yuws 发表于 2012-6-29 10:24
看了 爱卫生发帖的时间，翻译+打字的速度比我单独看还要快。佩服
An intersystem change takes place when an MS changes between Iu mode and A/Gb mode of operation by the Routeing Area Update procedure or by PS handover. A prerequisite for an intersystem change is that the MS is GPRS-attached. The transition of the mobility management states is as specified for the corresponding mobility management procedures.
There is no transition of the session management states at an intersystem change.
一个系统间改变是在以下场景中产生，MS发生了Iu模式到A/Gb模式操作的改变，并且是由一个RAU流程或PS handover流程所触发的。一个系统间改变的前提条件是MS已经GPRS附着了。移动性管理的状态转变由相应的移动性管理流程来指明。
在系统间改变的流程中，不会发生会话管理状态的转变。
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Figure 52: Iu mode to A/Gb mode Intra SGSN Change
NOTE: All steps in figure 52 are common for architecture variants using Gn/Gp based interaction with a GGSN and using S4 based interactions with an S GW and P GW. For S4 based interaction with an S GW and P GW, procedure step (A) is defined in clause 6.13.1.1.2.
注释：在图例52中的所有步骤对于使用Gn/Gp接口和GGSN交互，还是使用S4接口和SGW/PGW交互的架构的都是公共的。基于S4接口和SGW/PGW的交互的步骤A，参考章节6.13.1.1.2。
1) The MS or RAN decides to perform an intersystem change which makes the MS switch to a new cell where A/Gb mode has to be used, and stops transmission to the network.
2) The MS sends a Routeing Area Update Request (old RAI, old P TMSI Signature, Update Type, Voice domain preference and UE's usage setting) message to the 2G+3G SGSN. Update Type shall indicate RA update or combined RA / LA-update or, if the MS wants to perform an IMSI attach, combined RA / LA update with IMSI attached requested. The BSS shall add the Cell Global Identity including the RAC and LAC of the cell where the message was received before passing the message to the 2G+3G SGSN. The UE sets the voice domain preference and UE's usage setting according to its configuration, as described in clause 5.3.15.
If there is an ongoing emergency bearer service and a Routing Area Update Request is received the Routing Area Update shall be rejected with a cause code indicating that access to GERAN is not allowed.
1）MS或RAN决定执行一个系统间改变，使得MS能切换到一个新的A/Gb模式下的小区，并且停止传递数据到网络。
2）MS发送RAU请求（old RAI、old P-TMSI签名、更新类型、语音域优先级和UE的使用设置）消息给2G+3G SGSN。更新类型应指明这个一个RAU或是一个联合的RA/LAY或者，如果MS想执行一个IMSI的附着、带有IMSI附着请求的联合的RA/LAU。BSS应加入CGI（小区全球标识）并包括小区的RAC和LAC到这个接收的消息中，然后再传递给2G+3G SGSN。UE根据它自己的配置，按照章节5.3.15的描述，来设置语音域优先级和它的使用设置。
3) If the MS is PMM CONNECTED state, the 2G+3G SGSN sends an SRNS Context Request (IMSI) message to the SRNS.
4) Upon reception of the SRNS Context Request message, the SRNS starts buffering and stops sending downlink PDUs to the MS. The SRNS responds with an SRNS Context Response (GTP SNDs, GTP SNUs, PDCP-SNDs, PDCP SNUs) message. The GTP sequence numbers are included for each PDP context indicating the next in-sequence downlink GTP-PDU to be sent to the MS and the next in-sequence GTP PDU to be tunnelled to the GGSN. For each active PDP context, which uses lossless PDCP, the SRNS also includes the uplink PDCP sequence number (PDCP SNU) and the downlink PDCP sequence number (PDCP-SND). PDCP SNU is the PDCP sequence number for the next expected in-sequence uplink packet to be received from the MS. PDCP-SND is the PDCP sequence number for the first downlink packet for which successful transmission has not been confirmed. The 2G+3G SGSN shall strip off the eight most significant bits of the passed PDCP sequence numbers, thus converting them to SNDCP N PDU numbers of the respective 2G GPRS PDP contexts.
3）如果MS是在PMM-CONNECTED状态，2G+3G SGSN发送SRNS Context Request(IMSI)消息给SRNS。
4)一旦接收到SRNS Context Request消息,SRNS开始缓存并且停止发送下行PDU给MS。SRNS响应一个SRNS Context Response(GTP SNDs、GTP SNUs、PDCP-SNDs、PDCP SNUs）消息。每个PDP上下文都包含了GTP序列号来指示序列中将要发送给MS的下一个下行GTP-PDU，以及序列中下一个将要发送给GGSN被封装进隧道的GTP PDU。对每一个active的PDP上下文，如使用了无损PDCP，SRNS也应包含上行的PDCP序列号(PDCP SNU即Sequence Number Uplink)以及下行PDCP序列号(PDCP-SND即Sequence Number Downlink)。PDCP SNU是一个PDCP序列号，表示的是下一个期望的从MS接收的有序的上行数据报文。PDCP-SND是一个PDCP序列号，表示的是第一个成功传递但还没有被确认的下行数据包。2G+3G SGSN应提取已经传递的PDCP序列号的八位最高有效位，将之转换为在2G GPRS PDP上下文中相应的SNDCP N PDU的值。
5) Security functions may be executed.
5）安全功能可以被执行。
6) If the MS is PMM CONNECTED, the 2G+3G SGSN sends an SRNS Data Forward Command (RAB ID, Transport Layer Address, Iu Transport Association) message to the SRNS. This informs the SRNS that the 2G+3G SGSN is ready to receive data packets. Upon reception of SRNS Data Forward Command message from the 2G+3G SGSN the SRNS shall start the data-forwarding timer.
6a)If Direct Tunnel was established in Iu mode the SGSN sends Update PDP Context Request to the GGSN(s) concerned to establish the GTP tunnel between SGSN and GGSN. The GGSN(s) update the address for User Plane and downlink TEID for data and return an Update PDP Context Response. Otherwise, if there were changes of for example the RAT type that e.g. can be used for charging, the SGSN sends Update PDP Context Request (SGSN Address and TEID, QoS Negotiated, RAT type) message to the GGSN.
6)如果MS是PMM-CONNECTED状态，2G+3G SGSN发送SRNS Data Forward Command(RAB ID,传输层地址、Iu传输关联）消息给SRNS。这将通知SRNS，2G+3G SGSN已经准备好接收数据报文。一旦从2G+3G SGSN接收到这个消息，SRNS应开始启动数据转发计时器。
6a）如果在Iu模式建立了直接隧道，SGSN发送Update PDP Context Request给关联的GGSN，来建立在SGSN和GGSN之间的GTP隧道。GGSN更新用户面地址和下行数据的TEID并返回Update PDP Context Response消息。除此以外，如果有别的变化，如RAT类型的变化需要用于计费目的，SGSN发送Update PDP Context Request(SGSN地址和TEID、协商的QOS、RAT类型）消息给GGSN。
7) For each RAB indicated by the SRNS Data Forward Command the SRNS starts duplicating and tunnelling the buffered GTP-PDUs back to the 2G+3G SGSN. For each radio bearer which uses lossless PDCP the GTP-PDUs related to transmitted but not yet acknowledged PDCP PDUs are duplicated and tunnelled back to the 2G+3G SGSN together with their related downlink PDCP sequence numbers. The 2G+3G SGSN converts the PDCP sequence numbers to SNDCP sequence number (by stripping off the eight most significant bits of the PDCP sequence numbers).
7）由SRNS Data Forward Command指明的每一个RAB，SRNS开始将缓存的GTP-PDU复制并且封入隧道发给2G+3G SGSN。对使用了无损PDCP压缩的每一个无线承载，相关的已经传输但还没有得到确认的GTP-PDU，PDCP PDU将被复制并且和他们相关联的PDCP序列号一起通过隧道回传给2G+3G SGSN。2G+3G SGSN将把PDCP序列号转换为SNDCP序列号(通过去除PDCP序列号的最高8位）。
8) The 2G+3G SGSN sends an Iu Release Command message to the SRNS. When the RNC data-forwarding timer has expired, the SRNS responds with an Iu Release Complete message.
