When a subscriber is identified, a special destination string may optionally exist for the subscriber that is typically used to identify the subscriber’s destination aggregation node. This feature applies only to the 7450 ESS and 7950 SR.
On the subscriber’s egress Ethernet port, the default policer-output-queues and other explicitly created queue groups may be configured to represent a destination node by defining the same destination string on the queue group. When the subscriber’s destination string is defined, the system searches the subscriber’s egress port for an egress queue group with the same string defined. If found, it uses that matched queue group instead of the default queue group. If a queue-group matching the string is not found, the subscriber identification event does not fail and the subscriber host is mapped to default policer-output-queues.
The destination node-based queuing model is designed to provide the ability to shape the aggregate subscriber output to a destination aggregation node based on a queue group created for the specific purpose. On the queue group, a scheduling-policy is applied that defines the wanted virtual scheduling behavior of the queues and aggregate maximum rate of the queue group. The destination string matching function could be used to represent any arbitrary downstream bandwidth limit, not just an aggregation node. If the destination string is not present (null value), the default policer egress queue group ('policer-output-queues') on the subscriber’s port is used.