Patent Application
20070036325
1. Field of the Invention
The present invention relates to a signaling system 7 (SS7) network.
2. Background Art
A signaling system 7 (SS7) network is used for performing out-of-band signaling for switched voice networks. A SS7 network is a separate network laid over switched voice networks such as the public switched telephone network (PSTN) and the public land mobile network (PLMN). A SS7 network is a private network required to route telephone calls that connect telephone users in different central offices of switched voice networks. A SS7 network is also the platform upon which other telecommunications services such as local number portability (LNP) are transported.
A SS7 network includes interconnected signaling points such as signal transfer points (STPs), service switching points (SSPs), and service control points (SCPs). STPs route queries and responses between central offices of a switched voice network and the SCPs. The SCPs have databases which contain call routing instructions and also contain services such as network-based voice mail. The SSPs enable the central offices (i.e., the central office SSPs) to communicate with the databases in the SCPs.
Dedicated wireline SS7 links interconnect the signaling points in a SS7 network. Some pairs of signaling points are interconnected by redundant (i.e., two or more) wireline SS7 links. Redundant wireline SS7 links are provided between two signaling points to ensure that at least one of the wireline SS7 links between these signaling points is operable in the event that any of the other wireline SS7 links between these signaling points fail.
For example, a given central office SSP has two to four wireline SS7 links which are diversely routed through different transport facilities to another signaling point. The diversely routed wireline SS7 links provide diverse signaling communications paths between the central office SSP and the other signaling point. Multiple diverse signaling communications paths between the central office SSP and the other signaling point are likely not to fail at the same time thereby ensuring that a signaling communications path between the central office SSP and the other signaling point is available at all times. If all of these communications paths between the central office SSP and the other signaling point should fail at the same time, then this results in the central office being isolated from the other signaling point (i.e., no inter-switch calls can be placed or received by the central office).
Sometimes the wireline SS7 links between two signaling points are not diversely routed between different communications paths but are instead transported over the same transport facility. For example, a central office SSP and another signaling point may be interconnected by multiple wireline SS7 links routed through the same transport facility. If the transport facility fails, then this results in the central office being isolated from the other signaling point.
A central office which is isolated from other signaling points and is thereby prevented from communicating SS7 messages to the other signaling points disrupts telephone calls handled by the central office. Such outages result in the communications provider responsible for the central office being fined by the FCC.
The present invention is pointed out with particularity in the appended claims. However, other features of the present invention will become more apparent and the present invention will be best understood by referring to the following detailed description in conjunction with the accompanying drawings in which:
The present invention provides a signaling system 7 (SS7) network having wireline and failover wireless SS7 links for a communication network having a switched voice network. The SS7 network in accordance with the present invention overlays the switched voice network. As such, the communications network includes the switched voice network overlaid by the SS7 network in accordance with the present invention. The SS7 network in accordance with the present invention provides a failover connectivity model which uses available wireless communications data networks to provide wireless SS7 signaling backup for failed wireline SS7 links. As a result, the number of signaling point isolations due to wireline SS7 link failures is mitigated. Consequently, the number of central office (i.e., switch) isolations due to wireline SS7 link failures is also mitigated.
The SS7 network in accordance with the present invention provisions for a wireless data network based backup service for wireline SS7 links. The SS7 network in accordance with the present invention employs a wireless data network such as the current WiFi 802.11g wireless data network or the emerging WiMax 802.16 wireless data network for providing failover wireless SS7 link connectivity between signaling points. As such, signaling points of the SS7 network in accordance with the present invention are interconnected by wireline and wireless SS7 links. The wireless SS7 link connectivity between two signaling points takes the place of the wireline SS7 link connectivity between the two signaling points upon the wireline SS7 link connectivity failing. For example, upon the wireline SS7 link connectivity between a central office SSP and an STP failing, the wireless data network provides wireless SS7 link connectivity between the central office SSP and the STP. As a result, the central office is not isolated because of the wireline SS7 link connectivity failure and the telephone calls handled by the central office remain uninterrupted.