8）2G+3G SGSN发送Iu Release Command消息给SRNS。当RNC转发数据计时器超时，SRNS响应一个Iu Release Complete消息。
9) If the association has to be established i.e. if Update Type indicates combined RA / LA update with IMSI attach requested, or if the LA changed with the routeing area update, then the 2G+3G SGSN sends a Location Update Request (new LAI, IMSI, SGSN Number, Location Update Type) to the VLR. Location Update Type shall indicate IMSI attach if Update Type in step 1 indicated combined RA / LA update with IMSI attach requested. Otherwise, Location Update Type shall indicate normal location update. When the SGSN does not provide functionality for the Intra Domain Connection of RAN Nodes to Multiple CN Nodes, the VLR number is derived from the RAI. When the SGSN provides functionality for Intra Domain Connection of RAN Nodes to Multiple CN Nodes, the SGSN uses the RAI and a hash value from the IMSI to determine the VLR number. The VLR creates or updates the association with the 2G+3G SGSN by storing the SGSN Number.
9）如果关联需要建立，也就是更新类型指示了带有IMSI附着的联合的RA/LAU请求，或在RAU时发生了LA的变化，那么2G+3G SGSN发送Location Update Request(新LAI、IMSI、SGSN编号、Location Update Type)给VLR。Location Update Type应指示为IMSI附着---如果在步骤1的更新类型指示的是带有IMSI附着请求的联合RA/LAU。除此以外，Location Update Type应指示为一个正常的Location Update。当SGSN不为多个CN节点提供到RAN节点的域内连接功能的话，VLR编号将从RAI获取。当SGSN提供这个功能时，SGSN使用RAI以及从IMSI得到的一个哈希函数来决定VLR编号。VLR通过存储SGSN编号来创建或更新与2G+3G SGSN的关联。
In this case, clause 6.13.1.1.1 applies except for steps 6a and 7, as well as section specific general statements stated below.
在本例中，章节6.13.1.1.1中的流程步骤除了6a和第7步，都适用于本例。因此不再列出，以下至列出不同部分。
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Figure 52-2: step 6a for Iu mode to A/Gb mode Intra SGSN Change using S4
NOTE: Steps a) and d) are common for architecture variants with GTP-based S5/S8 and PMIP-based S5/S8. For a PMIP-based S5/S8, procedure step (A1) is defined in TS 23.402 [90]. Steps b) and c) in Figure 52-2 concern GTP-based S5/S8.
注释：步骤a和d对于使用基于GTP或PMIP的S5/S8接口来说都是公共的。对于基于PMIP的S5/S8，步骤A1在TS23.402描述。步骤b和c在图例52-2中是基于GTP的S5/S8.
a) In this procedure flow the Serving GW is not relocated. If Direct Tunnel was established in Iu mode or if there were changes of for example the RAT type that e.g. can be used for charging, the SGSN sends Modify Bearer Request (SGSN Address and TEID, serving network identity, RAT type) message to the Serving GW.
b) The Serving GW informs the P GW(s) about the change of for example the RAT type that e.g. can be used for charging, by sending the message Modify Bearer Request (Serving GW Address and TEID, RAT type) to the concerned P GW(s). If dynamic PCC is deployed, and RAT type information needs to be conveyed from the P GW to the PCRF, then the P GW sends RAT type information to the PCRF as defined in TS 23.203 [88].
c) Each P GW updates its context field and returns a Modify Bearer Response (MSISDN, P GW address and TEID) message to the Serving GW. MSISDN is included if available in the stored UE context.
a)在这个流程中,SGW没有被重新选择。如果直接隧道在Iu模式建立或有一些变化例如RAT类型变化可以被用于计费的，SGSN发送Modify Bearer Request（SGSN地址和TEID,服务网络ID，RAT类型）消息给SGW。
b）SGW通知PGW这个可用于计费目的的变化，例如RAT类型的变化，通过发送Modify Bearer Request（SGW地址和TEID、RAT类型）消息给相关的PGW来告知。如果部署了动态的PCC，并且RAT类型信息需要从PGW传递给PCRF，那PGW将发送RAT类型信息给PCRF，这在TS23.203中定义。
c）每个PGW更新它的上下文字段并且返回Modify Bearer Response（MSISDN、PGW地址和TEID)消息给SGW。MSISDN如果在存储的UE上下文中有的话也将被包含。
d) The Serving GW updates the address for User Plane and downlink TEID for data and return a Modify Bearer Response (Serving GW address and TEID, P GW address and TEIDs (for GTP based S5/S8) or GRE keys (for PMIP based S5/S8) at the PDN GW(s) for uplink traffic) message.
e) In case Direct Tunnel in Iu mode was not established, for each RAB indicated by the SRNS Data Forward Command the SRNS starts duplicating and tunnelling the buffered GTP-PDUs back to the 2G+3G SGSN. For each radio bearer which uses lossless PDCP the GTP-PDUs related to transmitted but not yet acknowledged PDCP PDUs are duplicated and tunnelled back to the 2G+3G SGSN together with their related downlink PDCP sequence numbers. The 2G+3G SGSN converts the PDCP sequence numbers to SNDCP sequence number (by stripping off the eight most significant bits of the PDCP sequence numbers).
In case Direct Tunnel in Iu mode was established, the packets are forwarded via the S GW.
d）SGW更新用户面地址和数据的下行TEID并返回一个Modify Bearer Response(SGW地址和TEID，在PGW上用于上行流量的PGW地址和TEID(基于GTP的S5/S8)或GRE密钥（基于PMIP的S5/S8)）消息给SGSN。
e）如果Iu模式的直接隧道没有建立，对每个在SRNS Data Forward Command中指明的RAB，SRNS开始将缓存的GTP-PDU进行复制并且通过隧道返回给2G+3G SGSN。对使用了无损PDCP压缩的每一个无线承载，相关的已经传输但还没有得到确认的GTP-PDU，PDCP PDU将被复制并且和他们相关联的PDCP序列号一起通过隧道回传给2G+3G SGSN。2G+3G SGSN将把PDCP序列号转换为SNDCP序列号(通过去除PDCP序列号的最高8位）。
如果Iu模式的直接隧道建立，数据包将通过SGW被转发。
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Figure 53: A/Gb mode to Iu mode Intra SGSN Change
1) The MS or the RAN decides to perform an intersystem change which makes the MS switch to a new cell where Iu mode has to be used, and stops transmission to the network.
2) The MS initiates an RRC connection establishment and sends a Routeing Area Update Request (P TMSI, Old RA, Old P TMSI Signature, Update Type, CM, Voice domain preference and UE's usage setting) message to the combined 2G+3G SGSN. Update Type shall indicate RA update or combined RA / LA update or, if the MS wants to perform an IMSI attach, combined RA / LA update with IMSI attach requested and also if the MS has a follow on request, i.e. if there is pending uplink traffic (signalling or data). The SGSN may use, as an implementation option, the follow-on request indication to release or keep the Iu connection after the completion of the RA update procedure. The SRNS shall add an identifier of the area where the message was received before passing the message to the 2G+3G SGSN. The 2G+3G SGSN stops transmission of N PDUs to the MS. The UE sets the voice domain preference and UE's usage setting according to its configuration, as described in clause 5.3.15.
1)MS或RAN决定执行系统间改变，使得MS切换到一个Iu模式的新小区，并停止传输数据到网络侧。
2）MS发起RRC连接建立以及发送RAU Request(P-TMSI、old RA、old P-TMSI签名、更新类型、CM、语音域优先级和UE的使用设置）消息给联合的2G+3G SGSN。更新类型应指明这是一个RAU还是一个联合的RA/LAU，或者，如果MS想执行一个IMSI的附着、带有IMSI附着请求的联合的RA/LAU，并且呢MS还带上了follow on request这个flag来指示有一个pending的上行流量（信令或数据）。SGSN可以使用，做为一个实现的选项，这个follow on request的指示可以用于决定在完成RAU流程之后是否保持或释放Iu连接。SRNS应在收到的消息中加上区域ID，然后再传送给2G+3G SGSN。2G+3G SGSN停止到MS的N-PDU的传输。UE根据它自己的配置，按照章节5.3.15的描述，来设置语音域优先级和它的使用设置。
3) Security functions may be executed.[attach]253[/attach]
Figure 53-2: step 11 for A/Gb mode to Iu mode Intra-SGSN Change using S4
NOTE: Steps a) and d) are common for architecture variants with GTP-based S5/S8 and PMIP-based S5/S8. For a PMIP-based S5/S8, procedure step (A1) is defined in TS 23.402 [90]. Steps b) and c) in Figure 53-2 concern GTP-based S5/S8.
