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 data path, SAP ingress QoS policies are applied in the first P chip and route lookup/QPPB occurs in the second P chip. This has the following implications:
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, 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, 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, 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, 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, the packet priority is based on QPPB (unless DE=1). If no priority information is associated with the route, the packet priority is based on the configuration of fc1. If fc1 mapped to a priority mode queue, the priority is based on DSCP/IP prec/802.1p. If fc1 mapped to a profile mode queue, the priority 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: 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: 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: high priority |
From new base FC |
From original FC and sub-class |