Shaping

ATM layer egress shaping is supported for CBR, rt-VBR, and nrt-VBR VCs. A CBR VC is shaped to a single leaky bucket with the parameter PIR from the traffic descriptor. An rt-VBR VC or an nrt-VBR VC is shaped to two leaky buckets with parameters PIR and SIR, BT from the traffic descriptor, where BT is the Burst Tolerance and is a function of the MBS parameters configured by the user. The traffic rates and shaping parameter that are configured in the sap-egress QoS policy are not used at ATM SAPs.

In order to enforce the Service Level Agreement, ATM layer ingress policing is supported at ingress, so no shaping is needed. At ingress, after optional policing is applied, packet level queue-based soft-policing is supported per the service ingress QoS policy applied to the ATM SAP.