注释：步骤a和d对于使用基于GTP或PMIP的S5/S8接口来说都是公共的。对于基于PMIP的S5/S8，步骤A1在TS23.402描述。步骤b和c在图例53-2中是基于GTP的S5/S8.
a) If the SGSN established Direct Tunnel it shall send Modify Bearer Request (RNC Address and TEID, serving network identity, RAT type) message to the Serving GW and include the RNC's Address for User Plane, downlink TEID for data and DTI to instruct the Serving GW to apply Direct Tunnel specific error handling as described in clause 13.8. Otherwise, if there were changes of for example the RAT type that e.g. can be used for charging, the SGSN shall send Modify Bearer Request (SGSN Address and TEID, serving network identity, RAT type) message to the Serving GW and include the SGSN's Address for User Plane, downlink TEID for data.
a)如果直接隧道建立，SGSN发送Modify Bearer Request（RNC地址和TEID,服务网络ID，RAT类型）消息给SGW并且包含了RNC用户面地址、下行数据的TEID和DTI来指示SGW要应用直接隧道，错误处理流程在13.8章节描述。除此以外，如果有一些变化例如RAT类型变化可以被用于计费的，SGSN发送Modify Bearer Request（SGSN地址和TEID,服务网络ID，RAT类型）消息给SGW并且应包含用户数据的下行TEID和用户面SGSN地址。
b) The Serving GW informs the P GW(s) about the change of for example the RAT type that e.g. can be used for charging, by sending the message Modify Bearer Request (Serving GW Address and TEID, RAT type) to the concerned P GW(s). If dynamic PCC is deployed, and RAT type information needs to be conveyed from the P GW to the PCRF, then the P GW sends RAT type information to the PCRF as defined in TS 23.203 [88].
b)SGW通知PGW这个可用于计费目的的变化，例如RAT类型的变化，通过发送Modify Bearer Request（SGW地址和TEID、RAT类型）消息给相关的PGW来告知。如果部署了动态的PCC，并且RAT类型信息需要从PGW传递给PCRF，那PGW将发送RAT类型信息给PCRF，这在TS23.203中定义。
c) Each P GW updates its context field and returns a Modify Bearer Response (MSISDN, P GW address and TEID) message to the Serving GW. MSISDN is included if available in the stored UE context.
c）每个PGW更新它的上下文字段并且返回Modify Bearer Response（MSISDN、PGW地址和TEID)消息给SGW。MSISDN如果在存储的UE上下文中有的话也将被包含。
d) The Serving GW updates the Address for User Plane and TEID for downlink data and return a Modify Bearer Response (Serving GW address and TEID, P GW address and TEIDs (for GTP-based S5/S8) or GRE keys (for PMIP-based S5/S8) at the PDN GW(s) for uplink traffic) message.
d）SGW更新用户面地址和数据的下行TEID并返回一个Modify Bearer Response(SGW地址和TEID，在PGW上用于上行流量的PGW地址和TEID(基于GTP的S5/S8)或GRE密钥（基于PMIP的S5/S8)）消息给SGSN。
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Figure 54: Iu mode to A/Gb mode Inter-SGSN Change
1) The MS or RAN decides to perform an inter-system change, which makes the MS switch to a new cell where A/Gb mode has to be used, and stops transmission to the network.
1）MS或RAN决定执行一个系统间改变，使得MS能切换到一个新的A/Gb模式下的小区，并且停止传递数据到网络。
2) The MS sends a Routeing Area Update Request (old RAI, old P TMSI Signature, Update Type, MS Network Capability, Voice domain preference and UE's usage setting) message to the new 2G SGSN. Update Type shall indicate RA update or combined RA / LA update, or, if the MS wants to perform an IMSI attach, combined RA / LA update with IMSI attach requested. The BSS shall add the Cell Global Identity including the RAC and LAC of the cell where the message was received before passing the message to the new 2G SGSN. The UE sets the voice domain preference and UE's usage setting according to its configuration, as described in clause 5.3.15.
If there is an ongoing emergency bearer service and a Routing Area Update Request is received the Routing Area Update shall be rejected with a cause code indicating that access to GERAN is not allowed.
2）MS发送RAU请求（old RAI、old P-TMSI签名、更新类型、MS网络能力、语音域优先级和UE的使用设置）消息给new 2G+3G SGSN。更新类型应指明这个一个RAU或是一个联合的RA/LAU或者，如果MS想执行一个IMSI的附着、带有IMSI附着请求的联合的RA/LAU。BSS应加入CGI（小区全球标识）并包括小区的RAC和LAC到这个接收的消息中，然后再传递给2G+3G SGSN。UE根据它自己的配置，按照章节5.3.15的描述，来设置语音域优先级和它的使用设置。
如果有一个正在进行的紧急承载服务，并且在此种情况下执行了RAU，那网络侧应返回RAU reject，并带上原因值为"GERAN不允许".
3) The new 2G SGSN sends an SGSN Context Request (old RAI, TLLI, old P TMSI Signature, New SGSN Address) message to the old 3G SGSN to get the MM and PDP contexts for the MS. If the new SGSN provides functionality for Intra Domain Connection of RAN Nodes to Multiple CN Nodes, the new SGSN may derive the old SGSN from the old RAI and the old P-TMSI (or TLLI) and send the SGSN Context Request message to this old SGSN. Otherwise, the new SGSN derives the old SGSN from the old RAI. In any case the new SGSN will derive an SGSN that it believes is the old SGSN. This derived SGSN is itself the old SGSN, or it is associated with the same pool area as the actual old SGSN and it will determine the correct old SGSN from the P-TMSI (or TLLI) and relay the message to that actual old SGSN. The old 3G-SGSN validates the old P TMSI Signature and responds with an appropriate error cause if it does not match the value stored in the old 3G SGSN. If the received old P-TMSI Signature does not match the stored value, the security functions in the new 2G-SGSN should be initiated. If the security functions authenticate the MS correctly, the new 2G-SGSN shall send an SGSN Context Request (old RAI, TLLI, MS Validated, New SGSN Address) message to the old 3G-SGSN. MS Validated indicates that the new 2G-SGSN has authenticated the MS. If the old P TMSI Signature was valid or if the new 2G-SGSN indicates that it has authenticated the MS correctly, the old 3G SGSN starts a timer. If the MS is not known in the old 3G SGSN, the old 3G SGSN responds with an appropriate error cause.
3)new 2G SGSN发送一个SGSN Context Request(old RAI、TLLI、old P-TMSI签名、新SGSN地址）消息给old 3G SGSN来获取MS的MM和PDP上下文。如果new SGSN提供为多个CN节点提供到RAN节点的域内连接功能时，new SGSN可以根据old RAI以及old P-TMSI（或TLLI)来得到old SGSN的地址并发送SGSN Context Request消息给这个old SGSN。否则，new SGSN将从old RAI获取到old SGSN的地址。在任何的场景中，new SGSN都将获取一个SGSN并相信这就是old SGSN。而实际上，这个获取到的SGSN可能真的自己就是old SGSN，也可能只是关联到一个SGSN POOL区域的一个缺省SGSN，那这个获取到的SGSN将从P-TMSI（或TLLI)来得到正确的old SGSN并将消息传递给这个实际的old SGSN（但这个过程对new 2G SGSN来说是透明的）。old 3G-SGSN验证P-TMSI签名，如果签名和存储在它内部的签名值不匹配，那old 3G SGSN将响应一个合适的错误代码。如果收到的old P-TMSI签名和SGSN存储的签名不匹配，那将在new 2G-SGSN内触发一个安全功能（鉴权）的执行。如果安全功能能对MS正确鉴权，那new 2G-SGSN应发送一个SGSN Context Request（old RAI、TLLI、MS已验证、new SGSN地址）消息再给这个old 3G-SGSN。MS已验证代表new 2G-SGSN已经对MS做了鉴权。而如果old P-TMSI签名是正确的或者new 2G-SGSN指示已经对MS进行了正确的鉴权，old 3G SGSN将启动一个计时器。如果MS在old 3G SGSN内未知，那old 3G SGSN将响应一个合适的错误代码。
4) If the MS is PMM CONNECTED the old 3G SGSN sends an SRNS Context Request (IMSI) message to the SRNS. Upon receipt of this message the SRNS buffers and stops sending downlink PDUs to the MS and returns an SRNS Context Response (GTP SNDs, GTP SNUs, PDCP-SNDs, PDCP SNUs) message. The SRNS shall include for each PDP context the next in-sequence GTP sequence number to be sent to the MS and the GTP sequence number of the next uplink PDU to be tunnelled to the GGSN. For each active PDP context, which uses lossless PDCP, the SRNS also includes the uplink PDCP sequence number (PDCP SNU) downlink PDCP sequence number (PDCP-SND). PDCP SNU shall be the next in-sequence PDCP sequence number expected from the MS. PDCP-SND is the PDCP sequence number for the first downlink packet for which successful transmission has not been confirmed. The 3G SGSN shall strip off the eight most significant bits of the passed PDCP sequence numbers, thus converting them to SNDCP N PDU numbers and stores the N-PDU numbers in its PDP contexts.
4)如果MS是PMM-CONNECTED状态的，那old 3G SGSN将发送SRNS Context Request（IMSI）消息给SRNS。一旦接收到这个消息，SRNS将缓存并且停止发送下行PDU给MS，并且返回一个SRNS Context Response(GTP SNDs、GTP SNUs、PDCP-SNDs、PDCP SNUs）消息。SRNS应对每个PDP上下文都包含下一个将要发送给MS的有序的GTP序列号，以及序列中下一个将要发送给GGSN被封装进隧道的上行 PDU。对每一个active的PDP上下文，如使用了无损PDCP，SRNS也应包含上行的PDCP序列号(PDCP SNU即Sequence Number Uplink)以及下行PDCP序列号(PDCP-SND即Sequence Number Downlink)。PDCP SNU是一个PDCP序列号，表示的是下一个期望的从MS接收的有序的上行数据报文。PDCP-SND是一个PDCP序列号，表示的是第一个成功传递但还没有被确认的下行数据包。3G SGSN应提取已经传递的PDCP序列号的八位最高有效位，将之转换为在2G GPRS PDP上下文中相应的SNDCP N PDU的值，并将N-PDU值存储到它的PDP上下文中。
[attach]277[/attach]
Figure 54-2: steps 3, 5, 7, 9 for Iu mode to A/Gb mode Inter-SGSN Change using S4
Steps 3, 5 and 7 are identical to the Gn/Gp case in clause 6.13.2.2.1, except that:
- Message SGSN Context Request is replaced by message Context Request;
- Parameter PDP Contexts is replaced by parameter EPS Bearer Contexts.
MM Context and EPS Bearer Context when used at the S16 interface are defined by clause 13.2.2. For RAU between two S4-SGSNs, the old SGSN shall include the APN Restriction, CGI/SAI/RAI change support indication and Change Reporting Action in the Context Response message.
步骤3，5，7和6.13.2.2.1中的基于Gn/Gp的例子是相同的，区别在于：
-- 消息SGSN Context Request被Context Request消息替代；
-- 参数PDP Context被参数EPS Bearer Context替代。
在使用S16接口时的MM上下文和EPS承载上下文在13.2.2章定义。对于两个S4-SGSN之间的RAU，old SGSN应在Context Response消息中包含APN Restriction,CGI/SAI/RAI变更支持指示和变更报告指示。
9) In case Direct Tunnel in Iu mode was not established, the old 3G SGSN tunnels the GTP PDUs to the new 2G SGSN. For GTPv2 or GTPv1 user plane, the conversion of PDCP sequence numbers to SNDCP sequence numbers (the eight most significant bits shall be stripped off) shall be done in the new SGSN. No N PDU sequence numbers shall be indicated for these N PDUs.
In case Direct Tunnel in Iu mode was established, the packets are forwarded via the S GW.
9）如果在Iu模式的直接隧道没有建立，则old 3G SGSN将GTP PDU通过隧道发给new 2G SGSN。对于GTPV2或GTPV1的用户平面，new SGSN应将PDCP序列号转换为SNDCP序列号（剥离最高八位有效位）。没有N-PDU序列号来指示这些N-PDU。
一旦在Iu模式建立了直接隧道，这些包将转发给SGW。
10）Box（B）
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Figure 54-3: step 10 for Iu mode to A/Gb mode Inter-SGSN Change using S4
NOTE: Steps a) and d) are common for architecture variants with GTP-based S5/S8 and PMIP-based S5/S8. For a PMIP-based S5/S8, procedure step (A1) is defined in TS 23.402 [90]. Steps b) and c) in Figure 54-3 concern GTP-based S5/S8.
注释：步骤a和d对于使用GTP或PMIP的S5/S8来说都是公共的。对于基于PMIP的S5/S8，步骤A1在TS23.402定义。步骤b和c和基于GTP的S5/S8接口有关。
a) The new 2G SGSN sends a Modify Bearer Request (new SGSN Address, TEID, serving network identity, CGI/SAI, User CSG Information, RAT type, MS Info Change Reporting support indication) message to the Serving GW. The SGSN shall send the serving network identity to the Serving GW.
b) The Serving GW informs the P GW(s) about the change of Serving GW Address and TEID, as well as about RAT type that e.g. can be used for charging, by sending the message Modify Bearer Request (Serving GW Address and TEID, RAT type) to the concerned P GW(s). If dynamic PCC is deployed, and RAT type information needs to be conveyed from the P GW to the PCRF, then the P GW shall send RAT type information to the PCRF as defined in TS 23.203 [88].
a)new 2G SGSN发送Modify Bearer Request(new SGSN地址、TEID、服务网络ID、CGI/SAI、用户CSG信息、RAT类型、MS信息变化报告支持指示）消息给SGW。SGSN应发送服务网络ID给SGW。
b）SGW通过发送Modify Bearer Request消息来通知PGW关于SGW地址和TEID的变化，以及RAT类型（例如可用于计费目的）。如果部署了动态PCC，则RAT类型信息将需要由PGW传递给PCRF，然后PGW应将RAT类型信息发送给在规范TS23.203中定义的PCRF。
c) Each P GW updates its context fields and returns a Modify Bearer Response (MSISDN, P GW address and TEID, Prohibit Payload Compression, MS Info Change Reporting Action, CSG Information Reporting Action) message. The Prohibit Payload Compression indicates that the SGSN should negotiate no data compression for this EPS Bearer context. MSISDN is included if available in the stored UE context.
d) The Serving GW updates the Address for User Plane and TEID for downlink data and return a Modify Bearer Response (Serving GW address and TEID, P GW address and TEIDs (for GTP based S5/S8) or GRE keys (for PMIP based S5/S8) at the PDN GW(s) for uplink traffic, CSG Information Reporting Action) message.
c)每个PGW更新它的上下文字段并返回Modify Bearer Response (MSISDN、PGW地址和TEID、禁止payload压缩、MS信息变化报告行动、CSG信息报告行动）消息。禁止payload压缩指示SGSN不应为这个EPS承载上下文来协商数据压缩。MSISDN如果在存储的UE上下文中有的话也应提供。
d) SGW更新下行数据的用户平面地址和TEID并返回一个Modify Bearer Response (SGW地址和TEID、PGW上用于上行流量的PGW地址和TEID（基于GTP的S5/S8）或GRE密钥（基于PMIP的S5/S8)，CSG信息报告行动）消息。
If the new SGSN is unable to update the Bearer context in the S GW or in one or more P GW(s), the new SGSN shall deactivate the corresponding Bearer contexts as described in clause "SGSN initiated PDP Context Deactivation Procedure". This shall not cause the SGSN to reject the routeing area update.
The Bearer Contexts shall be sent from old to new SGSN in a prioritized order, i.e. the most important Bearer Context first in the Context Response message. (The prioritization method is implementation dependent, but should be based on the current activity).
The new SGSN shall determine the Maximum APN restriction based on the received APN Restriction of each Bearer context from the P GW(s) or old S4-SGSN and then store the new Maximum APN restriction value.
The bearer contexts shall be prioritized by the new SGSN. If the new SGSN is unable to support the same number of active Bearer contexts as received from old SGSN, the new SGSN should use the prioritisation when deciding which Bearer contexts to maintain active and which ones to delete. In any case, the new SGSN shall first update all contexts in the S GW and in one or more P GW(s) and then deactivate the context(s) that it cannot maintain as described in clause "SGSN initiated PDP Context Deactivation Procedure". This shall not cause the SGSN to reject the routeing area update.
如果new SGSN不能更新在SGW或一个或多个PGW中的承载上下文，那new SGSN应将相应的承载上下文去激活，如章节“initiated PDP Context Deactivation Procedure”描述的那样。这不应导致SGSN拒绝RAU。
Bearer Contexts应按照优先级顺序从old传送到new SGSN，也就是最重要的Bearer Context优先出现在Context Response消息中。（优先级的方法取决于具体的实现，但应基于当前的事件给出。）
New SGSN应根据从PGW或old S4-SGSN接收到的每个承载上下文的APN限制，来决定最大的APN限制，并且存储这个新的最大APN限制的值。
Bearer Contexts应在new SGSN中按照优先级顺序排序。如果new SGSN不能支持从old SGSN来的相同数量的active承载上下文，那new SGSN应根据优先级来决定哪些承载上下文应该保持或被删除。在任何场景下，new SGSN应首先在SGW和一个或多个PGW中更新所有的上下文，然后将不能保持的上下文按照章节“SGSN initiated PDP Context Deactivation Procedure”的描述来去激活。这不应导致SGSN拒绝RAU。
[attach]279[/attach]
Figure 55: A/Gb mode to Iu mode Inter SGSN Change
1) The MS or RAN decides to perform an inter-system change, which makes the MS switch to a new cell where Iu mode has to be used, and stops transmission to the network.
1)MS或RAN决定执行inter-system change，使得MS切换到一个新小区并使用Iu模式，并停止到网络侧的数据传输。
2) The MS sends a Routeing Area Update Request (P TMSI, old RAI, old P TMSI Signature, Update Type, CM, MS Network Capability, Voice domain preference and UE's usage setting) message to the new 3G SGSN. Update Type shall indicate RA update or combined RA / LA update, or, if the MS wants to perform an IMSI attach, combined RA / LA update with IMSI attach requested, and also if the MS has a follow-on request, i.e. if there is pending uplink traffic (signalling or data). The SGSN may use, as an implementation option, the follow-on request indication to release or keep the Iu connection after the completion of the RA update procedure. The SRNC shall add the Routeing Area Identity before forwarding the message to the 3G SGSN. This RA identity corresponds to the RAI in the MM system information sent by the SRNC to the MS. The UE sets the voice domain preference and UE's usage setting according to its configuration, as described in clause 5.3.15.
2)MS发送RAU请求（P-TMSI、old RAI、old P-TMSI签名、更新类型、CM、MS网络侧能力、语音域优先级以及UE的使用设置）消息给new 3G SGSN。更新类型指明这是个一个RAU或是一个联合的RA/LAU或者，如果MS想执行一个IMSI的附着、带有IMSI附着请求的联合的RA/LAU，并且如果MS有一个后续的请求，也就是如果它有处于pending状态的上行流量（信令或数据）。SGSN可以使用，作为一个实现的可选项，使用follow-on request指示来决定在RAU流程完成之后是否释放或保持Iu连接。SRNC应加入RAI然后再传递给3G SGSN。RA标识对应到从SRNC发送给MS的MM系统新中的RAI。UE根据它自己的配置，按照章节5.3.15的描述，来设置语音域优先级和它的使用设置。
3) The new 3G SGSN uses the old RAI received from the MS to derive the old 2G SGSN address, and sends an SGSN Context Request (old RAI, old P TMSI, New SGSN Address) message to the old 2G SGSN to get the MM and PDP contexts for the MS. If the new SGSN provides functionality for Intra Domain Connection of RAN Nodes to Multiple CN Nodes, the new SGSN may derive the old SGSN from the old RAI and the old P-TMSI and send the SGSN Context Request message to this old SGSN. Otherwise, the new SGSN derives the old SGSN from the old RAI. In any case the new SGSN will derive an SGSN that it believes is the old SGSN. This derived SGSN is itself the old SGSN, or it is associated with the same pool area as the actual old SGSN and it will determine the correct old SGSN from the P-TMSI and relay the message to that actual old SGSN. The old 2G-SGSN validates the old P TMSI Signature and responds with an appropriate error cause if it does not match the value stored in the old 2G SGSN. If the received old P-TMSI Signature does not match the stored value, the old 2G-SGSN should initiate the security functions in the new 3G-SGSN. If the security functions authenticate the MS correctly, the new 3G-SGSN shall send an SGSN Context Request (old RAI, IMSI, MS Validated, New SGSN Address) message to the old 2G-SGSN. MS Validated indicates that the new 3G-SGSN has authenticated the MS. If the old P TMSI Signature was valid or if the new 3G-SGSN indicates that it has authenticated the MS correctly, the old 2G SGSN starts a timer and stops the transmission of N PDUs to the MS.
3)new 3G SGSN使用从MS收到的old RAI来得到old 2G SGSN地址，发送一个SGSN Context Request(old RAI、old P-TMSI、新SGSN地址）消息给old 2G SGSN来获取MS的MM和PDP上下文。如果new SGSN提供为多个CN节点提供到RAN节点的域内连接功能时，new SGSN可以根据old RAI以及old P-TMSI来得到old SGSN的地址并发送SGSN Context Request消息给这个old SGSN。否则，new SGSN将从old RAI获取到old SGSN的地址。在任何的场景中，new SGSN都将获取一个SGSN并相信这就是old SGSN。而实际上，这个获取到的SGSN可能真的自己就是old SGSN，也可能只是关联到一个SGSN POOL区域的一个缺省SGSN，那这个获取到的SGSN将从P-TMSI来得到正确的old SGSN并将消息传递给这个实际的old SGSN。old 2G-SGSN验证old P-TMSI签名，如果签名和存储在它内部的签名值不匹配，那old 2G SGSN将响应一个合适的错误代码。如果收到的old P-TMSI签名和SGSN存储的签名不匹配，那将在new 3G-SGSN内触发一个安全功能（鉴权）的执行。如果安全功能能对MS正确鉴权，那new 3G-SGSN应发送一个SGSN Context Request（old RAI、IMSI、MS已验证、new SGSN地址）消息再给这个old 2G-SGSN。MS已验证代表new 3G-SGSN已经对MS做了鉴权。而如果old P-TMSI签名是正确的或者new 3G-SGSN指示已经对MS进行了正确的鉴权，old 2G SGSN将启动一个计时器并且停止传送N-PDU给MS。
4) The old 2G SGSN responds with an SGSN Context Response (MM Context, PDP Contexts, Negotiated Evolved ARP) message. Each PDP Context includes the GTP sequence number for the next downlink N PDU to be sent to the MS and the GTP sequence number for the next uplink N PDU to be tunnelled to the GGSN. Each PDP Context also includes the SNDCP Send N PDU Number for the next downlink N PDU to be sent in acknowledged mode SNDCP to the MS and the SNDCP Receive N PDU Number for the next uplink N PDU to be received in acknowledged mode SNDCP from the MS. The new 3G-SGSN derives the corresponding PDCP sequence numbers from these N PDU sequence numbers by adding eight most significant bits "1". These PDCP sequence numbers are stored in the 3G-SGSN PDP contexts. The new 3G-SGSN shall ignore the MS Network Capability contained in MM Context of SGSN Context Response only when it has previously received an MS Network Capability in the Routeing Area Request.
4)old 2G SGSN响应一个SGSN Context Response（MM上下文、PDP上下文、协商的演进ARP)消息。每个PDP上下文包括了下一个要发给MS的下行N-PDU的序列号以及下一个将被封进隧道送给GGSN的上行N-PDU的GTP序列号。每个PDP上下文也包含了下一个下行方向要通过确认模式SNDCP发送给MS的N-PDU的SNDCP Send N-PDU Number，以及下一个上行方向通过确认模式SNDCP从MS接收的上行N-PDU的SNDCP Receive N-PDU Number。New 3G-SGSN从这些N-PDU序列号中加上8个有效比特位1得到对应的PDCP序列号。这些PDCP序列号将存储在3G-SGSN PDP上下文中。New 3G-SGSN只有在之前从RA请求中收到了MS网络侧能力的时候，才可以忽略在SGSN Context Response消息中的MM Context里包含的MS网络侧能力。
5) Security functions may be executed. If the SGSN Context Response message did not include IMEISV and the ADD function is supported by the new 3G-SGSN, then the IMEISV shall be retrieved from the MS.
6) The new 3G SGSN sends an SGSN Context Acknowledge message to the old 2G SGSN. This informs the old 2G SGSN that the new 3G SGSN is ready to receive data packets belonging to the activated PDP contexts. The old SGSN marks in its context that the MSC/VLR association and the information in the GGSNs and the HLR are invalid. This triggers the MSC/VLR, the GGSNs, and the HLR to be updated if the MS initiates a routeing area update procedure back to the old SGSN before completing the ongoing routeing area update procedure.
