《[信息与通信]7号共路信令.ppt》由会员分享，可在线阅读，更多相关《[信息与通信]7号共路信令.ppt（94页珍藏版）》请在三一办公上搜索。
1、7号共路信令,徐名海南京邮电大学通信与信息工程学院,2023/8/2,2,提 纲,电路交换、报文交换与分组交换 SS7的基本概念 MTP TUP SCCP MAP,2023/8/2,3,交换方式(1)：电路交换,A B C D,t,电路交换（CS：Circuit Swtching)过程：连接建立信息传送连接释放特点：面向连接的物理通道（端到端）透明传送无差错控制措施过负荷时呼损率增加，但不影响已建立的呼叫,2023/8/2,4,交换方式(2)：报文交换,报文交换报文结构 首部中含地址信息存储转发(逐段行为)把收到的分组先放入缓存（暂时存储）；查找转发表，找出到某个目的地址应从哪个端口转发；把分
2、组送到适当的端口转发出去。时延较大时延构成：传输时延（链路）存储时延（结点）处理与排队时延（结点）,A B C D,t,2023/8/2,5,交换方式(3)：分组交换,分组交换将报文要传送的信息分为若干个分组（packet），每一个分组有一个头部，含有可供选路的信息和其他控制信息。减少了存储时间,2023/8/2,6,交换方式(3)：分组交换,分组交换的优点：动态分配传输带宽，对通信链路是逐段占用。以分组为传送单位和查找路由。不必先建立连接就能向其他主机发送分组；充分使用链路的带宽。完善的网络协议；自适应的路由选择协议使网络有很好的生存性。,A B C D,t,2023/8/2,7,交换方式(
3、3)：分组交换,分组交换的问题：分组在各结点存储转发时需要排队，这就会造成一定的时延。分组必须携带的首部（里面有必不可少的控制信息）也造成了一定的开销。分组长度的确定兼顾时延与开销,2023/8/2,8,交换方式,2023/8/2,9,通信服务的类型：面向连接服务/无连接服务,面向连接服务(Connection-Oriented)面向连接服务具有连接建立、数据传输和连接释放这三个阶段。无连接服务(ConnectionLess)两个实体之间的通信不需要先建立好连接。是一种不可靠的服务。这种服务常被描述为“尽最大努力交付”(best effort delivery)或“尽力而为”。,2023/8/
4、2,10,分组交换中的两种服务方式,虚电路方式 面向连接服务 逻辑连接 交换虚电路、永久虚电路数据报方式 无连接服务 每个分组根据目的地址独立选路,2023/8/2,11,虚电路服务方式,2023/8/2,12,数据包服务方式,2023/8/2,13,虚电路服务 VS 数据报服务,2023/8/2,14,电路交换VS分组交换,SS7的基本概念,SS6，SS7 CAS，CCS SS7 Structure Identification of Signaling Points and Trunks SS7 Signal Units and Primitives Acronyms,2023/8/2,1
5、5,SS6，SS7,mid-1970s-CCITT No.6,international network-Bell System,Common-channel interoffice signaling(CCIS)SS6:FDM(analog)/PCM(digital)second generation:SS7,CCITT Yellow Books(1981)application expanded:call control,ISDN several national versions defined-ANSI/BELLCORE,U.S.networks-British Telecoms Na
6、tional User Part,U.K.network,2023/8/2,16,CAS，CCS,In channel-associated signaling(CAS)systems,the signaling information for a trunk is carried by the trunk itself.In common-channel signaling(CCS),a common signaling link(SL)carries signaling messages for a number of trunks.CCS:much faster,more flexibl
7、e,Subscribers cannot access the CCS signaling links.,2023/8/2,17,SS7 Structure,2023/8/2,18,2023/8/2,19,Transfer of a TUP message(1)TUP message,(2)MTP3 message,(3)MSU,2023/8/2,20,Identification of Signaling Points,Identification of Trunks,2023/8/2,22,2023/8/2,23,2023/8/2,24,2023/8/2,25,2023/8/2,26,St
8、ructure of MTP2,2023/8/2,27,2023/8/2,28,2023/8/2,29,MTP3 Message Format,2023/8/2,30,2023/8/2,31,MTP3 Signal Network Management,2023/8/2,32,TUP,General Message Structure Call-Control Messages and Signals Basic Signaling Sequences,2023/8/2,33,2023/8/2,34,2023/8/2,35,2023/8/2,36,2023/8/2,37,2023/8/2,38
9、,2023/8/2,39,2023/8/2,40,2023/8/2,41,2023/8/2,42,2023/8/2,43,RLG-Release Guard:正常呼叫结束时的电路释放监护消息，前方局只有收到后向局发来的RLG，才能将此电路释放给新的呼叫使用。,SCCP-Signaling Connection Control Part,SCCP提出背景 SCCP结构与接口 SCCP消息与参数 SCCP Routing Control(SCRC),2023/8/2,44,SCCP提出背景,4级结构采用逐段转发的方式传送SS7，增大中间点的无效负荷，增加消息传送时延 根据DPC选路，必须知道每个目
10、的的信令点编码，PC不具有全局意义 SI识别消息用户，4bit，不适应业务增长需要 MTP指支持数据报传送方式，某些应用须采用虚电路方式 CCITT提出1984年SCCP分层，1988、1992完善增强,2023/8/2,45,2023/8/2,46,The SCCP Message Structure,2023/8/2,47,2023/8/2,48,2023/8/2,49,2023/8/2,50,2023/8/2,51,2023/8/2,52,Introduction to GSM-MAP,GSM Radio Channels Signaling Interfaces and Protoco
11、ls Signaling between mobile and network Layer 3 Messages on the Um Interface Operations related to location updating Operations for calls terminating at MS Operations and Procedures for originating calls,2023/8/2,54,2023/8/2,55,Signaling Interfaces and Protocols,Um and A interface Equipment entities
12、 and interfaces Identification of GSM entities Info.in SIM,HLR,VLR,EIR,and AUC,Um and A Interfaces,Um Interface(1/2),Physical Layer:this consists of those parts of the RF channels that contain signaling channels(SACCH,FACCH,BCCH,SCH,FCCH,PAGCH,RACH,and SDCCH).Data Link Layer:the protocol is known as
