The service-egress policy defines the Service Level Agreement (SLA) for service packets as they egress on a SAP configured on either an access port or a hybrid port. Service-egress QoS policies allow the definition of queue parameters along with a remark policy.
With the default service egress policy, the system allocates one queue. The eight FCs are mapped to use the same queue. The user has the option to define up to eight queues per policy and define the FC-to-queue mapping. In addition, the policy allows the user to define the queue parameters. The hardware does not support a linear range of values for the rate parameters (CIR and PIR). The user can specify the computation method of rates to match the rates supported by the hardware, through the configuration of adaptation rules.
The SAP egress policy for access SAPs supports the following:
per-SAP egress queuing and shaping, hierarchical shaping on SAP egress (with three levels of shaping) with a per-FC/queue shaper, per-SAP aggregate shaper and per-port egress rate shaper
SAP egress queues, shaping, and scheduling
On the 7210 SAS-K 2F1C2T and 7210 SAS-K 2F6C4T, hardware queues are allocated in groups of two, and on the 7210 SAS-K 3SFP+ 8C, hardware queues are allocated in groups of four; these grouped queues are reserved for use by the SAP even if the user specifies an odd value. The 7210 SAS-K 2F1C2T and 7210 SAS-K 2F6C4T support two, four, six, or eight queues per SAP. The 7210 SAS-K 3SFP+ 8C supports four or eight queues per SAP.
Provides an option to configure the FC-to-queue map, allowing the user to assign the packets classified into a particular FC to any of the queues configured for the SAP.
On SAP egress, only a single queue can be configured per FC and all traffic (unicast and BUM) share the single queue.
Allows configuration of queue shaper rate (CIR/PIR), CBS and MBS, queue priority and weight. The assigned priority and weight is used to determine the priority and weight of the queue in both the CIR and PIR scheduling loop.
Allows configuration of WRED slopes (per queue) – high-slope and low-slope. One of the configured WRED slopes is used to allocate buffer to the packet. In-profile packets use the high-slope and out-of-profile packets use the low-slope. The profile of the packet is determined at the ingress (access uplink port ingress or Access SAP ingress) and carried through to be used at SAP egress to determine the WRED slope to apply and also to determine the egress marking value to use (if remarking/marking is enabled).
Supports Strict Priority (SP) scheduling and Weighted-Fair Queuing (WFQ) scheduling for SAP egress queues.
SAP egress remarking/marking
Dot1p and/or IP DSCP marking must be supported on access SAP egress. Configuration of per FC dot1p and/or IP DSCP marking is supported, with the capability to assign different dot1p and/or IP DSCP values for in-profile and out-of-profile packets. In addition, support for marking DEI value is available.
The following is a sample configuration output showing the default access SAP egress QoS.
*A:SAH01-071>config>qos>sap-egress# info detail
----------------------------------------------
description "Default SAP egress QoS policy."
scope template
no remarking
remark 1
queue 1 create
adaptation-rule cir closest pir closest
rate cir 0 pir max
mbs 60
cbs 10
slope-policy "default"
priority 1
weight 1
exit
fc af create
queue 1
exit
fc be create
queue 1
exit
fc ef create
queue 1
exit
fc h1 create
queue 1
exit
fc h2 create
queue 1
exit
fc l1 create
queue 1
exit
fc l2 create
queue 1
exit
fc nc create
queue 1
exit