5)安全功能可以执行。如果SGSN Context Response消息不包含IMEISV并且在new 3G-SGSN中支持ADD功能，那应从MS获取IMEISV。
6)New 3G-SGSN发送SGSN Context Acknowledge消息给old 2G-SGSN。这将通知old 2G-SGSN，new 3G-SGSN已经准备接收属于这个激活的PDP上下文的数据报文了。Old SGSN将它的上下文和MSC/VLR的关联以及这个上下文和GGSN以及HLR的相关信息标记为invalid。这样，在完成正在进行的RAU流程之前，如果MS又返回到old SGSN并发起一个RAU流程，将触发和MSC/VLR、GGSN以及HLR的更新操作。
7) The old 2G SGSN duplicates the buffered N PDUs and starts tunnelling them to the new 3G SGSN. Additional N PDUs received from the GGSN before the timer described in step 3 expires are also duplicated and tunnelled to the new 3G SGSN. N-PDUs that were already sent to the MS in acknowledged mode SNDCP and that are not yet acknowledged by the MS are tunnelled together with their related SNDCP N-PDU sequence number. No PDCP sequence numbers shall be indicated for these N-PDUs. No N PDUs shall be forwarded to the new 3G SGSN after expiry of the timer described in step 3.
7)Old 2G SGSN将缓存中的N-PDU复制并且开始通过隧道传递给new 3G SGSN。在步骤3的计时器超时之前从GGSN收到了额外的N-PDU，则也复制并通过隧道发送给new 3G-SGSN。那些由确认模式SNDCP已经发给MS的N-PDU但如果没有得到MS的确认的话，则将和他们相关的SNDCP N-DPU序列号一起隧道发送。没有PDCP序列号来指示这些N-PDU。在步骤3的计时器超时之后，将不再转发N-PDU给new 3G-SGSN。
8) The new 3G SGSN sends an Update PDP Context Request (new SGSN Address, TEID, QoS Negotiated, Negotiated Evolved ARP, serving network identity, CGI/SAI, User CSG Information, RAT type, MS Info Change Reporting support indication, NRSN) message to each GGSN concerned. The SGSN shall send the serving network identity to the GGSN. NRSN indicates SGSN support of the network requested bearer control. The inclusion of the Negotiated Evolved ARP IE indicates that the SGSN supports the Evolved ARP feature. If the new SGSN did not receive a Negotiated Evolved ARP IE in the SGSN Context Response message from the old SGSN then the new SGSN shall derive this value from the Allocation/Retention Priority of the QoS profile negotiated according to Annex E of TS 23.401 [89]. Each GGSN updates its PDP context fields and returns an Update PDP Context Response (TEID, Prohibit Payload Compression, APN Restriction, MS Info Change Reporting Action, CSG Information Reporting Action, BCM, Negotiated Evolved ARP) message. The GGSN sets the Negotiated Evolved ARP based on local policy or PCC. The Allocation/Retention Priority of the QoS Profile Negotiated is derived from the Evolved ARP according to the mapping principles of TS 23.401 [89], Annex E. The Prohibit Payload Compression indicates that the SGSN should negotiate no data compression for this PDP context. The SGSN shall apply the Negotiated Evolved ARP if received from the GGSN.
8）new 3G-SGSN发送update context request（新SGSN地址、TEID、协商的QOS、协商的演进ARP、服务网络ID、CGI/SAI，用户CSG信息，RAT类型，MS信息变化报告支持指示、NRSN）消息给每个关联的GGSN。SGSN应发送服务网络ID给GGSN。NRSN指示SGSN支持网络侧请求的承载控制。协商的演进ARP IE指示SGSN支持演进的ARP特性。如果new SGSN没有在从old SGSN来的SGSN Context Response消息中得到这个IE，那new SGSN应根据TS23.401的附录E的方法通过QOS profile里的分配/保持优先级来获取这个值。每个GGSN更新它的PDP上下文字段并返回一个update PDP context response（TEID，禁止payload压缩、APN限制、MS信息变化报告行动、CSG信息报告行动、BCM、协商的演进ARP)消息。GGSN根据本地策略或PCC设置协商的演进ARP。协商的QOS profile里的ARP是根据TS23.401的附录E的映射原则，从演进的ARP值中得到的。禁止payload压缩指示SGSN应为这个PDP上下文协商无数据压缩。SGSN如果从GGSN收到协商的演进ARP的话，则应应用这个值。
9) The new 3G SGSN informs the HLR of the change of SGSN by sending an Update GPRS Location (SGSN Number, SGSN Address, IMSI, IMEISV, Homogenous Support of IMS Over PS Sessions) message to the HLR. IMEISV is sent if the ADD function is supported. Homogenous Support of IMS Over PS Sessions indicates whether or not "IMS Voice over PS Sessions" is supported homogeneously in all RAs in the serving SGSN.
10) The HLR sends a Cancel Location (IMSI, Cancellation Type) message to the old 2G SGSN. The old 2G SGSN removes the MM and PDP contexts if the timer described in step 3 is not running. If the timer is running, the MM and PDP contexts are removed when the timer expires. The old 2G SGSN acknowledges with a Cancel Location Ack (IMSI) message.
11) The HLR sends an Insert Subscriber Data (IMSI, Subscription Data) message to the new 3G SGSN. The 3G SGSN constructs an MM context for the MS and returns an Insert Subscriber Data Ack (IMSI) message to the HLR. If the S6d interface is used between S4-SGSN and HSS the messages "Insert Subscriber Data" and "Insert Subscriber Data Ack" are not used. Instead the Subscription Data is sent by HSS in the message Update Location Ack (Step 15).
9）new 3G-SGSN通知HLR关于SGSN的变化，通过发送update GPRS location（SGSN number、SGSN地址、IMSI、IMEISV、IMS over PS会话的同质支持）给HLR来通知它。如果支持ADD功能则发送IMEISV。IMS over PS会话的同质支持指示"IMS voice over PS会话”的能力在服务SGSN的所有RA中都能被等价的支持（即采取相同的策略）。
10）HLR发送cancel location（IMSI、取消类型）消息给old 2G-SGSN。Old 2G-SGSN发现，如果在步骤3描述的计时器没有运行的话，那它将移除MM和PDP上下文。如果这个计时器运行了，那MM和PDP上下文将在计时器超时后被移除。Old 2G SGSN发送Cancel Location Ack(IMSI)消息进行确认。
11）HLR发送一个Insert Subscriber Data(IMSI、签约数据）消息给new 3G-SGSN。3G-SGSN为MS构建一个MM和PDP上下文并且返回一个Insert Subscriber Data ACK（IMSI）消息给HLR。如果在S4-SGSN和HSS之间使用的是S6d接口，则消息"Insert Subscriber Data"和"Insert Subscriber Data ACK"将不再使用。作为替代，这个签约数据将在由HSS发过来的"update location ack"消息中携带。（步骤15）
12) The HLR acknowledges the Update GPRS Location by returning an Update GPRS Location Ack (IMSI, GPRS Subscriber Data (only if S6d interface is used)) message to the new 3G SGSN.
13) If the association has to be established, if Update Type indicates combined RA / LA update with IMSI attach requested, or if the LA changed with the routeing area update, the new SGSN sends a Location Update Request (new LAI, IMSI, SGSN Number, Location Update Type) to the VLR. Location Update Type shall indicate IMSI attach if Update Type in step 1 indicated combined RA / LA update with IMSI attach requested. Otherwise, Location Update Type shall indicate normal location update. When the SGSN does not provide functionality for the Intra Domain Connection of RAN Nodes to Multiple CN Nodes, the VLR number is derived from the RAI. When the SGSN provides functionality for Intra Domain Connection of RAN Nodes to Multiple CN Nodes, the SGSN uses the RAI and a hash value from the IMSI to determine the VLR number. The 3G SGSN starts the location update procedure towards the new MSC/VLR upon receipt of the first Insert Subscriber Data message from the HLR in step 12). The VLR creates or updates the association with the 3G SGSN by storing SGSN Number. In networks that support network sharing, the Location Update Request includes the identity of the selected core network operator if the new 3G-SGSN has received this information from the RNS, as described in TS 23.251 [83].
