Multiplex communications – Communication techniques for information carried in plural... – Adaptive
Reexamination Certificate
1998-12-21
2001-12-04
Olms, Douglas (Department: 2732)
Multiplex communications
Communication techniques for information carried in plural...
Adaptive
C370S355000, C370S385000
Reexamination Certificate
active
06327267
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention is directed, in general, to communications systems and, more specifically, to systems and methods for routing a message through a signaling network associated with a Public Switched Telephone Network (PSTN), including a method for performing global title routing on an Internet Protocol (IP) address.
BACKGROUND OF THE INVENTION
The world is currently experiencing revolutionary changes in communications systems, brought about by the general availability of access to the Internet as well as the evolution of wireless telephony and Intelligent Network (IN) service enhancements to the Public Switched Telephone Network (PSTN). In particular, interest in Internet Protocol (IP) telephony, or Voice over IP (VoIP), has expanded rapidly as the associated technologies have matured. Improved interoperability is a critical factor to further enhancements in such communications systems, particularly telephony services provided by such systems.
The advent of IP telephony allowing phone calls across packet-switched networks triggered a revolution in the telecommunications industry. Early IP telephony, however, had many limitations that prevented it from becoming a mainstream telephony service. One of the biggest problems was a lack of connectivity between an IP telephony network and the public switched telephone network (PSTN). This led to the development of a gateway that allows IP and PSTN customers to communicate with each other. Differences in the protocols used by the Internet and PSTN, however, have required the development of novel solutions to resolve problems of interoperability between the networks.
Associated with the North American PSTN is a signaling network that employs the Common Channel Signaling System 7 (SS7) to exchange signaling messages between network elements, or “nodes.” Every network must have an addressing scheme, and the SS7 network is no different. Network addresses are required so that a node can exchange signaling messages with nodes to which it does not have a physical signaling link. In SS7, addresses are assigned using a three-level hierarchy. Individual signaling points are identified as belonging to a “cluster” of signaling points. With each cluster, each signaling point is assigned a “member” number. Similarly, a cluster is defined as being part of a “network.” Any node in the American SS7 signaling network can be addressed by a three-level number, or “point code,” defined by its network, cluster and member numbers; each of these numbers is an 8-bit number and can assume values from 0 to 255. A signaling message is transmitted from an originating signaling point, identified by an “origination if point code” (OPC), to a destination signaling point, identified by a “destination point code” (DPC).
Packet-switched networks which use the Internet Protocol (IP), such as the Internet, use an address format that is unlike the three-level point codes used in the North American SS7 signaling network. According to the Internet Protocol Version 4 (IPv4), the addresses of network nodes are always 32 bits in length, and are typically written as a sequence of four numbers representing the decimal value of each of the address bytes. Because of differences in the addressing protocols employed in the PSTN signaling network (e.g. SS7) and other packet-switched networks, such as the Internet, interoperability between the networks can be limited. With the proliferation of IP telephony devices and other Internet applications, however, it is desirable to provide access to certain resources generally only available through the PSTN signaling network. For example, an Internet telephony device could benefit from access to “800” number databases, Service Data Points (SDPs) and Home Location Registers (HLRs) coupled to the PSTN signaling network, as well as Intelligent Network (IN) services available through the PSTN signaling network. Furthermore, the PSTN signaling network might be used when alternate routing of messages is needed, such as in the case of Local Area Network (LAN) or Wide Area Network (WAN) crashes. Because of the proliferation of IP telephony devices and services, and the desire to provide Intelligent Network (IN) services to telephony devices coupled to packet-switched networks, such as the Internet, there is a need in the art for systems and methods for routing a message from a packet-switched network through a signaling network associated with a Public Switched Telephone Network (PSTN).
SUMMARY OF THE INVENTION
To address the above-discussed deficiencies of the prior art, the present invention provides systems and methods for routing a message through a signaling network associated with a public switched telephone network (PSTN), including a method for performing global title routing on an Internet Protocol (IP) address.
In one embodiment, a datagram is received at a first network node. The datagram includes a destination address of a destination node on a signaling network associated with a Public Switched Telephone Network (PSTN); the destination address has an address format associated with a packet-switched network, such as that defined by the Internet Protocol. A message is constructed for transmission from the first network node to a signaling network node; the message includes an address field containing the destination address and a translation type field containing an indicator that the destination address has an address format associated with the packet-switched network. The message is transmitted to the signaling network node, at which the translation type field of the message is examined and, if the indicator in the translation type field corresponds to the address format associated with the packet-switched network, the destination address is translated to a translated destination address corresponding to the destination node of the signaling network; the translated destination address has an address format defined by the signaling network protocol. The second node can be, but is not necessarily, the destination node.
The address type associated with the packet-switched network can be an Internet Protocol (IP) address. Alternatively, the address type may be a Media Access Control (MAC) address. Those skilled in the art will recognize that the principles of the present invention can be used to advantage with any address type not conventionally used by the signaling network.
In the embodiments described herein, the signaling network associated with the PSTN is an out-of-band common channel system; e.g., a system conforming to the Signaling System Number 7 (SS7/C7) standard. The principles disclosed, however, may be adapted to other networks that rely on addressing protocols that include a destination address field and associated address type field.
In some embodiments, the datagram can also include an origination address of a node of the packet-switched network from which the datagram originated. In a related embodiment, a right of access to the signaling network associated with the PSTN is determined as a function of the origination address. Restricting access to the signaling network may be necessary to prevent malicious activity by unauthorized users.
Systems for routing messages through a signaling network associated with a PSTN, according to the principles disclosed herein, include a first network node for receiving a datagram, wherein the datagram includes a destination address of a destination node of the signaling network having an address format associated with the packet-switched network. The first network node may be on the packet-switched network or the signaling network. In a SS7 signaling network, the first network node can be a Signal Transfer Point (STP). The first network node constructs a message including an address field containing the destination address and a translation type field containing an indicator that the destination address has the address format associated with the packet-switched network. The first network node then transmits the message to a signaling network node. Th
Davidson Walter Lee
Valentine Eric Lee
Ericsson Inc.
EricssonInc
Olms Douglas
Vanderpuye Ken
LandOfFree
Systems and methods for routing a message through a... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Systems and methods for routing a message through a..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Systems and methods for routing a message through a... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2580065