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1、1,Wireless and Mobile All-IP Networks,Yi-Bing Lin and Ai-Chun Panglinycsie.nctu.edu.tw,2,Contents 1/3,Chapter 1:Short Message Service and IP Network IntegrationChapter 2:Mobility Management for GPRS and UMTSChapter 3:Session Management for Serving GPRS Support NodeChapter 4:Session Management for Ga
2、teway GPRS Support NodeChapter 5:Serving Radio Network Controller Relocation for UMTS,3,Contents 2/3,Chapter 6:UMTS and cdma2000 Mobile Core NetworksChapter 7:UMTS Charging ProtocolChapter 8:Mobile All-IP Network SignalingChapter 9:UMTS Security and Availability IssuesChapter 10:VoIP for the Non-All
3、-IP Mobile NetworksChapter 11:Multicast for Mobile Multimedia Messaging ServiceChapter 12:Session Initiation Protocol,4,Contents 3/3,Chapter 13:Mobile Number PortabilityChapter 14:Integration and WLAN and Cellular NetworksChapter 15:UMTS All-IP NetworkChapter 16:Issues on IP Multimedia Core Network
4、SubsystemChapter 17:A Proxy-based Mobile Service Platform,5,Chapter 1:Short Message Service and IP Network Integration,GSM SMS Network Architecture,6,SMS-IP Integration:SM-SC-based,Mobile Network,SM-SC,Gateway,IP Network,In most commercial implementations,SMS and IP networks are integrated through S
5、M-SC.,7,NCTU-SMS,8,iSMS,9,Mobility and Session Management,Three types of mobility:radio mobility,core network mobility and IP mobilityRadio mobility supports handoff of a mobile user during conversationCore network mobility provides tunnel-related management for packet re-routing in the core network
6、 due to user movementIP mobility allows the mobile user to change the access point of IP connectivity without losing ongoing sessions.Session management maintains the routing path for a communication session,and provides packet routing functions including IP address assignment and QoS setting.,10,Ch
7、apter 2:Mobility Management for GPRS and UMTS,11,LAs,RAs,URAs,and Cells,12,Chapter 3:Session Management for Serving GPRS Support Node,13,Chapter 4:Session Management for Gateway GPRS Support Node,The GGSN plays the role as a gateway,which controls user data sessions and transfers the data packets be
8、tween the UMTS network and the external PDN.The meta functions implemented in the GGSN are described as follows:network access control,packet routing and transfer,and mobility management.,14,Access Point Name(APN),15,IP Address Allocation,16,Serving RNC,DriftRNC,Serving RNC,Chapter 5:Serving Radio N
9、etwork Controller Relocation for UMTS,17,Lossless SRNC Relocation,In 3GPP TS 23.060,a lossless SRNC relocation procedure was proposed for non-real-time data services.1.The source RNC first stops transmitting downlink packets to the UE,and then forwards the next packets to the target RNC via a GTP tu
10、nnel between the two RNCs.2.The target RNC stores all IP packets forwarded from the source RNC.3.After taking over the SRNC role,the target RNC restarts the downlink data transmission to the UE.No packet is lost during the SRNC switching period.Real-time data transmission is not supported because th
11、e IP data traffic will be suspended for a long time during SRNC switching.,18,Fast SRNC Relocation Stage I,Stage I(the same as Stage I in SD)initiates SRNC relocation.The IP packets are delivered through the old path:UENode B2target RNC source RNCSGSN1GGSNSteps 1 and 2:Source RNC initiates SRNC relo
12、cation by sending Relocation_ Required to SGSN1.Step 3:SGSN1 sends Forward_Relocation_ Request to request SGSN2 to allocate the resources for the UE.Step 4:SGSN2 send Relocation_Request with RAB parameters to the target RNC.After all necessary resources are allocated,the target RNC send Relocation_R
13、equest_ Acknowledge to SGSN2.,19,Fast SRNC Relocation Stage II,GGSN routes the downlink packets to the old path receiving Update_PDP_Context_ Request.After GGSN has received the message,the downlink packets are routed to the new path GGSNSGSN2target RNC.The“new”packets arriving at the target RNC are
14、 buffered until the target RNC takes over the SRNC role.Step 5:SGSN2 sends Update_PDP_Context_ Request to GGSN.GGSN updates the corresponding PDP context,and the downlink packet routing path is switched from the old path to the new path.Steps 6-7:SGSN2 informs SGSN1 that all resources for the UE are
15、 allocated.SGSN1 forwards this information to the source RNC.,20,Fast SRNC Relocation Stage III,The Iur link(i.e.,the old path)disconnected.The“old”downlink packets arriving at the source RNC later than Step 7(Relocation_Command)are dropped.The SRNC role is switched from the source RNC to the target