In the SS7 network in accordance with the present invention, a telecommunications node such as a central office automatically switches over to a “n+1” SS7 link (“n”=wireline SS7 link set; “n +1”=the wireless SS7 link) using current SS7 link priority functions once the node determines that its primary SS7 communications paths (i.e., the wireline SS7 link set) are unavailable. Upon the n+1 SS7 link (i.e., the wireless SS7 link) between the node and another signaling point (such as an STP) being activated, the wireless SS7 link terminates into a mediation device that converts/encapsulates the SS7 message (which was generated in the straight SS7 protocol used by wireline SS7 links for transporting SS7 messages between signaling points) into an SS7 IP based transport protocol for wireless delivery from the node to the STP where, depending on the STP type, the message may or may not have to be mediated back to the straight SS7 protocol.
The advantages associated with the SS7 network in accordance with the present invention are numerous. For example, the SS7 network in accordance with the present invention makes switched voice networks more dependable. The SS7 network in accordance with the present invention requires relatively small capital investment, utilizes all of the benefits of existing SS7 networks, and improves reliability of switched voice networks all while moving the switched voice networks towards an IP based switching environment.
Referring now to
SS7 network 14 provides SS7 functionality to switched voice network 12. For example, SS7 network 14 communicates SS7 signals to central offices 20 and 22 in order for these central offices to establish switch connection 21 through one another for connecting telephone 26 and telephone 30. That is, SS7 network 14 communicates SS7 signals to central offices 20 and 22 in order to control, route, establish, and maintain a telephone call between telephones 26 and 30 via these central offices. SS7 network 14 includes signaling points such as signal transfer points (STPs) 36 and 38, service control point (SCP) 40, and service switching points (SSPs) which are operable for communicating SS7 signals. The signaling points are interconnected with one another in order to communicate SS7 signals to one another. The SSPs are respectively part of central offices 20, 22, and 24. As such, central office SSPs 20, 22, and 24 communicate SS7 signals with SCP 40 via STPs 36 and 38 in order to control, route, establish, and maintain telephone calls between telephones 26, 28, 30, 32, and 34 via the central offices.
The signaling points of SS7 network 14 are interconnected with one another by a wireline SS7 link set 16 and a wireless SS7 link 18. A wireline SS7 link set 16 interconnecting two signaling points of SS7 network 14 includes two or more wireline SS7 links which are routed between these signaling points via a single transport facility or via different transport facilities. (Alternatively, a single wireline SS7 link 16 interconnects two signaling points of SS7 network 14.)
In accordance with the present invention, a wireless SS7 link 18 interconnecting two signaling points provides a failover SS7 link between these signaling points during the time that the wireline SS7 link set 16 between these signaling points fails. During failure of the wireline SS7 link set 16 between these signaling points, none of the wireline SS7 links in the link set are available for communicating SS7 signals between these signaling points. During this time, in accordance with the present invention, SS7 signals are communicated between these signaling points via the wireless SS7 link 18 interconnecting these signaling points. As soon as one or more of the wireline SS7 links of wireline SS7 link set 16 interconnecting these signaling points is recovered then SS7 signals are communicated between these signaling points via one of the recovered wireline SS7 links instead of being communicated between these signaling points via the wireless SS7 link 18 interconnecting these signaling points.
For example, central office SSP 20 and STP 36 are interconnected by a wireline SS7 link 16a and a wireless SS7 link 18a. Under normal operational conditions, central office SSP 20 communicates SS7 signals with STP 36 via wireline SS7 link 16a in order to communicate SS7 signals with SCP 40. As such, central office 20 is not isolated from communicating SS7 signals with the signaling points of SS7 network 14 under normal operating conditions. However, SS7 signals cannot be communicated over wireline SS7 link 16a under abnormal operating conditions when wireline SS7 link 16a fails. As such, during this time, central office SSP 20 will be isolated from communicating SS7 signals with other signaling points if there are no other functional SS7 links available for the central office SSP 20 to use to communicate SS7 signals.
