Policy co-ordination in a communications network
In order to address the problem of allowing a GGSN 16 of a UMTS core network to work towards multiple Policy Control Functions (PCFs) 17 co-located with P-CSCF nodes 18 using the COPS protocol, a policy control function coordinator (PCF-C) 15 is implemented between the GGSN 16 and the P-CSCF 18. A single COPS connection is established between the GGSN 16 and the PCF-C 15 , whilst a COPS connection is established between the PCF-C 15 and each of the P-CSCF nodes 18 . Decisions made at the PCFs 17 are routed to the GGSN 16 via the PCF-C 17 , and responses generated at the GGSN 16 are routed to the appropriate PCFs 17 via the GGSN 17 . This architecture avoids conflicts which might otherwise arise with the COPS protocol.
1. A method of notifying a policy enforcement point (PEP) node of policies and/or policy decisions made at a plurality of policy decision point (PDP) nodes, the PEP and the plurality of PDP nodes being arranged to communicate with one another via an IP network using the Common Open Policy Service, COPS, protocol, the method comprising:
at said PEP node, establishing a virtual policy enforcement point for each of the plurality of PDP nodes;
establishing a COPS connection between each of the virtual policy enforcement points and corresponding ones of the plurality of PDP nodes; and
sending decisions and decision responses between the virtual policy enforcement points and the corresponding ones of the plurality of PDP nodes over the respective COPS connections.
2. The method of claim 1 , wherein said policy enforcement point node is a GGSN of a data network within a telecommunications network and said second policy decision point nodes are P-CSCF nodes of an IP Multimedia Core Network Subsystem (IMS), the P-CSCF nodes each implementing a Policy Control Function for the GGSN.
3. The method of claim 1 further comprising;
establishing a coordination node between policy enforcement points in the PEP node and each of the plurality of PDP nodes;
sending decisions from the PDP nodes to the coordination node over the respective COPS connections and, at the coordination node, recording sources of the decisions and forwarding the decisions to the PEP node over the COPS connections; and
sending responses to decisions from the PEP node to the coordination node over the respective COPS connections and at the coordination node identifying source PDP nodes of the decisions based upon the recorded sources and forwarding the responses to the respective PDP nodes over the respective COPS connections.
4. The method of claim 3 wherein said coordination node records the identity of an originating PDP node for each decision received by said coordination node and routes responses received from the PEP node according to the recorded information.
5. The method of claim 3 wherein said PEP node includes a Gateway General Packet Radio Service Support Node (GGSN).
6. The method of claim 5 wherein said plurality of second nodes include Call State Control Functions (CSCFs).
7. A Gateway Support Node for use in a packet switched network of a mobile telecommunications network, the Node comprising:
first input/output means for coupling to said packet switched network:
second input/output means for coupling to an IP network to which a plurality of policy decision point nodes are coupled; and
one or more processors coupled to the first and second input/output means for implementing a plurality of virtual Gateway Support Node functions within the Gateway Support Node, for establishing a COPS connection between each of the plurality of virtual Gateway Support Node functions and the corresponding policy decision point nodes and for exchanging decisions and decision responses with the corresponding policy decision point nodes over the respective COPS connections.
8. The Gateway Support Node of claim 7 , the node being a GPRS Gateway Support Node for use in providing a GPRS packet switched service.