12）HLR确认GPRS的位置更新，并返回一个update GPRS location ACK（IMSI、GPRS签约数据(仅当S6d接口时才使用)）消息给new 3G-SGSN。
13)如果关联需要建立，也就是更新类型指示了带有IMSI附着的联合的RA/LAU请求，或在RAU时发生了LA的变化，那么new 3G SGSN发送Location Update Request(新LAI、IMSI、SGSN编号、Location Update Type)给VLR。Location Update Type应指示为IMSI附着---如果在步骤1的更新类型指示的是带有IMSI附着请求的联合RA/LAU。除此以外，Location Update Type应指示为一个正常的Location Update。当SGSN不为多个CN节点提供到RAN节点的域内连接功能的话，VLR编号将从RAI获取。当SGSN提供这个功能时，SGSN使用RAI以及从IMSI得到的一个哈希函数来决定VLR编号。3G SGSN一旦在步骤12接收到从HLR来的Insert Subscriber Data消息，将开始到new MSC/VLR的位置更新流程。VLR通过存储SGSN编号来创建或更新与3G SGSN的关联。如果网络侧支持网络共享，并且new 3G-SGSN从RNS收到了这个信息的话，Location Update Request将指示选择的核心网络运营商ID，在TS23.251描述。
14) If the subscriber data in the VLR is marked as not confirmed by the HLR, the new VLR informs the HLR. The HLR cancels the old VLR and inserts subscriber data in the new VLR:
a) The new VLR sends an Update Location (new VLR) to the HLR.
b) The HLR cancels the data in the old VLR by sending Cancel Location (IMSI) to the old VLR.
c) The old VLR acknowledges with Cancel Location Ack (IMSI).
d) The HLR sends Insert Subscriber Data (IMSI, subscriber data) to the new VLR.
e) The new VLR acknowledges with Insert Subscriber Data Ack (IMSI).
f) The HLR responds with Update Location Ack (IMSI) to the new VLR.
14)如果VLR上的签约数据标记为未得到HLR的确认，则new VLR要通知HLR。HLR取消在old VLR上的数据并在new VLR插入新的用户签约数据：
a）new VLR发送update location(new VLR)给HLR。
b) HLR发送cancel location(IMSI)消息给old VLR来取消其上的数据。
c）old VLR发送cancel location ack（IMSI)进行确认。
d）HLR发送插入签约用户数据(IMSI,签约数据）给new VLR。
e）new VLR发送insert subscriber data ack(IMSI)进行确认。
f）HLR发送update location ack（IMSI）给new VLR进行响应。
15) The new VLR allocates a new TMSI and responds with Location Update Accept (VLR TMSI) to the 3G SGSN. VLR TMSI is optional if the VLR has not changed.
16) The new 3G SGSN validate the MS's presence in the new RA. If due to roaming restrictions or access restrictions the MS is not allowed to be attached in the RA, or if subscription checking fails, the new 3G SGSN rejects the routeing area update with an appropriate cause. If the network supports the MOCN configuration for network sharing, the SGSN may, if the MS is not a 'Network Sharing Supporting MS', in this case decide to initiate redirection by sending a Reroute Command to the RNS, as described in TS 23.251 [83] instead of rejecting the routeing area update. If all checks are successful, the new 3G SGSN constructs MM and PDP contexts for the MS. The new 3G SGSN responds to the MS with a Routeing Area Update Accept (P TMSI, P TMSI signature, IMS voice over PS Session Supported Indication, Emergency Service Support) message. The IMS voice over PS Session Supported Indication is set as described in clause 5.3.8.
The Emergency Service Support indicator shall be included when going to UTRAN to inform the MS that Emergency PDP contexts are supported, i.e. the MS is allowed to request activation of emergency PDP context when needed.
15）new VLR分配一个新的VLR TMSI并且响应location update accept(VLR TMSI)给3G SGSN。VLR TMSI是可选的，如果VLR没有发生变化的话。
16）3G SGSN验证在新RA中MS的存在性。如果因为漫游限制或接入限制，MS不允许附着到RA，或者如果签约检查失败，则new 3G SGSN拒绝RAU并给出原因值。如果网络侧支持用于网络共享的MOCN配置，SGSN可以，如果MS是一个不支持网络共享的MS，在这里例子里来决定发送一个Reroute Command给RNS来发起一个重定向（在TS23.251描述）来代替拒绝RAU。如果所有检查都成功，new 3G SGSN构建MS的MM和PDP上下文。New 3G SGSN给MS响应一个RAU accept(P-TMSI、P-TMSI签名、IMS voice over PS会话指示指示、紧急业务支持）消息给MS。IMS voice over PS会话指示指示根据5.3.8章节描述设置。紧急业务支持指示是在UTRAN中通知MS支持紧急PDP上下文，也就是MS允许在需要的时候可以请求激活紧急PDP上下文。
17) The MS acknowledges the new P TMSI by returning a Routeing Area Update Complete message to the SGSN.
18) The new 3G SGSN sends TMSI Reallocation Complete message to the new VLR, if the MS confirms the VLR TMSI.
19) If the MS has uplink data or signalling pending it shall send a Service Request (P TMSI, RAI, CKSN, Service Type) message to the SGSN. Service Type specifies the requested service. Service Type shall indicate one of the following: Data or Signalling.
17)MS返回RAU Complete消息给SGSN来确认对新P-TMSI的分配。
18)New 3G SGSN发送TMSI Reallocation Complete消息给new VLR，如果MS确认了VLR TMSI的话。
19)如果MS有pending状态的上行数据或信令，它应发送一个Service Request（P-TMSI、RAI、CKSN、Service Type）消息给SGSN。Service Type指明了请求的服务。Service Type应指示以下二者之一：数据或信令。
20) If the MS has sent the Service Request, the new 3G SGSN requests the SRNS to establish a radio access bearer by sending a RAB Assignment Request (RAB ID(s), QoS Profile(s), GTP SNDs, GTP SNUs, PDCP SNUs, UE-AMBR, MSISDN, APN, Charging characteristics) message to the SRNS. If Direct Tunnel is established the SGSN provides to the RNC the GGSN's Address for User Plane and TEID for uplink data. The PDCP sequence numbers are derived from the N PDU sequence numbers in step 4) and stored in the SGSN PDP contexts. The SRNS sends a Radio Bearer Setup Request (PDCP SNUs) message to the MS. The MS responds with a Radio Bearer Setup Complete (PDCP SNDs) message. The MS deducts PDCP-SND from its Receive N PDU Number by adding eight most significant bits "1". The SRNS responds with a RAB Assignment Response message. The SRNS shall discard all N PDUs tunnelled from the SGSN with N PDU sequence numbers older than the eight least significant bits of the PDCP SNDs received from the MS. Other N PDUs shall be transmitted to the MS. The MS shall discard all N PDUs with SNDCP sequence numbers older than the eight least significant bits of the PDCP SNUs received from the SRNS. Other N PDUs shall be transmitted to the SRNS. The SRNS negotiates with the MS for each radio bearer the use of lossless PDCP or not regardless whether the old 2G-SGSN used acknowledged or unacknowledged SNDCP for the related NSAPI or not. MSISDN, APN and Charging characteristics are optional parameters and only transferred if SGSN supports SIPTO at Iu-ps.
20)如果MS发送了Service Request，new 3G-SGSN发送一个RAB Assignment Request（RAB ID、QOS Profile、GTP SNDs、GTP SNUs、PDCP SNUs、UE-AMBR、MSISDN、APN、计费特征）消息来请求SRNS来建立一个RAB。如果直接隧道建立，SGSN则给RNC提供上行数据的用户平面GGSN地址和TEID。PDCP序列号从N-PDU序列号派生出来并存储在步骤4的PDP上下文中。SRNS发送Radio Bearer Setup Request(PDCP SNUs)消息给MS.MS发送Radio Bearer Setip Complete（PDCP SNDs）消息做为响应。MS从收到的N-PDU Number加上8位最低有效位1来推导出PDCP-SND。SRNS然后响应一个RAB Assignment Response消息给SGSN。SRNS应检查从SGSN隧道发过来的所有N-PDU，如果发现其SNDCP序列号比SNRS收到的8位最低有效位还要老，则应将其丢弃。其他的MS将被传送给MS。MS也要做比较，如果发现收到的N-PDU的SNDCP序列号要比从SRNS收到的PDCP SNUs的8位最低有效位还要老，则应将其丢弃。SRNS和MS为每个无线承载来协商使用或不使用无损PDCP，而不管是否old 2G-SGSN为相关的NSAPI是使用确认模式还是非确认模式SNDCP。MSISDN、APN和计费特征是仅当在Iu-PS，SGSN支持SIPTO的时候的可选参数。
20a) If the SGSN established Direct Tunnel in step 20) it shall send Update PDP Context Request to the GGSN(s) concerned and include the RNC's Address for User Plane, downlink TEID for data and DTI to instruct the GGSN to apply Direct Tunnel specific error handling as described in clause 13.8. The GGSN(s) update the Address for User Plane and TEID for downlink data and return an Update PDP Context Response.