In accordance with the present invention, wireless SS7 link 18a effectively steps in for and temporarily replaces wireline SS7 link 16a while the wireline SS7 link has failed to thereby prevent central office SSP 20 from being isolated from communicating SS7 signals to/from the other signaling points in SS7 network 14. As soon as wireline SS7 link 16a is operational after its failure, then wireline SS7 link 16a is reenabled in place of wireless SS7 link 18a to thereby communicate SS7 signals between central office SSP 20 and the other signaling points in SS7 network 14.
As another example, a wireline SS7 link 16b and a wireless SS7 link 18b interconnect STP 36 and SCP 40. STP 36 and SCP 40 communicate SS7 signals with one another via wireline SS7 link 16b while the wireline SS7 link is functional. In accordance with the present invention, STP 36 and SCP 40 communicate SS7 signals with one another via wireless SS7 link 18b while wireline SS7 link 16b is not functional. As such, STP 36 and SCP 40 are not isolated from communicating SS7 signals with one another during all times (i.e., during the time that wireline SS7 link 16b is functional and during the time that the wireline SS7 link is not functional).
Referring now to
Wireless SS7 links 18c and 18d are part of a wireless data network such as a WiFi 802.11g wireless data network or a WiMax 802.16 wireless data network. For instance, as shown in
Central office SSP 22 and STPs 36 and 38 communicate SS7 signals between one another via wireline SS7 links 16c and 16d using a conventional SS7 protocol. Central office SSP 22 and STPs 36 and 38 communicate SS7 signals between one another via wireless SS7 links 18c and 18d using an SS7oIP based transport protocol. To this end, mediators 42, 46, and 48 convert/encapsulate SS7 signals generated in accordance with the conventional SS7 protocol to the SS7 IP based transport protocol for wireless delivery over wireless SS7 links 18c and 18d. Similarly, mediators 42, 46, and 48 de-convert/de-encapsulate SS7 signals generated in accordance with the SS7oIP based transport protocol to the conventional SS7 protocol.
For example, central office SSP 22 generates a SS7 signal using the conventional SS7 protocol for receipt by STP 36 via wireless SS7 link 18c. Mediator 42 receives the SS7 signal and then converts/encapsulates the SS7 signal to the SS7oIP based transport protocol. Antenna 44 then transmits the converted/encapsulated SS7 signal to antenna 48 for receipt by STP 36. Mediator 46 receives the converted/encapsulated SS7 signal from antenna 48 and then de-converts/de-encapsulates the SS7 signal back to the conventional SS7 protocol. Mediator 46 then provides the SS7 signal set in accordance with the conventional SS7 protocol to STP 36. This process is then repeated when STP 36 communicates a SS7 signal back to central office SSP 22 via wireless SS7 link 18c.
Accordingly, as shown in
Referring now to
MTSO 64 wirelessly connects with cellular phones serviced by MTSO 64 via base stations (i.e., cellular antennas). For instance, cellular phone 66 wirelessly connects with MTSO 64 via a base station 68, and cellular phone 70 wirelessly connects with MTSO 64 via a base station 72. MTSO 64 establishes a switch connection within itself to connect cellular phones 66 and 70 to one another when users of these cellular phones call one another. MTSO 64 establishes switch connections with central offices of the PSTN such as central offices 20, 22, and 24 in order to connect together cellular phones with telephones or with other cellular phones. For example, MTSO 64 and central office 24 establish a switch connection 65 through one another in order to connect together cellular phone 66 (serviced by MTSO 64) and telephone 32 (serviced by central office 24).
