Samsung Ubigate iBG2016, Configuration Manual

Page: 228 / 744

CHAPTER 10. QoS
192
© SAMSUNG Electronics Co., Ltd.
Figure 10.6 Two Rate Three Color Marking
The CIR and PIR will be specified in Kbps. CBS and PBS will be specified in
Kbits. CBT and PBT are defined by the relationships(CIR = CBS/CBT) and
(PIR = PBS/PBT). The period of the token filling process should at least be
equal to the lesser of CBT and PBT milliseconds. Without which CIR and PIR
cannot be sustained. It is recommended that CBS and PBS be large enough so
that CBT and PBT are 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 bucket and PBS number of tokens into the
Tp bucket. However, in our implementation the token filler will run every 100
ms. Note that the same token-filling process will replenish tokens in all
srTCM and trTCM token buckets.
Is Tc full?
Get
‘pkt size’ number
of tokens
Tc
No
tokens
Green packet
Green action
Permit/mark-dscp/
drop
Packets sent for further processing
Yes
Insufficient
tokens
Is Tc full?
Get
‘pkt size’ number
of tokens
Tp
No
tokens
Yes
Drop
Token Bucket(Tp)
Size = PBS
(PBS >= CBS)
Token Replenish
Process Fill tokens
at rate = CIR
Executes every 100ms
Token Bucket(Tc)
Size = CBS
Packet
classification
Packet arrival
Out-of profile
packet
Red packet
Red action
Permit/mark-dscp/
drop
Yellow packet
Yellow action
Permit/mark-dscp/
drop
Yes
Token Replenish
Process Fill tokens
at rate = PIR
Executes every 100ms
(PIR >= CIR)