NOTE 1: The NSAPI value is carried in the RAB ID IE.
NOTE 2: The new SGSN may initiate RAB establishment after execution of the security functions (step 5), or wait until completion of the RA update procedure. For the MS, RAB establishment may occur anytime after the RA update request is sent (step 2).
20a)如果SGSN在步骤20建立了直接隧道，它应发送Update PDP Context Request给相关的GGSN并且包含RNC用户平面地址、下行数据的TEID以及DTI来指示GGSN要应用直接隧道，相关的错误处理流程在章节13.8描述。GGSN更新用于下行数据的用户平面地址和TEID并返回Update PDP Context Response。
注释1：NSAPI的值包含在RAB ID这个IE（信息元素）中。
注释2：New SGSN可以在步骤5的安全功能执行之后发起RAB建立，或者等待直到RAU流程的完成。对于MS，RAB的建立可以在步骤2的RAU请求消息发送出去的任何时候发生。
If the new SGSN is unable to update the PDP context in one or more GGSNs, the new SGSN shall deactivate the corresponding PDP contexts as described in clause "SGSN-initiated PDP Context Deactivation Procedure". This shall not cause the SGSN to reject the routeing area update.
The PDP Contexts shall be sent from old to new SGSN in a prioritized order, i.e. the most important PDP Context first in the SGSN Context Response message. (The prioritization method is implementation dependent, but should be based on the current activity).
The new SGSN shall determine the Maximum APN restriction based on the received APN Restriction of each PDP context from the GGSN and then store the new Maximum APN restriction value.
如果new SGSN不能同一个或多个GGSN更新PDP上下文、new SGSN应将相应的PDP上下文去激活。但这不应该导致SGSN拒绝RAU。
PDP上下文应按照一定优先级顺序从old发向new SGSN，也就是最重要的PDP上下文第一个出现在SGSN Context Response消息中。（优先级的方法取决于具体的实现，但应基于当前的一些活跃事件来决定）。
New SGSN应根据从GGSN接收到的每个PDP上下文的APN限制，来决定最大的APN限制，并且存储这个新的最大APN限制的值。
If the new SGSN is unable to support the same number of active PDP contexts as received from old SGSN, the new SGSN should use the prioritisation sent by old SGSN as input when deciding which PDP contexts to maintain active and which ones to delete. In any case, the new SGSN shall first update all contexts in one or more GGSNs and then deactivate the context(s) that it cannot maintain as described in clause "SGSN-initiated PDP Context Deactivation Procedure". This shall not cause the SGSN to reject the routeing area update.
如果new SGSN不能支持从old SGSN接收到的相同数量的active PDP上下文,new SGSN应使用old SGSN发过来的优先级排序做为参考，以此来决定哪些PDP上下文应保持哪些则应删除。在任意场景，new SGSN应首先更新一个或多个GGSN中的所有上下文，并且将不能保持的上下文去激活。但这不应该导致SGSN拒绝RAU。
In this case, clause 6.13.2.2.1 applies except for steps 3, 4, 6, 7, 8 and 20, as well as clause-specific general statements stated below.
在本例中，章节6.13.2.2.1中的流程步骤除了第3、4、6、7、8和20步，都适用于本例。因此不再列出，以下至列出不同部分。
[attach]280[/attach]
Figure 55-2: steps 3, 4, 6, 7 for A/Gb mode to Iu mode Inter-SGSN Change using S4
Steps 3, 4, 6 and 7 are identical to the Gn/Gp case in clause 6.13.2.2.1, except that:
- Message SGSN Context Request is replaced by message Context Request;
- Parameter PDP Contexts is replaced by parameter EPS Bearer Contexts.
- MM Context and EPS Bearer Context when used at the S16 interface are defined by clause 13.2.2. For RAU between two S4-SGSNs, the old SGSN shall include the APN Restriction, CGI/SAI/RAI change support indication and Change Reporting Action in the Context Response message.
步骤3，4，6，7和6.13.2.2.1中的基于Gn/Gp的例子是相同的，区别在于：
-- 消息SGSN Context Request被Context Request消息替代；
-- 参数PDP Context被参数EPS Bearer Context替代。
-- 在使用S16接口时的MM上下文和EPS承载上下文在13.2.2章定义。对于两个S4-SGSN之间的RAU，old SGSN应在Context Response消息中包含APN Restriction,CGI/SAI/RAI变更支持指示和变更报告指示。
8）Box（B）
[attach]281[/attach]
Figure 55-3: step 8 for A/Gb mode to Iu mode Inter-SGSN Change using S4
NOTE: Steps a) and d) are common for architecture variants with GTP-based S5/S8 and PMIP-based S5/S8. For a PMIP-based S5/S8, procedure step (A1) is defined in TS 23.402 [90]. Steps b) and c) in Figure 55-3 concern GTP-based S5/S8.
注释：步骤a和d对于使用GTP或PMIP的S5/S8来说都是公共的。对于基于PMIP的S5/S8，步骤A1在TS23.402定义。图例55-3的步骤b和c和基于GTP的S5/S8接口有关。
a) The new 3G SGSN sends a Modify Bearer Request (new SGSN Address, TEID, serving network identity, CGI/SAI, User CSG Information, RAT type, MS Info Change Reporting support indication) message to the Serving GW. The SGSN shall send the serving network identity to the Serving GW.
b) The Serving GW informs the P GW(s) about the change of Serving GW Address and TEID, as well as about the RAT type that e.g. can be used for charging, by sending the message Modify Bearer Request (Serving GW Address and TEID, RAT type) to the concerned P GW(s). If dynamic PCC is deployed, and RAT type information needs to be conveyed from the P GW to the PCRF, then the P GW shall send RAT type information to the PCRF as defined in TS 23.203 [88].
a)new 2G SGSN发送Modify Bearer Request(new SGSN地址、TEID、服务网络ID、CGI/SAI、用户CSG信息、RAT类型、MS信息变化报告支持指示）消息给SGW。SGSN应发送服务网络ID给SGW。
b）SGW通过发送Modify Bearer Request消息来通知PGW关于SGW地址和TEID的变化，以及RAT类型（例如可用于计费目的）。如果部署了动态PCC，则RAT类型信息将需要由PGW传递给PCRF，然后PGW应将RAT类型信息发送给在规范TS23.203中定义的PCRF。
c) Each P GW updates its context fields and returns a Modify Bearer Response (MSISDN, P GW address and TEID, Prohibit Payload Compression, MS Info Change Reporting Action, CSG Information Reporting Action) message. The Prohibit Payload Compression indicates that the SGSN should negotiate no data compression for this EPS Bearer context. MSISDN is included if available in the stored UE context.
d) The Serving GW updates the Address for User Plane and TEID for downlink data and return a Modify Bearer Response (Serving GW address and TEID, P GW address and TEIDs (for GTP based S5/S8) or GRE keys (for PMIP based S5/S8) at the PDN GW(s) for uplink traffic, CSG Information Reporting Action) message.
c)每个PGW更新它的上下文字段并返回Modify Bearer Response (MSISDN、PGW地址和TEID、禁止payload压缩、MS信息变化报告行动、CSG信息报告行动）消息。禁止payload压缩指示SGSN不应为这个EPS承载上下文来协商数据压缩。MSISDN如果在存储的UE上下文中有的话也应提供。
d) SGW更新下行数据的用户平面地址和TEID并返回一个Modify Bearer Response (SGW地址和TEID、PGW上用于上行流量的PGW地址和TEID（基于GTP的S5/S8）或GRE密钥（基于PMIP的S5/S8)，CSG信息报告行动）消息。
20 Box（C）
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Figure 55-4: step 10 for A/Gb mode to Iu mode Inter-SGSN Change using S4
Step 10 is identical to the Gn/Gp case in clause 6.13.2.2.1, except that:
- Message SGSN Context Request is replaced by message Context Request;
- Parameter PDP Contexts is replaced by parameter EPS Bearer Contexts.
MM Context and EPS Bearer Context when used at the S16 interface are defined by clause 13.2.2.
步骤10和章节6.13.2.2.1描述的基于Gn/Gp的case是相同的，除了以下部分：
-- 消息SGSN Context Request被Context Request消息替代；
-- 参数PDP Context被参数EPS Bearer Context替代。
在S16接口使用的时候，MM上下文和EPS承载上下文在章节13.2.2定义。
yuws 发表于 2012-6-29 10:24
看了 爱卫生发帖的时间，翻译+打字的速度比我单独看还要快。佩服
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