SS7 network 14 provides SS7 functionality to both switched voice networks 12 and 62. For example, SS7 network 14 communicates SS7 signals to MTSO 64 for the MTSO to use in order to establish cellular telephone calls between cellular phones serviced by the MTSO and other cellular phones serviced by other MTSOs. Likewise, SS7 network 14 communicates SS7 signals to central office 24 and MTSO 64 in order for these offices to establish switch connection 65 through one another for connecting telephone 32 and cellular phone 66. To this end, an SSP of SS7 network 14 is part of MTSO 64 just like other SSPs of the SS7 network are respectively part of central offices 20, 22, and 24. As such, MTSO SSP 64 communicates SS7 signals with SCP 40 via STP 38 just like central office SSPs 20, 22, and 24 communicate SS7 signals with SCP 40 via STPs 36 and 38 in order to control, route, and maintain calls between the telephones and cellular phones of switched voice networks 12 and 62.
MTSO SSP 64 is connected to STP 38 by a wireline SS7 link set 16 and a wireless SS7 link 18 in order to communicate SS7 signals with the signaling points of SS7 network 14. Wireless SS7 link 18 interconnecting MTSO SSP 64 to STP 38 provides a failover SS7 link between these signaling points during the time that wireline SS7 link set 16 between these signaling points fails. As soon as a wireline SS7 link of wireline SS7 link set 16 interconnecting MTSO SSP 64 and STP 38 has been recovered then SS7 signals are communicated between these signaling points via the recovered wireline SS7 link. As such, MTSO SSP 64 is not isolated from communicating SS7 signals with the other signaling points of SS7 network 14 while wireline SS7 link set 16 associated with the MTSO SSP is in a failure condition.
Referring now to
The signaling point further includes a controller 86 and a SS7 signal transceiver 88 (in the case of central office SSP 22, SS7 signal transceiver 88 is part of the SSP). SS7 signal transceiver 88 generates SS7 signals using the conventional SS7 protocol for transmission to other signaling points via ports 80 and 82. Likewise, SS7 signal transceiver 88 receives SS7 signals generated in accordance with the conventional SS7 protocol received from other signaling points via ports 80 and 82. Controller 86 switches SS7 signal transceiver 88 to connect with one of ports 80 and 82 at any one time depending on which of wireline and wireless SS7 links 16 and 18 are to be used for communicating SS7 signals to/from central office SSP 22. For instance, controller 86 connects SS7 signal transceiver 88 to wireline SS7 input/output port 80 when SS7 signals are to be communicated over wireline SS7 link(s) 16. Likewise, controller 86 connects SS7 signal transceiver 88 to wireless SS7 input/output port 82 when SS7 signals are to be communicated over wireless SS7 link 18. As such, controller 86 connects SS7 signal transceiver 88 to one of wireline and wireless SS7 links 16 and 18 at any one time depending on the operational status of wireline SS7 link(s) 16 as detected by detector 84.
Referring now to
Upon the failure of wireline SS7 link 16 being detected, the two signaling points are switched over to a wireless SS7 link 18 interconnecting these signaling points as shown in block 96. That is, wireless SS7 link 18 temporarily takes the place of wireline SS7 link 16 upon the wireline SS7 link failing. The two signaling points then communicate SS7 signals over wireless SS7 link 18 as shown in block 98. While SS7 signals are being communicated over wireless SS7 link 18, the SS7 signaling operation further includes detecting the operational status of wireline SS7 link 16 to determine if the wireline SS7 link has been restored as shown in block 100. Upon restoration of wireline SS7 link 16, the two signaling points are switched back to the wireline SS7 link as shown in block 102. That is, wireline SS7 link 16 retakes its place and wireless SS7 link is regulated to its backup role. The SS7 signaling operation then continues with SS7 signals being communicated between the two signaling points over wireline SS7 link 16 as shown in block 92.
Referring now to
Computer system 600 may include a processor 602 (e.g., a central processing unit (CPU), a graphics processing unit (GPU), or both), a main memory 604 and a static memory 606, which communicate with each other via a bus 608. Computer system 600 may further include a video display unit 610 (e.g., a liquid crystal display (LCD), a flat panel, a solid state display, or a cathode ray tube (CRT)). Computer system 600 may include an input device 612 (e.g., a keyboard), a cursor control device 614 (e.g., a mouse), a disk drive unit 616, a signal generation device 618 (e.g., a speaker or remote control) and a network interface device 620.
