Samsung Ubigate iBG3026 Configuration Manual page 220

CHAPTER 19. QoS
Green action
Permit/mark-dscp/
drop
Token Bucket(T
Size = CBS
Packet arrival
Packet
classification
The CIR will be specified in Kbps. CBS and EBS will be specified in Kbits.
CBT is defined by the relationship(CIR = CBS/CBT). The token filling
process has to run at least every CBT milliseconds, without which CIR cannot
be sustained. It is recommended that CBS be large enough for CBT to be at
least 1 second. Therefore it is sufficient for the token filler to execute every 1
second and fill CBS number of tokens into the Tc and Te buckets.
In our implementation, we will execute the token filler every 100 ms.
This process will replenish tokens in all buckets configured on all interfaces in
the system. Running the token filler more frequently results in more frequent
and incremental updates to the token bucket, which can result in a smoother
traffic pattern. This process will execute within the context of the forwarding
task(tRxPoll) so that no context switches are involved, leading to better
performance.
182
Yes
Is Tc full?
No
Tc
)
e
tokens
Insufficient
Get
tokens
'pkt size' number
of tokens
Green packet
Green action
Permit/mark-dscp/
drop
Packets sent for further processing
Figure 19.5 Single Rate Three Color Marking
Is Tc full?
No
Te
tokens
Get
'pkt size' number
of tokens
Yellow packet
Yellow action
Permit/mark-dscp/
drop
© SAMSUNG Electronics Co., Ltd.
Yes
Drop
Token Bucket(T )
e
Size = EBS
Out-of profile
packet
Red packet
Red action
Permit/mark-dscp/
drop