IP ADDRESS VERSION INTERWORKING IN COMMUNICATION NETWORKS

• US 20120082158A1
• Filed: 10/04/2010
• Published: 04/05/2012
• Est. Priority Date: 10/04/2010
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: AGARWAL, Kaitki, REDDY, Naveen
• Granted Patent: US 8,811,393 B2
• Time in Patent Office: Days
• US Class Current: 370/389
• CPC Class Codes: H04L 65/1016 IP multimedia subsystem [IMS]
• CPC Class Codes: H04L 65/1104 Session initiation protocol [SIP]
• CPC Class Codes: H04L 69/08 Protocols for interworking; Protocol conversion
• CPC Class Codes: H04L 69/167 Adaptation for transition between two IP versions, e.g. between IPv4 and IPv6 translation of Internet protocol [IP] addresses H04L61/2503
• CPC Class Codes: H04W 80/045 involving different protocol versions, e.g. MIPv4 and MIPv6

Abstract

Systems and methods are provided for supporting IPv4-IPv6 interworking of SIP messages in wireless networks and IMS networks. The interworking can be provided to smooth migration to an all-IPv6 IMS network by allowing the use and support of existing legacy IPv4 infrastructure. This functionality may be provided by a call session control function (CSCF) interposed between a user equipment (UE) and an IMS core network with interworking functionality or an interworking module. This device serves as a back-to-back user agent (B2BUA), allocates IP addresses from a pool, performs next-hop route protocol discovery, and maintains and stores information within the gateway as well as interworking and rewriting IP addresses within network messages, while proxying and maintaining sessions between the UE and the IMS core network. This allows for faster call setup, reduced capex/opex, improved debuggability, increased capacity and subscriber density by call processing distribution, and better user experience.

Claims

1. An apparatus comprising:

a processor;

a memory coupled to the processor configured for storing state information relating to a session between a mobile node and a remote endpoint on an IP Multimedia Subsystem (IMS) network;

a first network interface for communicating with the mobile node via a radio access network;

a second network interface for communicating with the IMS network;

a session module configured to receive packet data units (PDUs) from the first network interface and the second network interface and operable to use an inbound identifier and an outbound identifier with the session; and

an interworking module coupled to the first network interface and the second network interface that is operable to interwork between session initiation protocol (SIP) messages that use an IPv4 protocol and SIP messages that use an IPv6 protocol, and is operable to use one of the inbound identifier and the outbound identifier to match an incoming SIP message to the session.

2. The CSCF of claim 1, wherein the interworking module is operable to allocate IP addresses from a pool of IP addresses.

3. The CSCF of claim 2, wherein the CSCF is operable to perform network address translation (NAT) using the pool of IP addresses.

4. The CSCF of claim 1, wherein the CSCF is operable to use the inbound identifier and the outbound identifier to identify a process instance that is currently handling the session.

5. The CSCF of claim 1, wherein the inbound identifier and the outbound identifier are stored in the outgoing SIP message in a Record-Route header in conjunction with a custom parameter.

6. The CSCF of claim 1, wherein the state information is stored in a memory located at a process instance.

7. The CSCF of claim 1, wherein IPv4 packets are received at a first access service at the CSCF, IPv6 packets are received at a second access service at the CSCF, and the first access service forwards SIP messages to the second access service before interworking is performed.

8. The CSCF of claim 1, wherein the interworking module determines whether to perform interworking using the availability of a domain name system (DNS) AAAA record for a next-hop routing address.

9. The CSCF of claim 1, wherein the CSCF is a serving CSCF, the mobile node is a user equipment (UE), and the radio access network is an evolved universal terrestrial radio access network (EUTRAN).

10. A method comprising:

receiving a SIP message at a call session control function (CSCF) from a mobile device for communication on an IP multimedia subsystem (IMS) network using a first IP protocol version;

determining, at the session controller, whether to perform interworking of the mobility message before forwarding the mobility message;

interworking the mobility message at the session controller from the first IP protocol version to a second IP protocol version by substituting, in the mobility message, addresses that conform to the second protocol version;

populating a mapping table with an inbound call leg identifier and an outbound call leg identifier and session information;

storing the inbound call leg identifier and the outbound call leg identifier in the mobility message; and

forwarding the mobility message from the session controller to a destination using the second IP protocol version.

11. The method of claim 10, further comprising determining whether to perform interworking of the mobility message based on a previously-set flag stored at the session controller.

12. The method of claim 10, further comprising determining whether to perform interworking of the mobility message based on the inbound call leg identifier and the outbound call leg identifier previously stored in the mobility message at the session controller.

13. The method of claim 10, wherein the session controller uses the availability of a domain name system (DNS) AAAA record to determine whether to perform interworking of the mobility message.

14. The method of claim 10, wherein the mobility message is an SIP message and the session controller is a serving-call session control function (CSCF).

15. Logic encoded in one or more non-transient media that includes code for execution and when executed by a processor is operable to perform operations comprising:

receiving a message using a first protocol at a first access service at a call session control function (CSCF) connected to an IP multimedia subsystem (IMS) network and to a mobile device over a radio access network;

forwarding the message to a second access service at the CSCF;

interworking the message from the first protocol to a second protocol at the CSCF using state information relating to a session in a memory at the CSCF; and

sending the message from the second access service using the second protocol.

16. The logic of claim 15, the operations further comprising interworking the message from the first protocol to the second protocol at the second access service.

17. The logic of claim 15, the operations further comprising using the state information to identify pre-interworking IP addresses.

18. The logic of claim 15, the operations further comprising setting a per-session flag to indicate whether interworking is needed for a session.

19. The logic of claim 15, the operations further comprising allocating an IP address from a predetermined pool of addresses.

20. The logic of claim 15, wherein the first protocol is IPv4 and the second protocol is IPv6, and wherein the CSCF is a serving-call session control function (S-CSCF), and wherein the state information is a custom parameter in an SIP Record-Route header.