When QPPB is enabled on a SAP IP interface the forwarding class of a packet may change from fc1, the original fc determined by the SAP ingress QoS policy to fc2, the new fc determined by QPPB. In the ingress datapath SAP ingress QoS policies are applied in the first P chip and route lookup/QPPB occurs in the second P chip. This has the implications listed below:
Ingress remarking (based on profile state) is always based on the original fc (fc1) and sub-class (if defined).
The profile state of a SAP ingress packet that matches a QPPB route depends on the configuration of fc2 only. If the de-1-out-profile flag is enabled in fc2 and fc2 is not mapped to a priority mode queue then the packet is marked out of profile if its DE bit = 1. If the profile state of fc2 is explicitly configured (in or out) and fc2 is not mapped to a priority mode queue, then the packet is assigned this profile state. In both cases there is no consideration of whether fc1 was mapped to a priority mode queue.
The priority of a SAP ingress packet that matches a QPPB route depends on several factors. If the de-1-out-profile flag is enabled in fc2 and the DE bit is set in the packet then priority is low regardless of the QPPB priority or fc2 mapping to profile mode queue, priority mode queue or policer. If fc2 is associated with a profile mode queue then the packet priority is based on the explicitly configured profile state of fc2 (in profile = high, out profile = low, undefined = high), regardless of the QPPB priority or fc1 configuration. If fc2 is associated with a priority mode queue or policer then the packet priority is based on QPPB (unless DE=1), but if no priority information is associated with the route then the packet priority is based on the configuration of fc1 (if fc1 mapped to a priority mode queue then it is based on DSCP/IP prec/802.1p and if fc1 mapped to a profile mode queue then it is based on the profile state of fc1).
Table: QPPB interactions with SAP ingress QoS summarizes these interactions.
| Original FC object mapping | New FC object mapping | Profile | Priority (drop preference) | DE=1 override | In/out of profile marking |
|---|---|---|---|---|---|
Profile mode queue |
Profile mode queue |
From new base FC unless overridden by DE=1 |
From QPPB, unless packet is marked in or out of profile in which case follows profile. Default is high priority. |
From new base FC |
From original FC and sub-class |
Priority mode queue |
Priority mode queue |
Ignored |
If DE=1 override then low otherwise from QPPB. If no DEI or QPPB overrides then from original dot1p/exp/DSCP mapping or policy default. |
From new base FC |
From original FC and sub-class |
Policer |
Policer |
From new base FC unless overridden by DE=1 |
If DE=1 override then low otherwise from QPPB. If no DEI or QPPB overrides then from original dot1p/exp/DSCP mapping or policy default. |
From new base FC |
From original FC and sub-class |
Priority mode queue |
Policer |
From new base FC unless overridden by DE=1 |
If DE=1 override then low otherwise from QPPB. If no DEI or QPPB overrides then from original dot1p/exp/DSCP mapping or policy default. |
From new base FC |
From original FC and sub-class |
Policer |
Priority mode queue |
Ignored |
If DE=1 override then low otherwise from QPPB. If no DEI or QPPB overrides then from original dot1p/exp/DSCP mapping or policy default. |
From new base FC |
From original FC and sub-class |
Profile mode queue |
Priority mode queue |
Ignored |
If DE=1 override then low otherwise from QPPB. If no DEI or QPPB overrides then follows original FC’s profile mode rules. |
From new base FC |
From original FC and sub-class |
Priority mode queue |
Profile mode queue |
From new base FC unless overridden by DE=1 |
From QPPB, unless packet is marked in or out of profile in which case follows profile. Default is high priority. |
From new base FC |
From original FC and sub-class |
Profile mode queue |
Policer |
From new base FC unless overridden by DE=1 |
If DE=1 override then low otherwise from QPPB. If no DEI or QPPB overrides then follows original FC’s profile mode rules. |
From new base FC |
From original FC and sub-class |
Policer |
Profile mode queue |
From new base FC unless overridden by DE=1 |
From QPPB, unless packet is marked in or out of profile in which case follows profile. Default is high priority. |
From new base FC |
From original FC and sub-class |