Configures an enforcer for classified traffic based on a two rate three color
meter (trTCM) mode. The trTCM as defined in RFC 2698 meters a traffic stream and
processes its packets based on two rates – CIR and Peak Information Rate
(PIR), and their associated burst sizes - BC and BP (Peak Burst Size).
- trtcm-color-blind - Two rate
three color meter in color-blind mode
- trtcm-color-aware - Two rate
three color meter in color-aware mode
- <0-1000000> –
Configures the CIR from 0 - 1000000 kilobits per second
- <0-16000000> –
Configures the BC from 0 - 1600000 bytes.
- <0-1000000> –
Configures the PIR from 0 - 1000000 kilobits per second
- <0-16000000>
– Configures the BP from 0 - 1600000 bytes
The meter operates in one of two modes. In the color-blind mode, the meter
assumes that the packet stream is uncolored. In color-aware mode the meter assumes
that some preceding entity has pre-colored the incoming packet stream so that each
packet is either green, yellow, or red. The marker (re)colors an IP packet
according to the results of the meter. The color is coded in the DS field [RFC
2474] of the packet.
The behavior of the meter is specified in terms of its
mode and two token buckets, P and C, which are based on the rates PIR and CIR,
respectively. The maximum size of the token bucket P is BP and the maximum size of
the token bucket C is BC.
The token buckets P and C are initially (at time
0) full, that is, the token count Tp(0) = BP and the token count Tc(0) = BC.
Thereafter, the token count Tp is incremented by one PIR times per second up to BP
and the token count Tc is incremented by one CIR times per second up to
BC.
When a packet of size B bytes arrives at time t, the following happens
if trTCM is configured to operate in color-blind mode:
- If Tp(t)-B < 0, the packet
is red, else
- if Tc(t)-B < 0, the packet
is yellow and Tp is decremented by B, else
- The packet is green and both
Tp and Tc are decremented by B.
When a packet of size B bytes arrives at time t, the following happens
if trTCM is configured to operate in color-aware mode:
- If the packet has been
pre-colored as red or if Tp(t)-B < 0, the packet is red, else
- if the packet has been
pre-colored as yellow or if Tc(t)-B < 0, the packet is yellow and Tp is
decremented by B, else
- the packet is green and both
Tp and Tc are decremented by B.
The trTCM can be used to mark a IP packet stream in a service, where
different, decreasing levels of assurances (either absolute or relative) are given
to packets which are green, yellow, or red. Refer to RFC 2698 for more information
on other aspects of trTCM.
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