本帖最后由 爱卫生 于 2012-5-19 23:34 编辑
Modification procedures modify parameters that were negotiated during an activation procedure for one or several PDP contexts. An MS, a GGSN, an SGSN, or an RNC can request a modification procedure. The Modification procedures may possibly be triggered by the HLR as explained in subclause "Insert Subscriber Data Procedure" or by an RNC in a RAB Release or an RNC-initiated RAB Modification procedure. An MS and SGSN can also decide about modification procedures after an RNC-initiated Iu release. 修改流程可以用于对一个或多个通过激活的PDP上下文中,通过激活流程所协商出的参数进行修改。修改流程也可以通过HLR来触发(插入用户签约数据流程章节)或由RAB释放流程或RNC发起的RAB修改流程中的RNC网元来触发。MS和SGSN可以决定在RNC发起的Iu释放流程后怎样去执行修改流程。 The following parameters can be modified: - QoS Negotiated; - Radio Priority; - Packet Flow Id; - PDP Address (in case of the GGSN-initiated modification procedure); - TFT (in case of MS- or GGSN-initiated modification procedure); - BCM (in case of GGSN-initiated modification procedure); and - Usage of Direct Tunnel. 以下参数可以修改: - 协商的Qos; - 无线优先级 - PFI - PDP地址 - TFT - BCM - 是否使用直接隧道 The SGSN can request the modification of parameters by sending a Modify PDP Context Request message to the MS. A GGSN can request the modification of parameters by sending an Update PDP Context Request message to the SGSN. An MS can request the modification of parameters by sending a Modify PDP Context Request message to the SGSN. An RNC can request an Iu release by sending an Iu Release Request message to the SGSN. After Iu release the MS and SGSN shall modify the PDP contexts according to the rules defined in clause "RNC-Initiated PDP Context Modification Procedure". An RNC can request the release of a radio access bearer. After RAB release the MS and the SGSN shall locally modify the corresponding PDP context according to rules defined in the clause "RAB Release-Initiated Local PDP Context Modification Procedure". SGSN通过发送Modify PDP Context Request消息给MS来发起对PDP上下文参数的修改。GGSN则是通过发送Update PDP Context Request消息给SGSN来对参数进行修改。MS可以发送Modify PDP Context Request消息给SGSN来对参数进行修改。RNC可以发送Iu Release Request消息给SGSN来请求释放Iu资源。Iu释放之后,MS和SGSN可以根据章节"RNC发起的PDP上下文修改流程"中的说明来请求更新PDP上下文参数。RNC可以请求释放掉一个RAB,在RAB释放后,MS和SGSN应本地修改相应的PDP上下文参数,这个规则在章节“RAB release-Initiated Local PDP Context Modication Procedure"中说明。 A trace may be activated while a PDP context is active. To enable trace activation in a GGSN, the SGSN shall send an Update PDP Context Request message to the GGSN. If PDP context modification is performed only to activate a trace, the SGSN shall not send a Modify PDP Context Request message to the MS. The GGSN shall send an Update PDP Context Request modification to the SGSN when modifying the APN restriction. If the PDP context modification is performed only to change the value of the APN restriction, the SGSN shall not send a Modify PDP Context Request message to the MS. If the GGSN has stored information that the current SGSN supports the reporting of CGI/SAI/RAI changes, to enable or disable CGI/SAI/RAI change reporting for an already active PDP context, the GGSN shall send an Update PDP Context Request message to the SGSN. The SGSN shall behave according to clause 15.1.1a. An RNC may request the modification of some negotiated RAB related QoS parameters by sending a RAB Modify Request. 当PDP上下文是active时可以对其进行追踪。为了激活GGSN侧的追踪,SGSN应发送update pdp context request消息给GGSN。如果PDP上下文修改只是为了来激活这个追踪,则SGSN不应给MS发送modify pdp context request消息。 GGSN在需要修改APN限制时,应发送update pdp context request修改给SGSN,如果这个PDP上下文修改只是为了改变APN限制的值,则SGSN不应给MS发送modify pdp context request消息。 如果GGSN保存了当前SGSN支持报告CGI/SAI/RAI等位置变化相关的信息,如果要enable或disable针对一个已经激活的PDP上下文的CGI/SAI/RAI的变化报告,则GGSN应发送update pdp context request消息给SGSN。SGSN应按照章节15.1.1.a的说明来处理。 9.2.3.1 SGSN-Initiated PDP Context Modification Procedure The SGSN-Initiated PDP Context Modification procedure is illustrated in Figures 70a and 70b. SGSN发起的PDP上下文修改流程在图例70a和70b中描述:
Figure 70a: SGSN-Initiated PDP Context Modification Procedure, A/Gb mode
Figure 70b: SGSN-Initiated PDP Context Modification Procedure, Iu mode 1) The SGSN may send an Update PDP Context Request (TEID, NSAPI, QoS Negotiated, Trace Reference, Trace Type, Trigger Id, OMC Identity, serving network identity, CGI/SAI/RAI change support indication, DTI) message to the GGSN. If Direct Tunnel is established the SGSN provides to the GGSN the RNC's Address for User Plane and TEID for downlink data and shall include the DTI to instruct the GGSN to apply Direct Tunnel specific error handling as described in clause 13.8. The QoS Negotiated may be equal to, an upgrade or a downgrade compared to the current QoS of the PDP context. The SGSN shall send the serving network identity to the GGSN. If QoS Negotiated received from the SGSN is incompatible with the PDP context being modified, the GGSN rejects the Update PDP Context Request. The GGSN operator configures the compatible QoS profiles. The SGSN shall include Trace Reference, Trace Type, Trigger Id, and OMC Identity in the message if GGSN trace is activated while the PDP context is active. The SGSN shall copy Trace Reference, Trace Type, and OMC Identity from the trace information received from the HLR or OMC. 1)SGSN可以发送Update PDP Context Request (TEID, NSAPI, QoS Negotiated, Trace Reference, Trace Type, Trigger Id, OMC Identity, serving network identity, CGI/SAI/RAI change support indication, DTI) 给GGSN。如果直接隧道建立了,则SGSN应给GGSN提供RNC侧的用户面地址和TEID,以用于下行方向用户数据的传递,并且应包含一个DTI指示位来指示GGSN应用直接隧道(特定的错误处理说明在13.8章节中提到)。协商的Qos可以是针对PDP上下文当前Qos所做的升级或者降级。SGSN应发送服务网络ID给GGSN。如果从SGSN收到的协商Qos值和要修改的PDP上下文不符,则GGSN将拒绝这个update pdp context request消息。GGSN运营商可以配置兼容的Qps profile。如果GGSN的trace激活了,则SGSN应在消息中包含Trace Reference, Trace Type, Trigger Id, and OMC Identity。SGSN应从HLR或OMC收到的trace信息中拷贝Trace Reference, Trace Type, Trigger Id, and OMC Identity值。 2) The GGSN may restrict QoS Negotiated given its capabilities and the current load or increase the QoS Negotiated based on any external input (e.g. policy control). The GGSN stores QoS Negotiated and returns an Update PDP Context Response (TEID, QoS Negotiated, Prohibit Payload Compression, APN Restriction, Cause, CGI/SAI/RAI change report required) message. The Prohibit Payload Compression indicates that the SGSN should negotiate no data compression for this PDP context. The SGSN shall re-verify and may restrict the QoS Negotiated received from the GGSN against the subscribed QoS profile and additionally restrict the QoS negotiated based on its capabilities and current load. The SGSN shall use this updated QoS Negotiated for the subsequent steps. 3) In A/Gb mode, BSS packet flow context procedures may be executed. These procedures are defined in clause "BSS Context". 4) In Iu mode, radio access bearer modification may be performed by the RAB Assignment procedure. 2)GGSN可以根据自己的支持能力和当前的负荷来限制协商的Qos或者根据一些外部的输入(例如PCRF)来提升协商的Qos。GGSN存储这个协商的Qos并返回Update PDP Context Response (TEID, QoS Negotiated, Prohibit Payload Compression, APN Restriction, Cause, CGI/SAI/RAI change report required)消息。Prohibit Payload Compression指示SGSN应该对这个PDP上下文不要做数据压缩。SGSN应重新验证用户的Qos,通过从GGSN收到的协商Qos值、用户签约的Qos profile以及自身当前的支持能力和负荷情况来决定最终的Qos。SGSN将使用这个最终协商好的Qos用于后续的步骤。 3)在A/Gb模式,BSS PFC流程可以执行。可以参考章节“BSS Context“。 4)在Iu模式,RAB更新可以通过RAB Assignment流程来执行。 