QoS Policies
7210 SAS D, E, K OS Quality of Service Guide Page 39
In srtcm mode, the meter’s the CBS and MBS token buckets are replenished at single rate, that is,
CIR . In trtcm1 mode, the meter implements the policing algorithm defined in RFC2698 and
trtcm2 implements the policing algorithm defined in RFC4115.
The meter mode supported for different QoS policies are different. In other words, not all the
meter modes are supported for all the QoS policies (For example, trtcm2 mode is supported only
for service ingress policies).
Color-Aware and Color-blind Policing/Metering
In color-aware policing user can define the color of the packet using the ingress classification
rules. The color (also called the profile) assigned to the packet at ingress is used by the meter.
Color/Profile can be assigned on ingress either by enabling DEI classification as done on access
ports or by assigning profile based on either Dot1p or DEI as done on network ports and access-
uplink ports.
A color-aware meter would treat those packets with respect to the color/profile assigned to the
packet as follows:
• If the packet is pre-colored as in-profile (or also called as Green colored packets) then
depending on the burst size of the packet, the meter can either mark it in-profile or out-
profile. If the packet is within the CBS limit, it is assigned a profile value of ‘in-profile’
(or color value of green). If the packet exceeds the CBS limit, then it is reassigned a
profile value of ‘out-profile’ (or color value of yellow).
• If the packet is pre-colored as out-profile (also called as Yellow colored packets) then even
if the packet burst is lesser than the current available CBS, it would not be marked as in-
profile. Instead it is checked against the MBS limit directly and is assigned a profile value
of out-profile (or color value of yellow) if it is within the MBS limit.
• If the packet burst is higher than the MBS then it would be marked as Red and would be
dropped by meter at ingress.
In color-blind policing, the profile/color assigned to the packet on ingress is ignored. The CIR and
PIR rate configured for the meter is used to determine the final color/profile for the packet. If the
packet is within the CIR, then the final profile/color assigned to the packet is in-profile/green and
if the packets exceeds the CIR and is within the PIR, then the final profile/color assigned to the
packet is out-of-profile/yellow. Packets that exceed the PIR rate are dropped.
The profile marked by the meter on ingress is used to determine the packets eligibility to be
enqueued into a buffer at the egress (when a slope policy is configured at the egress).
The 7210 SAS device supports color-aware policing at the network ingress by default. At service
ingress, user is provided an option to use either color-aware policing or color-blind policing.
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