In the BNG application, host queues of all subscribers destined for the same downstream BSAN, for example, all SAPs on the egress port matching the same S-VLAN tag value, are parented to the same Vport which matches the destination ID of the BSAN.
The BNG determines the parent Vport of a subscriber host queue, which has the port-parent option enabled, by matching the destination string associated with the subscriber with the string defined under a Vport on the port associated with the subscriber.
The user configures the dest string match under the egress Vport context of the Ethernet port associated with the subscriber:
CLI syntax:
config>port>ethernet>access>egress>vport>host-match dest string create
If a specific subscriber host queue does not have the port-parent option enabled, it is foster-parented to the Vport used by this subscriber and which is based on matching the dest string. If the subscriber could not be matched with a Vport on the egress port, the host queue is not bandwidth controlled and competes for bandwidth directly based on its own PIR and CIR parameters.
By default, a subscriber host queue with the port-parent option enabled is scheduled within the context of the port’s port scheduler policy. To indicate the option to schedule the queue in the context of a port scheduler policy associated with a Vport, the user enters the following command in SLA profile used by the subscriber host:
CLI syntax:
config>subscr-mgmt>sla-profile>egress>qos sap-egress-qos-policy-id vport-scheduler
This command is persistent meaning that the user can re-enter the qos node without specifying the vport-scheduler argument each time and the system remembers it. The user can revert to the default setting without deleting the association of the SLA profile with the SAP egress QoS policy by explicitly re-entering the command with the following new argument:
CLI syntax:
config>subscr-mgmt>sla-profile>egress>qos sap-egress-qos-policy-id port-scheduler