3Com 3032 Configuration Manual page 681

Physical Interface Line
Rate
LR Configuration
Shape all the flows on Ethernet interface 1.
[Router] interface ethernet1
[Router-Ethernet1] qos gts any cir 45000000 cbs 5800000 ebs 5800000
By using the physical interface line rate (LR), the total rate for sending packets
(including the emergency packet) on a physical interface can be limited.
LR also uses the token bucket to perform the traffic control. If LR is configured in
an interface of the router, the LR token bucket first processes all the packets sent
by this interface. If the token bucket has sufficient tokens, the packet can be sent;
otherwise, the packet enters the QoS queue for congestion management. Thus,
the packet traffic through this physical interface can be controlled.
Figure 216 Schematic diagram of LR processing
incoming packets
classify
As the token bucket is used to control the traffic, when there is any token in the
token bucket, the burst transmission of the packet is allowed. When there is no
token in the token bucket, the packet cannot be sent until a new token is
generated in the token bucket. Thus, there is a limitation that packet traffic cannot
be larger than the generating speed of the token, therefore, it realizes that the
traffic is limited and burst traffic is allowed to pass through at the same time.
Compared with CAR, LR can limit all the packets passing through the physical
interface. CAR is implemented in the IP layer and is ineffective on the packets that
are not processed by the IP layer. It is simple to use LR when the user only requires
the limitation of all packets.
To configure the physical interface line rate, perform the following configurations
in the interface view.
Table 717 Configure the Physical Interface LIne Rate
Operation
Configure the physical interface
bandwidth
Delete the configured physical interface
bandwidth
By default, the line rate is not performed on the physical interface.
Tokens enter bucket
at the given speed
queue
Token Bucket
buffer
Command
qos lr cir committed-rate [ cbs
burst-size [ ebs excess-burst-size ]
]
undo qos lr
Physical Interface Line Rate
outgoing packets
677