bit : 0
--111111 Length Indicator : 63 = LI -> Message Signal Unit
******** Service Information Octet
----0011 Service Indicator : 3 = Signaling Connection Control Part
--00---- Priority Indicator : 0
10------ Network Indicator : 2 = National network
******** Chinese SCCP
******** <General Fields>
******** Destination Point Code : 255-16-209 (郑州T局地址)
******** Originating Point Code : 255-16-241 (周口G网MSC地址)
----0010 Signalling Link Selection : 2
******** UNITDATA
******** Protocol class
----0001 Protocol class : 1
1000---- Message handling : 8 = return message on error
******** Called Party Address
-------0 Point code indicator : 0 = address contains no signalling point code
------1- SSN indicator : 1 = address contains a subsystem number
--0100-- Global title indicator : 4 = global title includes translation type,numbering plan,encoding scheme and nature of address indicator
-0------ Routing indicator : 0 = routing based on global title
0------- Reserved for national use : 0h
00001000 Subsystem number : 8 = MSC (Mobile Switching Centre)
00000000 Translation type : 0h
----0001 Encoding scheme : 1 = BCD, odd number of digits
0001---- Numbering plan : 1 = ISDN/telephony numbering plan (recommendation E.163 and E.164)
-0000100 Nature of address indicator : 4 = international number
******** Address information : 8613010761500
******** Calling Party Address
-------0 Point code indicator : 0 = address contains no signalling point code
------1- SSN indicator : 1 = address contains a subsystem number
--0100-- Global title indicator : 4 = global title includes translation type,numbering plan,encoding scheme and nature of address indicator
-0------ Routing indicator : 0 = routing based on global title
0------- Reserved for national use : 0h
00001000 Subsystem number : 8 = MSC (Mobile Switching Centre)
00000000 Translation type : 0h
----0010 Encoding scheme : 2 = BCD, even number of digits
0001---- Numbering plan : 1 = ISDN/telephony numbering plan (recommendation E.163 and E.164)
-0000100 Nature of address indicator : 4 = international number
******** Address information : 8613000754
******** Data : 62 81 CC 48 04 C9 00 BD 03 6B 1E 28 1C 06 07 00
: 11 86 05 01 01 01 A0 11 60 0F 80 02 07 80 A1 09
: ......
: 00 20 FF 0E 00 20 00 B0 22 34 00 B0 00 20 26 06
: 00 2E 00 20 4E 00 75 1F 5E 73 5B 89 00 2E 00 20h
******** GSM 09.02 - MAP (V 5.3.0)
******** BEGIN
******** Origination Transaction ID : C900BD03h
******** Dialogue Portion
******** Protocol : 0-0-17-773-1-1-1
******** Dialogue Request
******** Protocol Version : '1'b'1'b
******** Application Context Name : 0-4-0-0-1-0-21-2
******** Component Portion
******** Invoke
******** Invoke ID : 179
******** Operation Code
******** Local Value : 46 = forward-SM
******** Parameter
******** FORWARD SM
******** SM RP DA
******** Service Centre Address DA
******** Address String
----0001 Numbering plan : 1h = ISDN/Telephony Numbering Plan (Rec CCITT E.164)
-001---- Nature of address : 1h = international number
******** Number : 8613010761500f (短信中心号码)
******** SM RP OA
******** Msisdn
******** Address String
----0001 Numbering plan : 1h = ISDN/Telephony Numbering Plan (Rec CCITT E.164)
-001---- Nature of address : 1h = international number
******** Number : 8613017696701f (发送短信的用户号码)
******** SM RP UI
******** Data : 11 0D 0B 81 31 10 67 69 37 F1 32 08 A7 72 90 01
: 53 43 4E 07 98 97 66 1F 66 1F 7E D9 4F 60 00 3A
: ......
