学习5G知识，势必要去阅读相关的技术标准，而纯英文的标准协议对于初学者来说是个门槛。

个人在学习5G标准3GPP TS 29244-g30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。

在自己学习的同时，也将翻译内容分享给给广大网友。由于个人能力有限，翻译不到位的地方还请各位网友们指正。

5.4.8 Traffic Steering 流量导向

Traffic Steering refers to the process of applying a specific (S)Gi-LAN traffic steering policy in the PCEF or TDF (or TSSF), or a specific N6-LAN traffic steering policy in the UPF (PDU Session Anchor), for the purpose of steering the subscriber's traffic to appropriate operator or 3rd party service functions (e.g. NAT, antimalware, parental control, DDoS protection) in the (S)Gi-LAN or N6-LAN, per service data flows level or applications level.

Traffic Steering是指在PCEF或TDF中应用特定的Gi LAN流量导向策略，或在UPF中应用特定的N6-LAN流量导向策略，以便将用户的流量导向到Gi LAN或N6-LAN中适当的运营商或第三方服务功能的过程，每个服务数据流级别或应用程序级别。

Application Function influencing traffic routing (see clause 5.6.7 of 3GPP TS 23.501 [28]) also uses traffic steering for the purpose of steering the subscriber's traffic over N6, e.g. to a local access to a Data Network.

影响流量路由的Application Function还使用流量导向来控制用户在N6上的流量，例如到Data Network的本地访问。

The UP function shall set the TRST feature flag in the UP Function Features IE if it supports Traffic Steering (see clause 8.2.25).

如果UP功能支持Traffic Steering，UP功能应在UP功能特性中设置TRST特性标志。

Traffic Steering is supported over the Sxb, Sxc and N4 reference points by instructing the UP function to apply a specific Forwarding Policy, that is locally configured in the UP function and that can be used for the uplink, the downlink or for both directions. A Forwarding Policy is identified by a Forwarding Policy Identifier. Traffic steering is alternatively supported over the N4 reference point by instructing the UP function to route packets according to N6 routing information in the FAR (e.g. providing an IP address in the Outer Header Creation).

通过指示UP功能应用特定的Forwarding Policy，在Sxb、Sxc和N4参考点上支持Traffic Steering，该策略在UP功能中本地配置，并且可用于上行链路、下行链路或两个方向。Forwarding Policy由Forwarding Policy Identifier标识。或者，通过指示UP功能根据FAR中的N6路由信息路由分组，在N4参考点上支持流量导向。

When so instructed, the UP function shall perform the necessary actions to enforce the forwarding policy referenced by the CP function, e.g. performing packet marking and routing the traffic towards the service functions within the (S)Gi-LAN or N6-LAN.

当收到指示时，UP功能应执行必要的操作，以执行CP功能引用的转发策略，例如，执行数据包标记并将流量路由到Gi LAN或N6-LAN内的业务功能。

See 3GPP TS 23.203 [7], 3GPP TS 29.212 [8] and 3GPP TS 23.501 [28].

参见3GPP TS 23.203 [7]，3GPP TS 29.212 [8]和3GPP TS 23.501 [28]。

The CP function shall control Traffic Steering towards SGi-LAN, N6-LAN or N6 in the UP function by:

CP功能应通过以下方式控制向UP功能中的SGi LAN、N6-LAN或N6的Traffic Steering：

- creating the necessary PDRs to represent the service data flows or applications to be steered;

-创建必要的PDR来表示要控制的业务数据流或应用程序；

- creating a FAR with the Forwarding Policy IE including the Forwarding Policy Identifier set to the Traffic Steering Policy Identifier, or creating a FAR with a Outer Header Creation with the destination IP address; and

-使用Forwarding Policy ID创建FAR，包括设置为Traffic Steering Policy Identifier的Forwarding Policy Identifier，或者使用目的地IP地址创建Outer Header Create FAR；以及

- associating the FAR to the above PDRs of the PFCP session.

-将FAR与PFCP会话的上述PDR相关联。

The CP function shall control the processing of the traffic received from the (S)Gi-LAN or N6-LAN in the UP function as specified in the rest of this specification for traffic received from any other interface, but with PDR(s) including a PDI with the Source Interface indicating "SGi-LAN/N6-LAN". The UP function shall distinguish packets coming from (S)Gi-LAN/N6-LAN based on local configuration.

CP功能应按照本规范其余部分的规定，控制UP功能中从Gi LAN或N6-LAN接收的流量的处理，以处理从任何其他接口接收的流量的规定，但PDR包括PDI，Source Interface指示“SGi LAN/N6-LAN”。UP功能应根据本地配置区分来自Gi LAN/N6-LAN的数据包。