3Com MSR 50 Series Configuration Manual page 1631

Traffic Evaluation and Token Bucket 1631
Figure 460 TS diagram
For example, in the implementation shown in Figure 461, Router A sends packets
to Router B. And Router B implements TP on those packets, and directly drops
exceeding traffic.
Figure 461 TS implementation
To reduce packets dropping, GTS can be used for the packets on the egress
interface of Router A. The packets beyond the traffic features of GTS will be stored
in Router A. While sending the next set of packets, GTS will take out those packets
from buffer or queues and send them. Thus, all the packets sent to Router B
accord with the traffic regulation of Router B.
Line Rate on Physical Port
On a physical interface, you can enforce line rates below the physical line rate to
limit the overall transmitting rate (including the rate sending critical packets).
LR also uses Token Bucket for traffic control. If LR is configured on an interface of a
router, all packets to be sent via the interface will be first handled by Token Bucket
of LR. If there are enough tokens in Token Bucket, then those packets can be
forwarded; otherwise, those packets will be put into QoS queues for congestion
management, so that the packet traffics through the physical port can be
managed.