: 00 20 FF 0E 00 20 00 B0 22 34 00 B0 00 20 26 06
: 00 2E 00 20 4E 00 75 1F 5E 73 5B 89 00 2E 00 20h
以上消息是周MSC通过郑T局发送给短信中心的一个发送短消息的信令。由解码可以看出,此消息中包含源信令点地址、目地信令点地址、主叫号码、短信中心号码及所发送的短信内容,有了这些信息,用户发送的消息可以正确的传送到SC。
END的信令解码如下:
******** MTP (07/96)
******** MSU
******** <General Fields>
-1111011 Backward Sequence Number : 123
0------- Backward Indicator Bit : 0
-0110000 Forward Sequence Number : 48
1------- Forward Indicator Bit : 1
--111111 Length Indicator : 63 = LI -> Message Signal Unit
******** Service Information Octet
----0011 Service Indicator : 3 = Signaling Connection Control Part
--00---- Priority Indicator : 0
10------ Network Indicator : 2 = National network
******** Chinese SCCP
******** <General Fields>
******** Destination Point Code : 255-16-241 (目地信令点地址)
******** Originating Point Code : 255-16-209 (源信令点地址)
----0100 Signalling Link Selection : 4
******** UNITDATA
******** Protocol class
----0001 Protocol class : 1
1000---- Message handling : 8 = return message on error
******** Called Party Address
-------0 Point code indicator : 0 = address contains no signalling point code
------1- SSN indicator : 1 = address contains a subsystem number
--0100-- Global title indicator : 4 = global title includes translation type,numbering plan,encoding scheme and nature of address indicator
-1------ Routing indicator : 1 = routing based on DPC and SSN
0------- Reserved for national use : 0h
00001000 Subsystem number : 8 = MSC (Mobile Switching Centre)
00000000 Translation type : 0h
----0010 Encoding scheme : 2 = BCD, even number of digits
0001---- Numbering plan : 1 = ISDN/telephony numbering plan (recommendation E.163 and E.164)
-0000100 Nature of address indicator : 4 = international number
******** Address information : 8613000754 (周口GT值)
******** Calling Party Address
-------0 Point code indicator : 0 = address contains no signalling point code
------1- SSN indicator : 1 = address contains a subsystem number
--0100-- Global title indicator : 4 = global title includes translation type,numbering plan,encoding scheme and nature of address indicator
-0------ Routing indicator : 0 = routing based on global title
0------- Reserved for national use : 0h
00001000 Subsystem number : 8 = MSC (Mobile Switching Centre)
00000000 Translation type : 0h
----0001 Encoding scheme : 1 = BCD, odd number of digits
0001---- Numbering plan : 1 = ISDN/telephony numbering plan (recommendation E.163 and E.164)
-0000100 Nature of address indicator : 4 = international number
******** Address information : 8613010761500 (短信中心号码)
******** Data : 64 39 49 04 C9 00 BD 03 6B 2A 28 28 06 07 00 11
: 86 05 01 01 01 A0 1D 61 1B 80 02 07 80 A1 09 06
: 07 04 00 00 01 00 15 02 A2 03 02 01 00 A3 05 A1
: 03 02 01 00 6C 05 A2 03 02 01 B3h
******** GSM 09.02 - MAP (V 5.3.0)
******** END
******** Destination Transaction ID : C900BD03h
******** Dialogue Portion
******** Protocol : 0-0-17-773-1-1-1
******** Dialogue Response
******** Protocol Version : '1'b'1'b
******** Application Context Name : 0-4-0-0-1-0-21-2
******** Associate Result : 0 = accepted
******** Result Source Diagnostic
******** Dialogue Service User : 0 = null
******** Component Portion
******** Return Result Last
******** Invoke ID : 179
以上消息是短信中心通过T局发给周口MSC的信令,是对发送短消息成功与否的一个反馈。由信令解码可以看出,此消息中也包含源信令点地址、目地信令点地址、主叫号码(即短信中心号码)、被叫号码(平顶山MSC地址),从MAP层的消息可以看出,此次短信已经发送成功。
END SM DELIVERY FAILURE的信令解码如下:
******** MTP (07/96)
******** MSU
******** <General Fields>
-1110010 Backward Sequence Number : 114
0------- Backward Indicator Bit : 0
-0101001 Forward Sequence Number : 41
1------- Forward Indicator Bit : 1
--111111 Length Indicator : 63 = LI -> Message Signal Unit
******** Service Information Octet
----0011 Service Indicator : 3 = Signaling Connection Control Part
--00---- Priority Indicator : 0
10------ Network Indicator : 2 = National network
******** Chinese SCCP
******** <General Fields>
******** Destination Point Code : 255-16-241 (目地信令点地址)
******** Originating Point Code : 255-16-209 (源信令点地址)
----0000 Signalling Link Selection : 0
******** UNITDATA
******** Protocol class
----0001 Protocol class : 1
1000---- Message handling : 8 = return message on error
******** Called Party Address
-------0 Point code indicator : 0 = address contains no signalling point code
------1- SSN indicator : 1 = address contains a subsystem number
--0100-- Global title indicator : 4 = global title includes translation type,numbering plan,encoding scheme and nature of address indicator
-1------ Routing indicator : 1 = routing based on DPC and SSN
0------- Reserved for national use : 0h
00001000 Subsystem number : 8 = MSC (Mobile Switching Centre)
00000000 Translation type : 0h
----0010 Encoding scheme : 2 = BCD, even number of digits
0001---- Numbering plan : 1 = ISDN/telephony numbering plan (recommendation E.163 and E.164)
-0000100 Nature of address indicator : 4 = international number
******** Address information : 8613000754 (周口MSC的GT值)
******** Calling Party Address
-------0 Point code indicator : 0 = address contains no signalling point code
------1- SSN indicator : 1 = address contains a subsystem number
--0100-- Global title indicator : 4 = global title includes translation type,numbering plan,encoding scheme and nature of address indicator
-0------ Routing indicator : 0 = routing based on global title
0------- Reserved for national use : 0h
00001000 Subsystem number : 8 = MSC (Mobile Switching Centre)
00000000 Translation type : 0h
----0001 Encoding scheme : 1 = BCD, odd number of digits
0001---- Numbering plan : 1 = ISDN/telephony numbering plan (recommendation E.163 and E.164)
-0000100 Nature of address indicator : 4 = international number
******** Address information : 8613010761500 (短信中心号码)
******** Data : 64 45 49 04 B7 00 73 08 6B 2A 28 28 06 07 00 11
: 86 05 01 01 01 A0 1D 61 1B 80 02 07 80 A1 09 06
: 07 04 00 00 01 00 15 02 A2 03 02 01 00 A3 05 A1
: 03 02 01 00 6C 11 A3 0F 02 01 A3 02 01 20 30 07
: 0A 01 06 04 02 01 C1h
******** GSM 09.02 - MAP (V 5.3.0)
******** END
******** Destination Transaction ID : B7007308h
******** Dialogue Portion
******** Protocol : 0-0-17-773-1-1-1
******** Dialogue Response
******** Protocol Version : '1'b'1'b
******** Application Context Name : 0-4-0-0-1-0-21-2
******** Associate Result : 0 = accepted
******** Result Source Diagnostic
******** Dialogue Service User : 0 = null
******** Component Portion
******** Return Error
******** Invoke ID : 163
******** Error Code
******** Local Error Value : 32 = sM-Delivery-Failure
******** Parameter
******** SM DELIVERY FAILURE ERROR
******** SM Delivery Failure Cause With Diagnostic
******** SM Enumerated Delivery Failure Cause : 6 = subscriber-Not-SC-Subscriber(失败原因)
******** Data : 01 C1h
以上消息是短信中心发送给周口MSC的消息,它表明了此次短信未送成功,并给出了未送成功的原因。从MAP层消息可以看出,不成功的原因是此用户不是一个SC的合法用户。
5.2.2 接收短消息信令分析
移动终结短消息的过程与移动用户被叫的过程类似,包括取路由信息,寻呼,接入和寻呼响应,鉴权加密,短消息传送,最后向短消息中心报告接受结果,这个结果经IW_MSC分别送HLR和短消息中心,由短消息中心回送始发短消息用户。下图为移动终结短消息的流程图。
1-短消息
2-MAP-SEND-ROUTING-INFO-FOR-SM
