All IP data packets flowing through the BQN are assigned to a subscriber and to a flow. The BQN acts on traffic grouped per subscriber and per flow.

• A subscriber is an IPv4 address on the access side, or any IPv6 address from the same /64 subnet on the access side. See Subscriber Identification section for more details.
•  A flow is a TCP connection, or a UDP flow, or a flow with another protocol (e.g.  ICMP ping).A subscriber can have many flows at the same time.

To decide in a flexible way which functionalities to apply, the BQN uses policies. Policies define the actions to perform on the traffic (e.g., TCP Optimization or rate limitation), along with action parameters (e.g., a speed limit). There are three kinds of policies: flow policies, rate policies, and monitoring policies. Every flow is assigned a subscriber flow policy, while every subscriber is assigned a rate policy and a monitoring policy.

A data packet will receive all the functionalities specified in the flow policy for the flow it belongs to, and all the functionalities specified in the rate policy and the monitoring policy for the subscriber it belongs to. In this way, it is possible to specify different functionalities to all the flows of a subscriber, or just to certain flows of that subscriber.

Through flow policies we specify the following functionalities:

• TCP Optimization (TCPO).
• Limit the speed of all the subscriber flows matching an application definition (shaping). It is a per-subscriber limit, applying to the sum of the speed of all the subscriber flows assigned to the flow policy.
• Completely blocking of specific traffic types.
• Blocking only incoming connections from Internet of specific traffic types.

Through rate policies, we specify the following functionalities:

• Limit the total network speed of a subscriber.

Through monitoring policies, we specify the following functionalities:

• The amount of sampling when collecting DPI information for a subscriber.

The rate policy of a subscriber can be assigned from an external system (via RADIUS or via our REST API) or using profiles and rules. Flow policies and monitoring policies, are assigned using profiles and rules:

• ‍Profiles classify the traffic according to some criteria (for example, an access profile identifies all the traffic from subscribers within a set of IP address ranges).

• Rules relate policies and profiles. For example, a rule may specify that some specific access profile is limited by a rate policy, i.e., that subscribers whose IP address are in some subnet will have a specific rate limit.