16、 RNC.Step 8:The source RNC transfers SRNS context(e.g.,QoS profile)to the target RNC.Steps 9 and 10:The target RNC informs SGSN2 that the target RNC will become the SRNC.At the same time,the target RNC triggers the UE to send the uplink IP packets to the target RNC.,21,Fast SRNC Relocation Stage IV,
17、The target RNC informs the source RNC that SRNC relocation is successfully performed.Then the source RNC releases the resources for the UE.Step 11:The target RNC indicates the completion of the relocation procedure to SGSN2,and SGSN2 forwards this information to SGSN1.Step 12:SGSN1 requests the sour
18、ce RNC to release the resources allocated for the old path.,22,Chapter 6:UMTS and cdma2000 Mobile Core Networks,UMTS and cdma2000 are two major standards for 3G mobile telecommunication.Two important functionalities of mobile core network are mobility management and session management.This chapter d
19、escribes these two functionalities for UMTS and cdma2000,and compare the design guidelines for these two 3G technologies.,23,cdma2000 Architecture,24,cdma2000 CS Domain,BSC connects to the core network through the SDU.The SDU distributes the circuit switched traffic(e.g.,voice)to the MSC.A1 interfac
20、e supports call control and mobility management between MSC and BSC.A2 and A5 interfaces support user traffic and circuit switched data traffic between MSC and BSC.,25,cdma2000 PS Domain,The SDU distributes the packet switched traffic to PCF and then to the PDSN.Interfaces A8 and A9 support packet s
21、witched data and signaling between PCF and SDU,respectively.Interfaces A10 and A11(R-P interface)support packet switched data and signaling between PCF and PDSN.GRE tunnel is used for data routing in A10 with standard IP QoS.MIP is used for signaling routing in A11.The R-P interface also supports PC
22、F handoff(inter or intra PDSN).,26,PDSN,Maintaining link-layer sessions to the MSsSupporting packet compression and packet filtering before the packets are delivered through the air interfaceProviding IP functionality to the mobile network,which routes IP datagrams to the PDN with differentiated ser
23、vice supportInteracting with AAA to provide IP authentication,authorization and accounting supportActing a MIP FA in the mobile networkThe interfaces among the PDN nodes(i.e.,PDSN,HA,AAA)follow the IETF standards.,27,cdma2000 Control Plane,28,UMTS Control Plane,29,cdma2000 User Plane,30,UMTS User Pl
24、ane,31,Protocol Stacks 1/2,The control plane carries out tasks for MM/SM/SMS.In cdma2000,the mobility and session tasks are based on the same lower layer protocol(IP based protocols)for user data transportation.In UMTS,the lower layer protocols supporting MM/SM tasks in the control plane are differe
25、nt from the lower layer protocols in the user plane.The signaling path between MS and SGSN consists of an RRC connection between MS and UTRAN,and an Iu connection between UTRAN and SGSN.,32,Protocol Stacks 2/2,In UMTS,the PS domain services are supported by PDCP in the user plane.PDCP contains compr
26、ession methods,which provide better spectral efficiency for IP packets transmission over the radio.In cdma2000,the header and payload compression mechanism is provided by PPP between MS and PDSN.Both UMTS RLC and cdma2000 LAC provide segmentation and retransmission services for user and control data
27、.cdma2000 LAC supports authentication functionality for wireless access,which is equivalent to GPRS transport layer authentication in UMTS.,33,PPP,In both control and user planes for cdma2000,PPP is carried over the LAC/MAC,and R-P tunnels are utilized to establish the connection between an MS and t
28、he PDSN.In cdma2000,a PPP connection is equivalent to a packet data session,which is comparable to the UMTS PDP context.In the UMTS control plane,no PPP/IP connection is established between MS and SGSN.Signaling is carried over the RRC and Iu connections.UMTS user plane provides two alternatives for
29、 IP services.IP is supported by non-PPP lower layer protocols.IP is supported by PPP.Dial-up applicationMobile IP is introduced to UMTS,34,Chapter 7:UMTS Charging Protocol,The GTP protocol is used for communications between a GSN and a CG,which can be implemented over UDP/IP or TCP/IP.Above the GTP
30、protocol,a Charging Agent(or CDR sender)is implemented in the GSN and a Charging Server is implemented in the CG.,35,The GTP Service Model,Our GTP service model follows the GSM Mobile Application Part(MAP)service model.A GSN communicates with a CG through a dialog by invoking GTP service primitives.