3-MAP-SEND-ROUTING-INFO-FOR-SM-ACK
4-MAP-FORWARD-SHORT-MESSAGE
5-MAP-SEND-INFO-FOR-MT-SMS
6-MAP-PAGE/MAP-SEARCH-FOR-MOBILE-SUBSCRIBER
7-寻呼
8-寻呼响应
9-MAP-PROCESS-ACCESS-REQUEST-ACK和MAP-SEARCH-FOR-MOBILE-SUBSCRIBER-ACK
10-MAP-SEND-INFO-FOR-MT-SMS-ACK
11-短消息
12-短消息证实
13-MAP-FORWARD-SHORT-MESSAGE-ACK
14-短消息证
当短消息中心要向GSM移动用户发短消息时,先要建立“SM-TP SMS-DELEVER”消息。这条消息中包括一组信息,其中特别应包含用户消息的内容,原发者的识别符以及短消息业务中心收到该短消息的时间。短消息中心把此消息传送给与中心相连的关口站。关口站根据收到MSISDN就向相关的HLR查询,所用的消息名称是“送短消息路由信息(SEND ROUTING INGO FOR SHORT MESSAGE)”。其回答所用的消息名称是“送短消息路由信息的结果(SEND ROUTING INFO FOR SHORT MESSAGE RESULT)”,其中包含了被送用户的MSC/VLR的SS7信令地址。如果当时已经知道被送用户为不可及,发回的消息可以是“拒绝”。
关口站用SS7地址向有关的MSC传递消息,再由MSC投递到移动台,如果与移动台之间不存在信令路径就需建立一条这种路径。向移动台投递的消息存入SIM卡中,SIM有一定的存储容量,如果SIM卡的容量已经用足,就通知网络端,网络端可把这种情况作为移动台不可及处理,而把短消息暂时存放起来。一旦移动台的存储容量能够再容纳新的消息时也会通知网络端,网络端能够把原先存放的消息再投递给移动台。
为了提高短消息业务的服务质量使得用户更为满意,在移动台处不可及的情况下,要让消息不丢失,并采取措施尽快把消息投递给用户。投递的消息如没有得到确认,在一段时间内仍应继续记存在短消息业务中心,一旦用户恢复了与网络的联系了与网络的联系,消息可立即投递给用户。
我们观测周口MSC与郑T局间的信令流程如下:
由上图可看出,短信接收的信令与短信发送的信令形式相似,但其所含的内容不同。
BEGIN FORWARD SM的信令解码如下:
******** MTP (07/96)
******** MSU
******** <General Fields>
-0000010 Backward Sequence Number : 2
0------- Backward Indicator Bit : 0
-0000010 Forward Sequence Number : 2
1------- Forward Indicator Bit : 1
--111111 Length Indicator : 63 = LI -> Message Signal Unit
******** Service Information Octet
----0011 Service Indicator : 3 = Signaling Connection Control Part
--00---- Priority Indicator : 0
10------ Network Indicator : 2 = National network
******** Chinese SCCP
******** <General Fields>
******** Destination Point Code : 255-16-241 (周口MSC的GT值)
******** Originating Point Code : 255-16-209 (郑州T局)
----1010 Signalling Link Selection : 10
******** UNITDATA
******** Protocol class
----0001 Protocol class : 1
1000---- Message handling : 8 = return message on error
******** Called Party Address
-------0 Point code indicator : 0 = address contains no signalling point code
------1- SSN indicator : 1 = address contains a subsystem number
--0100-- Global title indicator : 4 = global title includes translation type,numbering plan,encoding scheme and nature of address indicator
-1------ Routing indicator : 1 = routing based on DPC and SSN
0------- Reserved for national use : 0h
00001000 Subsystem number : 8 = MSC (Mobile Switching Centre)
00000000 Translation type : 0h
----0010 Encoding scheme : 2 = BCD, even number of digits
0001---- Numbering plan : 1 = ISDN/telephony numbering plan (recommendation E.163 and E.164)
-0000100 Nature of address indicator : 4 = international number
******** Address information : 8613000754 (周口MSC的GT值)
******** Calling Party Address
-------0 Point code indicator : 0 = address contains no signalling point code
------1- SSN indicator : 1 = address contains a subsystem number
--0100-- Global title indicator : 4 = global title includes translation type,numbering plan,encoding scheme and nature of address indicator
-0------ Routing indicator : 0 = routing based on global title
0------- Reserved for national use : 0h
00001000 Subsystem number : 8 = MSC (Mobile Switching Centre)
00000000 Translation type : 0h
----0001 Encoding scheme : 1 = BCD, odd number of digits
0001---- Numbering plan : 1 = ISDN/telephony numbering plan (recommendation E.163 and E.164)
-0000100 Nature of address indicator : 4 = international number
******** Address information : 8613010761500 (短信中心号码)
******** Data : 62 81 A7 48 04 01 0C 12 00 6C 81 9E A1 81 9B 02
: 01 5E 02 01 2E 30 80 80 08 64 00 11 07 07 52 23
: ......