Disk drive unit 616 may include a machine-readable medium 622 on which is stored one or more sets of instructions (e.g., software 624) embodying any one or more of the methodologies or functions described herein, including those methods illustrated in herein above. Instructions 624 may also reside, completely or at least partially, within main memory 604, static memory 606, and/or within processor 602 during execution thereof by computer system 600. Main memory 604 and processor 602 also may constitute machine-readable media. Dedicated hardware implementations including, but not limited to, application specific integrated circuits, programmable logic arrays and other hardware devices can likewise be constructed to implement the methods described herein. Applications that may include the apparatus and systems of various embodiments broadly include a variety of electronic and computer systems. Some embodiments implement functions in two or more specific interconnected hardware modules or devices with related control and data signals communicated between and through the modules, or as portions of an application-specific integrated circuit. Thus, the example system is applicable to software, firmware, and hardware implementations.
In accordance with various embodiments of the present invention, the methods described herein are intended for operation as software programs running on a computer processor. Furthermore, software implementations can include, but not limited to, distributed processing or component/object distributed processing, parallel processing, or virtual machine processing can also be constructed to implement the methods described herein.
The present invention contemplates a machine readable medium containing instructions 624, or that which receives and executes instructions 624 from a propagated signal so that a device connected to a network environment 626 can send or receive voice, video or data, and to communicate over the network 626 using the instructions 624. Instructions 624 may further be transmitted or received over a network 626 via network interface device 620.
While machine-readable medium 622 is shown in an example embodiment to be a single medium, the term “machine-readable medium” should be taken to include a single medium or multiple media (e.g., a centralized or distributed database, and/or associated caches and servers) that store the one or more sets of instructions. The term “machine-readable medium” shall also be taken to include any medium that is capable of storing, encoding or carrying a set of instructions for execution by the machine and that cause the machine to perform any one or more of the methodologies of the present invention. The term “machine-readable medium” shall accordingly be taken to include, but not be limited to: solid-state memories such as a memory card or other package that houses one or more read-only (non-volatile) memories, random access memories, or other re-writable (volatile) memories; magneto-optical or optical medium such as a disk or tape; and carrier wave signals such as a signal embodying computer instructions in a transmission medium; and/or a digital file attachment to e-mail or other self-contained information archive or set of archives is considered a distribution medium equivalent to a tangible storage medium. Accordingly, the present invention is considered to include any one or more of a machine-readable medium or a distribution medium, as listed herein and including art-recognized equivalents and successor media, in which the software implementations herein are stored.
Although the present specification describes components and functions implemented in the embodiments with reference to particular standards and protocols, the present invention is not limited to such standards and protocols. Each of the standards for Internet and other packet switched network transmission (e.g., TCP/IP, UDP/IP, HTML, HTTP) represent examples of the state of the art. Such standards are periodically superseded by faster or more efficient equivalents having essentially the same functions. Accordingly, replacement standards and protocols having the same functions are considered equivalents.
The illustrations of embodiments described herein are intended to provide a general understanding of the structure of various embodiments, and they are not intended to serve as a complete description of all the elements and features of apparatus and systems that might make use of the structures described herein. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. Other embodiments may be utilized and derived therefrom, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. The Figures are merely representational and may not be drawn to scale. Certain proportions thereof may be exaggerated, while others may be minimized. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense.
Such embodiments of the inventive subject matter may be referred to herein, individually and/or collectively, by the term “invention” merely for convenience and without intending to voluntarily limit the scope of this application to any single invention or inventive concept if more than one is in fact disclosed. Thus, although specific embodiments have been illustrated and described herein, it should be appreciated that any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description.
The Abstract of the Disclosure is provided to comply with 37 C.F.R. §1.72(b), requiring an abstract that will allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, it can be seen that various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate embodiment.
