The 7705 SAR supports two queue modes: priority mode and profile mode. Users can configure the queue mode using the priority-mode or profile-mode keywords when issuing the config>qos>sap-ingress>queue queue-id queue-mode create command. The default is priority-mode.The queue mode defines how an ingress access packet is categorized as in-profile or out-of-profile.
With priority mode, an access packet’s in-profile or out-of-profile state is based on the dynamic rate of the ingress queue prior to being forwarded to the fabric. When the queue rate is lower than or equal to the configured CIR, the packet is considered in-profile. When the queue rate is higher than the CIR, the packet is considered out-of-profile. The profile state is determined when the packet is scheduled out of the queue, not when the packet is buffered into the queue.
With profile mode, the in-profile or out-of-profile state for packets assigned to a particular forwarding class is explicitly configured using the config>qos>sap-ingress>fc>profile command. This configuration places a forwarding class in a color-aware profile mode. Packets assigned to this forwarding class profile are only marked based on this profile marking if the forwarding class is mapped to a queue configured for profile-mode. If the forwarding class is mapped to a queue configured for priority-mode, the forwarding class profile setting is ignored and the packet’s state is defined as in-profile or out-of-profile based on the dynamic rate of the ingress queue.
When the profile in command is executed on a forwarding class that is mapped to a queue operating in profile mode, all packets associated with the class are handled as in-profile. When the profile out command is executed on a forwarding class that is mapped to a queue operating in profile mode, all packets associated with the class are handled as out-of-profile.
When the no profile command is executed on a forwarding class that is mapped to a queue operating in profile mode, the data packets using the forwarding class are marked as in-profile or out-of-profile based on the dynamic rate of the ingress queue relative to its CIR.
Color-aware profiling adds the ability to selectively treat packets received on a SAP as in-profile (green) or out-of-profile (yellow) regardless of the queue forwarding rate. For example, a network operator can color a packet out-of-profile with the intention of preserving in-profile bandwidth for higher-priority packets.
A queue operating in profile mode can support in-profile, out-of-profile, and non-profiled packets simultaneously because multiple forwarding classes with different forwarding class profiles can be assigned to a single queue.
All non-profiled and profiled packets are forwarded through the same ingress access queue to prevent out-of-sequence forwarding. Profiled packets that are in-profile are counted against the total number of packets flowing through the queue that are marked in-profile.This reduces the amount of CIR available to non-profiled packets, causing fewer packets to be marked in-profile. Profiled packets that are out-of-profile are not counted against the total number of packets flowing through the queue that are marked in-profile. This ensures that the number of non-profiled packets marked in-profile is not affected by the profiled out-of-profile packet rate.
A SAP ingress queue operating in profile mode is classified as high-priority or low-priority based on the configuration of the forwarding class profile rather than on the high-priority or low-priority configuration specified for DSCP or dot1p. All non-profile packets flowing through the queue are considered high priority. Profiled in-profile packets are also handled as high priority, while profiled out-of-profile packets are handled as low priority.
For SAP ingress queues in profile mode, statistics are collected for color in (for a forwarding class configured for profile in), color out (for a forwarding class configured for profile out), and uncolor (for a forwarding class configured for no profile).