: 00 31 00 30 00 30 00 2C 6B 22 8F CE 4F 7F 75 28
: 80 54 90 1A 62 4B 67 3A 54 7C 00 2E 00 00 00 00h
******** GSM 09.02 - MAP (V 5.3.0)
******** BEGIN
******** Origination Transaction ID : 10C1200h
******** Component Portion
******** Invoke
******** Invoke ID : 94
******** Operation Code
******** Local Value : 46 = forward-SM
******** Parameter
******** FORWARD SM
******** SM RP DA
******** IMSI : 460011707025322f(被叫用户IMSI)
******** SM RP OA
******** Service Centre Address OA
******** Address String
----0001 Numbering plan : 1h = ISDN/Telephony Numbering Plan (Rec CCITT E.164)
-001---- Nature of address : 1h = international number
******** Number : 8613010761500f
******** SM RP UI
******** Data : 00 04 81 88 88 3B 08 20 11 10 61 70 83 00 6C 00
: 32 00 30 00 30 00 32 5E 74 00 31 00 31 67 08 00
: ......
: 00 37 00 31 00 30 00 30 00 2C 6B 22 8F CE 4F 7F
: 75 28 80 54 90 1A 62 4B 67 3A 54 7C 00 2E 00 00h
由以上信令解码可以看出,短信中心经郑州T局发送给周口MSC的消息中,包含了源信令点地址、目地信令点地址、被叫用户的IMSI及所要发送的短消息内容。
若短信发送成功,则周MSC回送给郑T局成功消息(END消息中包含)。若短信发送不成功,其原因有好几种。
其一,信令解码如下:
******** MTP (07/96)
******** MSU
******** <General Fields>
-1100010 Backward Sequence Number : 98
1------- Backward Indicator Bit : 1
-1001101 Forward Sequence Number : 77
0------- Forward Indicator Bit : 0
--111000 Length Indicator : 56 = LI -> Message Signal Unit
******** Service Information Octet
----0011 Service Indicator : 3 = Signaling Connection Control Part
--00---- Priority Indicator : 0
10------ Network Indicator : 2 = National network
******** Chinese SCCP
******** <General Fields>
******** Destination Point Code : 255-16-209
******** Originating Point Code : 255-16-241
----0100 Signalling Link Selection : 4
******** UNITDATA
******** Protocol class
----0001 Protocol class : 1
1000---- Message handling : 8 = return message on error
******** Called Party Address
-------0 Point code indicator : 0 = address contains no signalling point code
------1- SSN indicator : 1 = address contains a subsystem number
--0100-- Global title indicator : 4 = global title includes translation type,numbering plan,encoding scheme and nature of address indicator
-0------ Routing indicator : 0 = routing based on global title
0------- Reserved for national use : 0h
00001000 Subsystem number : 8 = MSC (Mobile Switching Centre)
00000000 Translation type : 0h
----0001 Encoding scheme : 1 = BCD, odd number of digits
0001---- Numbering plan : 1 = ISDN/telephony numbering plan (recommendation E.163 and E.164)
-0000100 Nature of address indicator : 4 = international number
******** Address information : 8613010761500
******** Calling Party Address
-------0 Point code indicator : 0 = address contains no signalling point code
------1- SSN indicator : 1 = address contains a subsystem number
--0100-- Global title indicator : 4 = global title includes translation type,numbering plan,encoding scheme and nature of address indicator
-0------ Routing indicator : 0 = routing based on global title
0------- Reserved for national use : 0h
00001000 Subsystem number : 8 = MSC (Mobile Switching Centre)
00000000 Translation type : 0h
----0010 Encoding scheme : 2 = BCD, even number of digits
0001---- Numbering plan : 1 = ISDN/telephony numbering plan (recommendation E.163 and E.164)
-0000100 Nature of address indicator : 4 = international number
******** Address information : 8613000754
******** Data : 64 10 49 04 01 76 0C 00 6C 08 A3 06 02 01 51 02
: 01 1Bh
******** GSM 09.02 - MAP (V 5.3.0)
******** END
******** Destination Transaction ID : 1760C00h
******** Component Portion
******** Return Error
******** Invoke ID : 81
******** Error Code
******** Local Error Value : 27 = absent-Subscriber(失败原因)
以上是一个短信未发送成功的消息,此次短信未送成功的原因包含在END信令中。从MAP层消息可以看出,不成功原因是用户缺席(即找不到用户)。
