QoS Overview
Page 58 7210 SAS D, E, K OS Quality of Service Guide
Hierarchical Ingress Policing
Note: Hierarchical Ingress Policing supported only on 7210 SAS-D devices.
Hierarchical ingress policing allows the users to specify the amount of traffic admitted into the
system per SAP. It also allows the user to share the available bandwidth per SAP among the
different FCs of the SAP. For example, user can allow the packets classified as Internet data to use
the entire SAP bandwidth when other forwarding classes do not have traffic.
It provides an option to configure SAP aggregate policer per SAP on SAP ingress. The user should
configure the PIR rate of the aggregate policer. The user can optionally configure the burst size of
the aggregate policer.
The aggregate policer monitors the traffic on different FCs and determines if the packet has to be
forwarded to an identified profile or dropped. The final disposition of the packet is based on the
operating rate of the following:
• Per FC policer
• Per SAP aggregate policer
For more information on the final color assigned of the packet, refer to the command description
of "aggregate-meter-rate" command in the 7210 SAS DEK Services Guide.
A new meter mode “trtcm2” (RFC 4115) is introduced for use only on SAP ingress. When the
SAP aggregate policer is configured, the per FC policer can be only configured in “trtcm2” mode.
The existing meter mode “trtcm” is re-named as “trtcm1” (RFC 2698). The meter modes “srtCM”
and “trtcm1” can be used in the absence of aggregate meter.
NOTE: Before use of per SAP aggregate policer/meter, meter resources must be allocated using
the CLI command config> system> resource-profile> ingress-internal-tcam> sap-aggregate-
meter. Change to the amount of resources allocated for SAP aggregate meter requires a reboot of
the node to take effect. For more information, see the 7210 Basic System Guide.
Service Egress QoS Policies on 7210 SAS-K
Service egress queues are implemented at the transition from the service core network to the
service access network. The advantages of per-service queuing before transmission into the access
network are:
• Per-service egress sub-rate capabilities.
• More granular, fairer scheduling per-service into the access network.
• Per-service statistics for forwarded and discarded service packets.
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