The following article explains how CoS works on an MX Series Aggregation Device in Junos Fusion Provider Edge and why the client could receive half of the Bandwidth if target-mode is not in use.

Junos implements Shaping-rate on an interface manner. An AE interface can operate in two modes: Scale and Replication modes.

Junos Fusion treats the cascade ports connecting the aggregation device to the satellite device as aggregated Ethernet ports with aggregation done automatically without configuration. By default the Junos Fusion implementation of hierarchical CoS applies the scheduler parameters across all cascade ports in scale mode. Because scale mode divides the configured shaper equally across the cascade ports, traffic drops can start before a customer reaches its committed rate for a particular flow. Starting with Junos OS Release 18.1R1, you can set all cascade ports on an aggregation device to be in replicate mode, thereby copying scheduler parameters to each level of the aggregated interface member links, and automatically target all of an extended port’s traffic to a specific cascade port.

Junos implements Shaping-rate on an interface manner. An AE interface can operate in two modes: Scale and Replication modes.
The scale mode is also referred to as an equal division mode, so shaping-rate on AE interface will be divided equally to member links. If an AE interface has shaping-rate of 8m, then each member interface will have 4m shaping.
The replication mode means each member link has the same shaping-rate as AE interface. If an AE interface has shaping-rate of 8m, then each member interface will have 8m shaping-rate.

To do this, simply enable target-mode for the satellite device at the [edit chassis satellite-management fpc fpc-number] hierarchy level. For example: