Edge device and method for interconnecting SS7 signaling points (SPs) using edge device

• US 20050238036A1
• Filed: 05/12/2005
• Published: 10/27/2005
• Est. Priority Date: 12/04/1998
• Status: Active Grant

• Current Assignee: Tekelec Global, Inc. (Oracle Corporation)
• Original Assignee: Tekelec
• Inventors: Ravishankar, Venkataramaiah, Miller, Paul Andrew
• Granted Patent: US 7,522,580 B2
• Time in Patent Office: Days
• US Class Current: 370/401
• CPC Class Codes: H04L 69/08 Protocols for interworking; Protocol conversion
• CPC Class Codes: H04L 69/085 specially adapted for interworking of IP-based networks with other networks
• CPC Class Codes: H04L 69/16 Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]
• CPC Class Codes: H04L 69/161 Implementation details of TCP/IP or UDP/IP stack architecture; Specification of modified or new header fields
• CPC Class Codes: H04L 69/169 Special adaptations of TCP, UDP or IP for interworking of IP based networks with other networks protocols for interworking, protocol conversion H04L69/08
• CPC Class Codes: H04L 9/40 Network security protocols
• CPC Class Codes: H04M 7/066 where the auxiliary connection is via an Internet Protocol network interworking of signalling system number 7 (SS7) with Internet Protocol-based session control protocols H04M7/1265, H04M7/127
• CPC Class Codes: H04M 7/1245 where a network other than PSTN/ISDN interconnects two PSTN/ISDN networks
• CPC Class Codes: H04Q 3/0025 Provisions for signalling
• CPC Class Codes: H04Q 3/0029 Provisions for intelligent networking
• CPC Class Codes: H04Q 3/0045 involving hybrid, i.e. a mixture of public and private, or multi-vendor systems
• CPC Class Codes: H04Q 3/005 Personal communication services, e.g. provisions for portability of subscriber numbers

Abstract

Methods and systems for interconnecting SS7 signaling points include connecting an edge device to a plurality of SS7 service switching points using fixed-bandwidth SS7 links. The edge device is connected to an SS7/IP gateway using a variable-bandwidth signaling link. The edge device multiplexes SS7 messages received over the fixed-bandwidth signaling links and transmits the message over the variable-bandwidth signaling link.

Claims

1. A method for interconnecting SS7 signaling points (SPs), the method comprising:

(a) connecting at least one SS7 link interface module of an edge device to a plurality of signaling points (SPs) using a plurality of fixed-bandwidth SS7 signaling links;

(b) connecting an Internet protocol (IP) interface module of the edge device to an IP-capable node using a variable-bandwidth signaling link;

(c) multiplexing signaling messages received from the SPs received over the fixed-bandwidth SS7 signaling links, converting the signaling messages to the IP and transmitting the multiplexed, converted signaling messages to the IP-capable node over the variable-bandwidth signaling link, wherein multiplexing the signaling messages includes using a message transfer part (MTP) level 3 routing function on the at least one SS7 link interface modules to send the signaling messages to the IP interface module; and

(d) at the IP interface module, receiving IP signaling messages over the variable-bandwidth signaling link that are destined for one of the SPs, converting the IP signaling messages to SS7 format, and forwarding the SS7-formatted signaling messages to the at least one SS7 link interface module using an MTP level 3 routing function on the IP interface module.

2. The method of claim 1 wherein converting the signaling messages to IP includes encapsulating the signaling messages in IP datagrams.

3. The method of claim 2 wherein encapsulating the signaling messages in IP datagrams includes encapsulating the messages in transport adapter layer interface packets and encapsulating the transport adapter layer interface packets in transmission control protocol (TCP) segments.

4. The method of claim 3 wherein encapsulating the signaling messages in transport adapter layer interface packets includes adding an application-level sequence number to each transport adapter layer interface packet.

5. The method of claim 2 wherein encapsulating the signaling messages in IP datagrams includes encapsulating the signaling message in user datagram protocol datagrams.

6. The method of claim 1 wherein multiplexing the signaling messages received from the SPs includes, at the MTP level 3 routing function on the at least one SS7 link interface module, performing message transfer part (MTP) routing for the messages to direct all of the signaling messages to the variable-bandwidth signaling link by default.

7. The method of claim 1 wherein multiplexing the signaling messages received from the SPs includes, at the MTP level 3 routing function on the at least one SS7 link interface module, performing MTP routing for the signaling messages to determine whether the messages are directed to locally-connected nodes and, in response to determining that the messages are not directed to locally-directed nodes, routing the messages over the variable-bandwidth signaling link by default.

8. The method of claim 7 comprising, at the MTP level 3 routing function on the at least one SS7 link interface module, in response to determining that the signaling messages are directed to locally-connected nodes, routing the signaling messages to the locally-connected nodes over one of the fixed-bandwidth SS7 signaling links.

9. The method of claim 7 wherein performing MTP routing on the call signaling messages includes, at the MTP level 3 routing function on the at least one SS7 link interface module, extracting destination point code (DPC) values from the call signaling messages and comparing the DPC values to point code values stored in a routing table.

10. The method of claim 1 wherein the IP-capable node comprises an SS7/IP gateway.

11. The method of claim 1 wherein the plurality of SPs comprises a plurality of service switching points (SSPs).

12. The method of claim 11 wherein the plurality of SSPs comprises a plurality of end offices.

13. A method for interconnecting SS7 signaling points (SPs) in a mesh network, the method comprising:

(a) connecting at least one link interface module of a first edge device to first and second SPs in a mesh network using first and second fixed-bandwidth SS7 signaling links;

(b) connecting at least one link interface module of a second edge device to third and fourth SPs in the mesh network using third and fourth fixed-bandwidth SS7 signaling links;

(c) connecting an IP interface module of the first edge device to an IP interface module of the second edge device using a variable-bandwidth signaling link;

(d) multiplexing signaling messages received from the first and second SPs using message transfer part level 3 routing functions resident on the at least one link interface module of the first edge device to send the signaling messages to the IP interface module on the first edge device and, at the IP interface module, encapsulating the signaling messages in IP datagrams and transmitting the IP-encapsulated, multiplexed signaling messages over the variable bandwidth signaling link; and

(e) at the IP interface module on the second edge device, receiving IP-encapsulated, multiplexed signaling messages from the first edge device, converting the IP-encapsulated, multiplexed signaling messages to SS7 format, and forwarding the SS7-formatted signaling messages to one of the at least one interface module of the second edge device using a message transfer part level 3 routing function resident on the IP interface module of the second edge device.

14. The method of claim 13 wherein connecting the IP interface module of the first edge device to the IP interface module of the second edge device includes establishing a TCP/IP connection between the first and second edge devices.

15. The method of claim 13 wherein connecting the at least one link interface module first edge device to the first and second SPs includes connecting the at least one link interface module of the first edge device to the first and second SPs using SS7 access links.

16. The method of claim 13 wherein connecting at least one link interface module of the second edge device to third and fourth SPs includes connecting the at least one interface module of the second edge device to the third and fourth SPs using SS7 access links.

17. An edge device comprising:

(a) at least one SS7 link interface module for receiving SS7 signaling messages from first and second SS7 signaling points over first and second fixed-bandwidth SS7 signaling links;

(b) an Internet protocol (IP) link interface module for receiving the SS7 signaling messages from the at least one SS7 link interface module, for converting the SS7 signaling messages to IP format, and for transmitting the IP-formatted signaling messages over a variable-bandwidth signaling link;

(c) at least one message transfer part (MTP) routing function located on the at least one SS7 link interface module for determining whether the SS7 signaling messages received by the at least one SS7 link interface module are directed to a locally-connected SS7 signaling point, and, in response to determining that the SS7 signaling messages are not directed to a locally-connected SS7 signaling point, for routing the SS7 signaling messages to the IP interface module to be converted to IP format and transmitted over the variable-bandwidth signaling link and thereby multiplexing the SS7 signaling messages received over the first and second fixed-bandwidth signaling links; and

(d) a third MTP level 3 routing function located on the IP interface module for routing inbound SS7 signaling messages extracted from IP datagrams received by the IP link interface module and for routing the inbound SS7 signaling messages to the at least one SS7 link interface module.

18. The edge device of claim 17 wherein the at least one SS7 link interface module includes SS7 layer 2 and layer 3 processes.

19. The edge device of claim 17 wherein the IP link interface module includes an SS7/IP converter process for converting SS7 signaling messages to IP format and forwarding the IP-formatted SS7 signaling messages over the variable-bandwidth signaling link.

20. The edge device of claim 19 wherein the IP link interface module is adapted to forward all outgoing SS7 signaling messages to a first SS7/IP gateway.

21. The edge device of claim 19 wherein the SS7/IP converter is adapted to encapsulate SS7 signaling messages in transport adapter layer interface packets and to encapsulate the transport adapter layer interface packets in IP datagrams.

22. The edge device of claim 21 wherein the SS7/IP converter is adapted to add an application-level sequence numbers to the transport adapter layer interface packets.

23. The edge device of claim 17 wherein the first and second SS7 link interface modules are adapted to receive the SS7 MSUs from a plurality of service switching points (SSPs) over the fixed bandwidth signaling links.

24. The edge device of claim 23 wherein the plurality of SSPs comprises a plurality of end offices.

25. A method for connecting SS7 signaling points (SPs) to an IP-capable node, the method comprising:

(a) locating an edge device proximally to a plurality of SPs;

(b) connecting the edge device to the SPs using a plurality of fixed-bandwidth SS7 signaling links, wherein connecting the edge device to the SPs using fixed bandwidth signaling links includes connecting the SPs to at least one SS7 link interface module in the edge device;

(c) connecting the edge device to an Internet protocol (IP)-capable node located remotely from the edge device using a variable-bandwidth signaling link, wherein connecting the edge device to an IP-capable node includes connecting the edge device to the IP-capable node using an IP interface module within the edge device;

(d) multiplexing SS7 signaling messages received from the SPs, wherein multiplexing the SS7 signaling messages includes using at least one message transfer part layer 3 routing function resident on the at least one link interface module to route the SS7 signaling messages to the IP interface module, and, at the IP interface module, encapsulating the multiplexed signaling messages in IP datagrams and transmitting the multiplexed, encapsulated signaling messages over the variable bandwidth signaling link; and

(e) forwarding SS7 signaling messages extracted from IP datagrams received by the IP interface module to the at least one SS7 link interface modules using a message transfer part layer 3 routing function resident on the IP interface module.

26. The method of claim 25 including provisioning the at least one SS7 link interface module with a simplified message transfer part routing table including routing entries containing linkset addresses corresponding to fixed-bandwidth signaling links for messages directed to locally-connected nodes and a default entry containing a linkset address corresponding to the variable-bandwidth signaling link for messages directed to non-locally-connected nodes.

27. The method of claim 25 including provisioning the at least one of the link interface module with a simplified message transfer part routing table including a single entry for routing all incoming messages to a linkset address corresponding to variable-bandwidth signaling link.

28. The method of claim 25 wherein connecting the edge device to an IP-capable node includes the edge device to an SS7/IP gateway.

29. The method of claim 25 wherein locating the edge device proximally to a plurality of SPs includes locating the edge device proximally to a plurality of service switching points (SSPs) and wherein connecting the edge device to the SP using a fixed-bandwidth SS7 link includes connecting the edge device to the SSPs using a plurality of fixed-bandwidth SS7 signaling links.

30. The method of claim 29 wherein the SSPs comprise end offices.

31. A method for performing network management in a network including at least one fixed-bandwidth SS7 signaling link and at least one variable bandwidth IP signaling link, the method comprising:

(a) determining whether a fixed bandwidth SS7 signaling link is down or congested;

(b) in response to determining that the fixed bandwidth SS7 signaling link is congested, buffering data and instructing a sending node to slow the flow of incoming IP-encapsulated SS7 messages destined for the fixed bandwidth SS7 signaling link; and

(c) in response to determining that the fixed bandwidth SS7 signaling link is down, instructing the sending node to stop the flow of incoming IP-encapsulated SS7 messages destined for the fixed bandwidth SS7 signaling link.

32. The method of claim 31 wherein instructing the sending node to slow the flow of IP-encapsulated SS7 messages includes sending a message to the node over a variable bandwidth signaling link.

33. The method of claim 31 wherein instructing the node to stop the flow of IP-encapsulated SS7 messages includes sending the message over a variable bandwidth signaling link.