5) In case the QoS profile, used as input to step 4 for Iu mode and step 3 for A/Gb mode, have been downgraded during those steps, the SGSN may inform the GGSN about the downgraded QoS profile by sending an Update PDP Context Request to the affected GGSN. The GGSN shall not attempt to renegotiate the QoS profile. The No QoS negotiation indication is set in Update PDP Context Request to indicate to the GGSN that the SGSN does not upgrade the previously negotiated QoS profile and that the GGSN shall accept the provided QoS profile without negotiation. The GGSN confirms the new QoS profile by sending an Update PDP Context Response to the SGSN. If the SGSN established Direct Tunnel in step 4 it shall send Update PDP Context Request and include the RNC's Address for User Plane, TEID for downlink data, No QoS negotiation indication and the DTI. DTI is used to instruct the GGSN to apply Direct Tunnel specific error handling as described in clause 13.8. 6) The SGSN selects Radio Priority and Packet Flow Id based on QoS Negotiated, and may send a Modify PDP Context Request (TI, QoS Negotiated, Radio Priority, Packet Flow Id) message to the MS. If the MS indicated in the MS Network Capability it does not support BSS packet flow procedures, then the SGSN shall not include the Packet Flow Id. In A/Gb mode, the QoS Negotiated shall take into account the Aggregate BSS QoS Profile, if any, returned from the BSS. 5)一旦在步骤4(用于Iu模式)和步骤3(用于A/Gb模式)的Qos profile被降级了,SGSN应通知GGSN这个降级的Qos profile,通过发送update pdp context request给受到影响的GGSN进行通知。GGSN不应尝试重新去协商Qos profile。"无Qos协商"指示应在update pdp context request消息中进行设置,GGSN收到后将接受SGSN新提供的Qos profile而不会重新进行协商。GGSN发送update pdp context response给SGSN进行确认。如果SGSN在步骤4中决定建立直接隧道,SGSN将在update pdp context request消息并且包含RNC侧的用户面地址和TEID,以用于下行方向用户数据的传递,还将包含"无Qos协商指示"以及DTI。 6)SGSN根据协商的Qos来选择无线优先级和PFI,并且发送Modify PDP Context Request (TI, QoS Negotiated, Radio Priority, Packet Flow Id) 消息给MS。如果MS在之前通过MS Network Capability告知网络侧自己不支持BSS Packet flow流程,那SGSN则不应包含PFI。在A/Gb模式,协商的Qos要被考虑进聚合的BSS Qos profile(如果有的话,从BSS返回)。 7) The MS should accept the PDP context modification requested by the network if it is capable of supporting the modified QoS Negotiated. For a successful modification the MS acknowledges by returning a Modify PDP Context Accept message. If the MS is incapable of accepting the new QoS Negotiated, the MS should initiate application level signalling to lower the QoS requirements for the concerned application(s). If this is not possible then the MS shall instead de-activate the PDP context with the PDP Context Deactivation Initiated by the MS procedure. NOTE: In order to facilitate operator control of the QoS an MS should accept a new QoS being assigned by the network even if the QoS is different from the one that the MS uses by default for a particular service type. One reason why the MS may not accept the modified QoS is if it has insufficient internal resources available to support the new QoS. If an APN Restriction is received from the GGSN for this PDP Context, then the SGSN shall store this value for the PDP Context, replacing any previously stored value for this PDP context. The SGSN shall determine a (new) value for the Maximum APN Restriction using any stored APN Restriction and the received APN Restriction. 7)如果MS能够支持修改后协商的Qos,则MS应接受网络侧下发的PDP context修改请求。做为一个成功的修改流程,MS需要返回Modify PDP Context Accept消息进行确认。如果MS不能够接受新的协商的Qos,MS应发起应用层级别的信令(例如HTTP、RTSP等)来请求针对特定的应用来降低对Qos的需求。如果无法从应用层来完成Qos的需求变更,MS可以发起一个PDP上下文去激活流程将PDP上下文去激活。 注释:为了加强运营商对Qos的控制,MS应接受这个新的Qos即使这个Qos与MS上针对特定业务类别所需求的缺省Qos不同。有一个原因,关于为什么不可以接受修改的Qos,可能是因为MS没有足够的内部资源来支持这个新的Qos。 如果从GGSN收到了关于这个PDP上下文的APN限制,那么SGSN应为这个PDP上下文保存这个APN限制值,并且替换掉之前存储的关于这个PDP上下文的老值(old APN限制值)。SGSN应根据存储的APN限制和接收到的APN限制来决定一个新的最大APN限制值。 |