13、 LAPDm,and is a modified version of the link access protocol for D-channels of DSS1.Messages Layer:RR(无线资源管理),MM（移动管理）,CM（连接管理）,Um Interface(2/2),A Interface,Physical Layer:64kb/s channels Data Link Layer:MTP2 Message Layer:BSSAP(base station subsystem application part)DTAP BSSMAP,Transfer of RR mes
14、sages,Transfer of MM and CM messages,Equipment entities and interfaces(1/2),Equipment entities and interfaces(2/2),Identification of GSM entities,LAI:Location Area Identity MCC-MNC-LAC IMSI:International Mobile Station Identity MCC-MNC-MSIN(Mobile Station Identity Number)TMSI:Temporary Mobile Statio
15、n Identity(32bit)IMEI:International Mobile Equipment Identity(15-digit)MSRN:Mobile Station Roaming Number used by the fixed network to extend the call set-up to the MSC,Info.In SIM,Info.In HLR,Info.In VLR,Info.In AUC,Signaling between mobile and network,MS Initialization Idle MS Location Updating Se
16、t-up of a call Originated by MS Connection Set-up for Call Terminating at MS Release of Connection,MS Initialization,Idle MS,Location Updating,Call Originated by MS,Call Terminating at MS,Call Clearing,Layer 3 Messages on the Um Interface,Messages for RR Messages for MM Messages for CC,Messages for
17、RR,Assignment Command:network-MS,TACH Assignment Complete:MS-network,Resp.Channel Release:network-MS,release cause IE Channel Request:MS-network,SDCCH Cipher Mode Command:sent by the network on SDCCH Cipher Mode Complete:sent by MS on SDCCH Immediate Assignment:sent by the network on PAGCH,resp.to c
18、hannel req.Paging Request:sent by the network on PAGCH,informing an incoming call Paging Response:sent by the MS on SDCCH to confirm the receipt of a paging request System Information Messages:BCCH,Messages for MM,Authentication Request:sent by the network on SDCCH.RAND Authentication Response:resp.
19、,SRES CM Service Request:sent by MS on SDCCH IMSI Detach Indication:sent by MS on SDCCH,before power-down Location Updating Accept:sent by the network on SDCCH Location Updating Request:sent by MS on SDCCH TMSI Reallocation Command:sent by the network TMSI Reallocation Complete:sent by MS,Messages f
20、or CC,Alerting:MS-O,network;MS-T,MS Call Confirmed:sent by a called MS Call Proceeding:MS-O,by the network Connect:MS-O,network;MS-T,MS answered Connect Acknowledge:receipt of a connect message Disconnect:request the release of the connection Release:ack.a received disconnect message or indicate a n
21、etwork-initiated release Release Complete:ack.A release message Set-up:MS or the network,including:bearer capability,called party address,calling party address,etc.,Operations related to location updating,Operations for LU.Mobile is known at VLR Initial operations for LU.Mobile is not known at VLR,a
22、nd is identified by LAIs and TMSIs Initial operations for LU.Mobile is not known at VLR,and is identified by IMSI Subsequent operations for LU Final operations for LU,Operations for LU.Mobile is known at VLR,Initial operations for LU.Mobile is not known at VLR,and is identified by LAIs and TMSIs,Ini
23、tial operations for LU.Mobile is not known at VLR,and is identified by IMSI,Subsequent operations for LU,Final operations for LU,Operations for calls terminating at MS,Routing calls to the visited MSC Operations for terminating calls Terminating call procedures,Routing calls to the visited MSC(1/3),
24、Routing calls to the visited MSC(2/3),Routing calls to the visited MSC(3/3),Operations for terminating calls,MAP_SEND_ROUTING_INFORMATION MAP_PROVIDE_ROAMING_NUMBER MAP_SEND_INFO_FOR_INCOMING_CALL MAP_PAGE MAP_PROCESS_ACCESS_REQUEST MAP_COMPLETE_CALL,Obtaining MSRN,Operations for terminating calls,Operations for originating calls,