其二,信令解码如下:
******** MTP (07/96)
******** MSU
******** <General Fields>
-1111111 Backward Sequence Number : 127
0------- Backward Indicator Bit : 0
-0111010 Forward Sequence Number : 58
1------- Forward Indicator Bit : 1
--111011 Length Indicator : 59 = LI -> Message Signal Unit
******** Service Information Octet
----0011 Service Indicator : 3 = Signaling Connection Control Part
--00---- Priority Indicator : 0
10------ Network Indicator : 2 = National network
******** Chinese SCCP
******** <General Fields>
******** Destination Point Code : 255-16-208
******** Originating Point Code : 255-16-241
----1001 Signalling Link Selection : 9
******** UNITDATA
******** Protocol class
----0001 Protocol class : 1
1000---- Message handling : 8 = return message on error
******** Called Party Address
-------0 Point code indicator : 0 = address contains no signalling point code
------1- SSN indicator : 1 = address contains a subsystem number
--0100-- Global title indicator : 4 = global title includes translation type,numbering plan,encoding scheme and nature of address indicator
-0------ Routing indicator : 0 = routing based on global title
0------- Reserved for national use : 0h
00001000 Subsystem number : 8 = MSC (Mobile Switching Centre)
00000000 Translation type : 0h
----0001 Encoding scheme : 1 = BCD, odd number of digits
0001---- Numbering plan : 1 = ISDN/telephony numbering plan (recommendation E.163 and E.164)
-0000100 Nature of address indicator : 4 = international number
******** Address information : 8613010761500
******** Calling Party Address
-------0 Point code indicator : 0 = address contains no signalling point code
------1- SSN indicator : 1 = address contains a subsystem number
--0100-- Global title indicator : 4 = global title includes translation type,numbering plan,encoding scheme and nature of address indicator
-0------ Routing indicator : 0 = routing based on global title
0------- Reserved for national use : 0h
00001000 Subsystem number : 8 = MSC (Mobile Switching Centre)
00000000 Translation type : 0h
----0010 Encoding scheme : 2 = BCD, even number of digits
0001---- Numbering plan : 1 = ISDN/telephony numbering plan (recommendation E.163 and E.164)
-0000100 Nature of address indicator : 4 = international number
******** Address information : 8613000754
******** Data : 64 13 49 04 01 0C 12 00 6C 0B A3 09 02 01 5E 02
: 01 20 0A 01 00h
******** GSM 09.02 - MAP (V 5.3.0)
******** END
******** Destination Transaction ID : 10C1200h
******** Component Portion
******** Return Error
******** Invoke ID : 94
******** Error Code
******** Local Error Value : 32 = sM-Delivery-Failure
******** Parameter
******** SM DELIVERY FAILURE ERROR
******** SM Enumerated Delivery Failure Cause : 0 = memory-Capacity-Exceeded (失败原因)
以上是另一个短信未发送成功的消息。由MAP层消息可以看出,不成功原因是由于被叫用户的存储容量过限。
小结:经过我们对短消息的信令分析,我们才发现原来由于周口新开500部IP无线公话,正是由于这批无线公话其数据设置有问题,才影响我地短信发送成功率突然下降。而它并不影响本地其它手机的短信发送,所以用普通手机发送短信仍可发送成功。
5.3位置更新信令分析
在GSM系统中有三个地方需要知道位置信息,即HLR、VLR和MS(或SIM卡)。当这个信息发生变化时,需要保持三者的一致。
当MS发现某个LA能对其提供更好的业务时,则通知新小区所属MSC/VLR。如果原LA与新LA都属于同一个MSC/VLR时,则可以简单地在VLR中修改;如果不属于同一个MSC/VLR时,新MSC/VLR就要转向HLR,要求获取该MS的数据。HLR在送出新MSC/VLR所需信息的同时,通知原MSC/VLR删除原注册,并在新MSC/VLR中注册该MS。
MS与MSC之间的位置更新由MS发起。MS向MSC发“RIL-3-MM位置更新请求”消息,其中含识别该用户的主要信息。如果MS已在该MSC/VLR注册,MSC返回一个肯定的回答。如果MS不在该MSC/VLR,则需要与相应的HLR联系。通过MS的IMSI标识,MSC就可以确定它的归属HLR。MSC/VLR通过CCS.7信令把MS的位置更新请求送到该HLR,从HLR可以得到有关MS理详细的信息。在业务接收的情况下,MSC/VLR答以“RIL3-MM位置更新接受”,表示对新LA的注册有效;反之,则应以“RIL3-MM位置更新拒绝”,其原因可能是“PLMN不允许”、“LA不允许”等。