31、A service primitive can be one of four types:Request(REQ)Indication(IND)Response(RSP)Confirm(CNF),36,GTP Connection Setup,Before a GSN can send CDRs to a CG,a GTP connection must be established between the charging agent in the GSN and the charging server in the CG.,37,GTP CDR Transfer,The charging
32、agent is responsible for CDR generation in a GSN.The CDRs are encoded using,for example,the ASN.1 format defined in 3GPP 32.215.The charging server is responsible for decoding the CDRs and returns the processing results to the GSN.,38,GTP Failure Detection,In a GSN,an entry in the CG list represents
33、 a GTP connection to a CG.The CG Address attribute identifies the CG connected to the GSN.The Status attribute indicates if the connection is“active”or“inactive”.The Charging Packet Ack Wait Time Tr is the maximum elapsed time the GSN is allowed to wait for the acknowledgement of a charging packet.T
34、he Maximum Number of Charging Packet Tries L is the number of attempts(including the first attempt and the retries)the GSN is allowed to send a charging packet.The Maximum Number of Unsuccessful Deliveries K is the maximum number of consecutive failed deliveries that are attempted before the GSN con
35、siders a connection failure occurs.The Unsuccessful Delivery Counter NK attribute records the number of the consecutive failed delivery attempts.The Unacknowledged Buffer stores a copy of each GTP message that has been sent to the CG but has not been acknowledged.A record in the unacknowledged buffe
36、r consists of an Expiry Timestamp te,the Charging Packet Try Counter NL and an unacknowledged GTP message.,39,Path Failure Detection Algorithm,Step 1.After the connection setup procedure is complete,both NL and NK are set to 0,and the Status is set to“active”.At this point,the GSN can send GTP messa
37、ges to the CG.Step 2.When a GTP message is sent from the GSN to the CG at time t,a copy of the message is stored in the unacknowledged buffer,where the expiry timestamp is set to te=t+Tr.Step 3.If the GSN has received the acknowledgement from the CG before te,both NL and NK are set to 0.Step 4.If th
38、e GSN has not received the acknowledgement from the CG before te,NL is incremented by 1.If NL=L,then the charging packet delivery is considered failed.NK is incremented by 1.Step 5.If NK=K,then the GTP connection is considered failed.The Status is set to“inactive”.,The Path Failure Detection Algorit
39、hm(PFDA)detects path failure between the GSN and the CG.PFDA works as follows:,40,Chapter 8:Mobile All-IP Network Signaling,Traditional SS7 signaling is implemented in MTP-based network,which is utilized in the existing mobile networks including GSM and GPRS.In UMTS all-IP architecture,the SS7 signa
40、ling will be carried by IP-based network.The low costs and the efficiencies for carriers to maintain a single,unified telecommunications network,guarantee that all telephony services will eventually be delivered over IP.This chapter describes design and implementation of the IP-based network signali
41、ng for mobile all-IP network.,41,SS7 Architecture,Service Switching Point(SSP)is a telephony switch that performs call processing.Service Control Point(SCP)contains databases for providing enhanced services.Signal Transfer Point(STP)is a switch that relays SS7 messages between SSPs and SCPs.,42,Acce
42、ss Links(A-links)connect the SSP/STP or the SCP/STP pairs.Bridge Links(B-links)connect STPs in different pairs.Cross Links(C-links)connect mated STPs in a pair.Diagonal Links(D-links)are the same as the B-links except that the connected STPs belong to different SS7 networks.Extended Links(E-links)pr
43、ovide extra connectivity between an SSP and the STPs other than its home STP.Fully-Associated Links(F-links)connect SSPs directly.,SS7 Link Types,43,SS7 Protocol Stack,44,Message Transfer Part(MTP)consists of three levels corresponding to the OSI physical layer,data link layer,and network layer,resp
44、ectively.The MTP level 1(MTP1)defines the physical,electrical,and functional characteristics of the signaling links connecting SS7 components.The MTP level 2(MTP2)provides reliable transfer of signaling messages between two directly connected signaling points.The MTP level 3(MTP3)provides the functi
45、ons and procedures related to message routing and network management.Signaling Connection Control Part(SCCP)provides additional functions such as Global Title Translation(GTT)to the MTP.,SS7 Protocol Stack:MTP&SCCP,45,Integrated Services Digital Network User Part(ISUP)establishes circuit-switched ne
46、twork connections(e.g.,for call setup).Transaction Capabilities Application Part(TCAP)provides the capability to exchange information between applications using non-circuit-related signaling.Operations,Maintenance,and Administration Part(OMAP)is a TCAP application for network management.Mobile Appli
47、cation Part is a TCAP application that supports mobile roaming management.,SS7 Protocol:ISUP,TCAP,MAP,46,IETF Signaling Transport(SIGTRAN)working group addresses the issues regarding the transport of packet-based SS7 signaling over IP networks.SIGTRAN defines not only the architecture but also a sui
48、te of protocols,including the SCTP and a set of user adaptation layers(e.g.M3UA),which provides the same services of the lower layers of the traditional SS7.Why not TCP?TCP provides strict order-of-transmission which causes head-of-line blocking problem.The TCP socket does not support multi-homing.T
49、CP is vulnerable to blind Denial-of-Service(DoS)attacks such as flooding SYN attacks.,Stream Control Transmission Protocol(SCTP),47,Like TCPTo provide reliable IP connection.To employ TCP-friendly congestion control(including slow-start,congestion avoidance,and fast retransmit)Unlike TCPTo provide m
50、essage-oriented data delivery service and new delivery options(ordered or unordered)To provide selective acknowledgments for packet loss recoveryTo use a four-way handshake procedure to establish an association(i.e.,a connection).To offer new features that are particularly for SS7 signalingMulti-hom
