About Policy Management Service Flows

The MPE device establishes service flows between subscribers and the application servers that provide multimedia services.

A service flow is activated only after the contents of its QoS request are examined and approved by the MPE device. If approved, the request is forwarded to the intended destination network node.

As illustrated in Figure 1, when a subscriber wishes to make a 3G-LTE wireless call, the following actions occur:

1. Subscriber powers on the user equipment (UE) for example, a cell phone.
2. The UE radio pings for the nearest cell tower to which it can connect.
3. The UE identifies itself to the network and attaches to the network.
4. The subscriber calls a phone number.
5. The radio tower's base station (BS) equipment (node B for 3G networks) [part of the base station subsystem (BSS) that handles telecommunication traffic] receives the signal and routes it to the mobile switching center (MSC) for validation of the subscriber account.
6. The MSC routes the phone call and connects to the Mobility Management Entity (MME) for the public switched telephone network (PSTN).
7. The MME authenticates the UE/subscriber to the Home Subscriber Server (HSS).
8. The MME chooses a Serving Gateway (SGW) or Packet Data Network Gateway (PGW) for session binding.
9. The PGW authorizes the UE to access the Public Land Mobile Network (PLMN) via an Access Point Name (APN) and enforces UE roaming restrictions (if any).
10. Using the Gx interface, the PGW connects with Policy Management:
    1. The PGW connects with either its associated MPE device or MRA device (if present).
    2. The MPE device examines the QoS request before it gets to the network element and processes the request against the policy rules within its policy repository.
    3. The MPE device then makes a decision based on the defined policy rules to accept or reject the request.
    4. Depending on the decision made, the MPE device performs one of the following actions:
       • Accepts the QoS request and forwards it to the network element, where the required network resources are provisioned, allowing the service flow for IP-streaming to be admitted and activated.
       • Rejects the QoS request, in which case an error message is sent back to the application and no service flow is established.
         Note: When provisioned resources are no longer required and deleted, the network resources are recovered for use elsewhere.