Policy and charging control method and system for multi-PDN connections of single APN

A system for performing policy and charging control for establishing multiple packet data network (PDN) connections to a single access point name (APN), comprising:

• a destination access gateway which comprises a destination bearer binding and event report function (BBERF), a packet data network gateway which comprises a policy and charging enforcement function (PCEF), a visited network device which comprises a visited policy and charging rule function (PCRF), and a home network device which comprises a home PCRF;
• wherein:
• after at least one PDN connection with at least one corresponding subsession of a S9 session is established for said APN in a roaming scenario, when BBERF relocation occurs,
• said destination BBERF is configured to:
• send a gateway control session establishment request message to the visited PCRF to request establishing a gateway control session, wherein a new packet data network connection identifier (PDN Connection ID) is carried in said gateway control session establishment request message;
• and
• said visited PCRF is configured to:
• receive the gateway control session establishment request message sent by said destination BBERF, and associate the gateway control session with said subsession of said S9 session that was associated with a Gx session in the previously established PDN connection to the same APN through an indication of internet protocol connectivity access network (IP-CAN) session modification message according to said new PDN Connection ID;
• wherein, in a home routed roaming scenario, said PCEF is located in a home network,
• said PCEF is configured to:
• send the indication of IP-CAN session modification message to said home PCRF, wherein said new PDN Connection ID is carried in said indication of IP-CAN session modification message;
• said home PCRF is configured to:
• after receiving said indication of IP-CAN session modification message sent by said PCEF, send an S9 session and rule provision message to said visited PCRF, and said new PDN Connection ID is carried in said subsession of said S9 session associated with the Gx session modified by said indication of IP-CAN session modification message;
• and
• said visited PCRF is further configured to:
• receive said S9 session and rule provision message sent by said home PCRF, and associate said gateway control session with said subsession of said S9 session according to said new PDN Connection ID after receiving said S9 session and rule provision message;
• or
• wherein, in a local breakout roaming scenario, the PCEF is located in a visited network,
• said PCEF is configured to:
• send the indication of IP-CAN session modification message to said visited PCRF, wherein said new PDN Connection ID is carried in said indication of IP-CAN session modification message;
• and
• said visited PCRF is further configured to:
• receive said indication of IP-CAN session modification message sent by said PCEF, and associate the gateway control session established according to said gateway control session establishment request message with said Gx session modified by the indication of IP-CAN session modification message according to said new PDN Connection ID carried in said indication of IP-CAN session modification message;
• and associate said gateway control session with said subsession of said S9 session associated with said Gx session.

A network device, comprising a hardware processor which is configured with a visited policy and charging rule function (PCRF), the visited PCRF being configured to:

• after at least one PDN connection with at least one corresponding subsession of a S9 session is established for a single APN in a roaming scenario, when relocation occurs on a bearer binding and event report function (BBERF),
• receive a gateway control session establishment request message sent by a destination bearer binding and event report function (BBERF) for establishing a gateway control session;
• and
• associate the gateway control session with said subsession of said S9 session that was associated with a Gx session in the previously established PDN connection to the same APN through an indication of internet protocol connectivity access network (IP-CAN) session modification message according to a new packet data network connection identifier (PDN Connection ID) carried in said gateway control session establishment request message;
• wherein in a home routed roaming scenario, a policy and charging enforcement function (PCEF) is located in a home network, and said visited PCRF associates the gateway control session with said subsession of said S9 session that was associated with the Gx session in the previously established PDN connection to the same APN through the indication of IP-CAN session modification message by a following process of:
• the home PCEF sending the indication of IP-CAN session modification message to a home PCRF, wherein said new PDN Connection ID is carried in said indication of IP-CAN session modification message;
• said home PCRF sending an S9 session and rule provision message to said visited PCRF after receiving said indication of IP-CAN session modification message, and said new PDN Connection ID is carried in said subsession of said S9 session associated with the Gx session modified by said indication of IP-CAN session modification message;
• and
• said visited PCRF associating said gateway control session with said subsession of said S9 session according to said new PDN Connection ID after receiving said S9 session and rule provision message;
• or
• wherein in a local breakout roaming scenario, the PCEF is located in a visited network, the visited PCEF sends the indication of IP-CAN session modification message to said visited PCRF, and said new PDN Connection ID is carried in said indication of IP-CAN session modification message, and said visited PCRF associates the gateway control session with said subsession of said S9 session that was associated with the Gx session in the previously established PDN connection to the same APN through the indication of IP-CAN session modification message by a following process of:
• said visited PCRF associating the gateway control session with said Gx session modified by said indication of IP-CAN session modification message according to said new PDN Connection ID;
• and
• said visited PCRF associating said gateway control session with said subsession of said S9 session associated with said Gx session.