个人在学习5G标准3GPP TS 23501-g51过程中，也发现google的机器翻译实在晦涩难懂，所以个人在借助百度翻译（中国人更懂中文）的同时，人工对每句话进行了校对。
4.2.4 Roaming reference architectures
Figure 4.2.4-1 depicts the 5G System roaming architecture with local breakout with service-based interfaces within the Control Plane.
图4.2.4-1描述了5G System架构，该架构具有Control Plane内service-based的接口的本地分支。
Figure 4.2.4-1: Roaming 5G System architecture- local breakout scenario in service-based interface representation
NOTE 1: In the LBO architecture. The PCF in the VPLMN may interact with the AF in order to generate PCC Rules for services delivered via the VPLMN. The PCF in the VPLMN uses locally configured policies according to the roaming agreement with the HPLMN operator as input for PCC Rule generation. The PCF in VPLMN has no access to subscriber policy information from the HPLMN.
注1：在LBO架构中。VPLMN中的PCF可以与AF交互，以便为经由VPLMN交付的服务生成PCC Rules。VPLMN中的PCF根据与HPLMN运营商签订的漫游协议使用本地配置的策略作为PCC Rule生成的输入。VPLMN中的PCF无法从HPLMN访问订户策略信息。
NOTE 2: An SCP can be used for indirect communication between NFs and NF services within theVPLMN, within the HPLMN, or in within both VPLMN and HPLMN. For simplicity, the SCP is not shown in the roaming architecture.
Figure 4.2.4-3 depicts the 5G System roaming architecture in the case of home routed scenario with service-based interfaces within the Control Plane.
图4.2.4-3描述了在Control Plane内具有service-based的接口的归属路由场景下的5G System漫游架构。
Figure 4.2.4-3: Roaming 5G System architecture - home routed scenario in service-based interface representation
NOTE 3: An SCP can be used for indirect communication between NFs and NF services within the VPLMN, within the HPLMN, or in within both VPLMN and HPLMN. For simplicity, the SCP is not shown in the roaming architecture.
NOTE 4: UPFs in the home routed scenario can be used also to support the IPUPS functionality (see clause 126.96.36.199).
Figure 4.2.4-4 depicts 5G System roaming architecture in the case of local break out scenario using the reference point representation.
Figure 4.2.4-4: Roaming 5G System architecture - local breakout scenario in reference point representation
NOTE 5: The NRF is not depicted in reference point architecture figures. Refer to Figure 4.2.4-7 for details on NRF and NF interfaces.
NOTE 6: For the sake of clarity, SEPPs are not depicted in the roaming reference point architecture figures.
The following figure 4.2.4-6 depicts the 5G System roaming architecture in the case of home routed scenario using the reference point representation.
Figure 4.2.4-6: Roaming 5G System architecture - Home routed scenario in reference point representation
For the roaming scenarios described above each PLMN implements proxy functionality to secure interconnection and hide topology on the inter-PLMN interfaces.
Figure 4.2.4-7: NRF Roaming architecture in reference point representation
NOTE 7: For the sake of clarity, SEPPs on both sides of PLMN borders are not depicted in figure 4.2.4-7.
Figure 4.2.4-8: Void
Operators can deploy UPFs supporting the Inter PLMN UP Security (IPUPS) functionality at the border of their network to protect their network from invalid inter PLMN N9 traffic in home routed roaming scenarios. The UPFs supporting the IPUPS functionality in VPLMN and HPLMN are controlled by the V-SMF and the H-SMF of that PDU Session respectively. A UPF supporting the IPUPS functionality terminates GTP-U N9 tunnels. The SMF can activate the IPUPS functionality together with other UP functionality in the same UPF, or insert a separate UPF for the IPUPS functionality in the UP path (which e.g. may be dedicated to be used for IPUPS functionality). Figure 4.2.4-9 depicts the home routed roaming architecture where a UPF is inserted in the UP path for the IPUPS functionality. Figure 4.2.4-3 depicts the home routed roaming architecture where the two UPFs perform the IPUPS functionality and other UP functionality for the PDU Session.
运营商可以在其网络边界部署支持Inter PLMN UP Security（IPUPS）功能的UPF，以保护其网络在归属路由漫游场景中免受无效的跨PLMN N9流量的影响。VPLMN和HPLMN中支持IPUPS功能的UPF分别由该PDU Session的V-SMF和H-SMF控制。支持IPUPS功能的UPF终结GTP-U N9隧道。SMF可在同一UPF中与其他UP功能一起激活IPUPS功能，或在UP路径中为IPUPS功能插入单独的UPF（例如，可专用于IPUPS功能）。图4.2.4-9描述了归属路由漫游体系结构，在UP路径中插入IPUPS功能的UPF。图4.2.4-3描述了归属路由漫游架构，其中两个UPF为PDU Session执行IPUPS功能和其他UP功能。
NOTE 8: Operators are not prohibited from deploying the IPUPS functionality as a separate Network Function from the UPF, acting as a transparent proxy which can transparently read N4 and N9 interfaces. However, such deployment option is not specified and needs to take at least into account very long lasting PDU Sessions with infrequent traffic and Inter-PLMN handover.
注8：不禁止运营商将IPUPS功能部署为独立于UPF的Network Function，作为透明代理，可透明读取N4和N9接口。然而，未指定此类部署选项，并且至少需要考虑具有不频繁流量和PLMN间切换的非常长的PDU Session。
The IPUPS functionality is specified in clause 188.8.131.52 and TS 33.501 .
Figure 4.2.4-9: Roaming 5G System architecture - home routed roaming scenario in service-based interface representation employing UPF dedicated to IPUPS