General Switch Management Protocol version 3 (GSMPv3) is a generic protocol that allows a switch controller node to establish and maintain connections with one or more nodes to exchange operational information. Several extensions to GSMPv3 exist in the context of broadband aggregation. These extensions were proposed to allow GSMPv3 to be used in a broadband environment as more information is needed to synchronize the control plane between access nodes (such as DSLAMs) and broadband network gateways (such as BRAS).
In the TPSDA framework, nodes fulfill some BRAS functionality, where per subscriber QoS enforcement is one of the most important aspects. To provide accurate per-subscriber QoS enforcement, the network element not only knows about the subscriber profile and its service level agreement but it is aware of the dynamic characteristics of the subscriber access circuit.
The most important parameters in this context are the subscriber-line capacity (DSL sync-rate) and the subscriber's channel viewership status (the actual number of BTV channels received by the subscriber in any point in time). This information can be then used to adjust parameters of aggregate scheduling policy.
Besides, the above-mentioned information, GSMPv3 can convey OAM information between a switch controller and access switch. The node can operate in two roles:
as the intermediate controller
The router terminates a connection from the DSLAM.
as the terminating controller
The router fulfills full the roll of BRAS.
The DSL forum working documents recommends that a dedicated Layer 2 path (such as, a VLAN in an Ethernet aggregation network) is used for this communication to provide a specific level of security. The actual connection between DSLAM and BRAS is established at TCP level, and then individual messages are transported.