Multiplex communications – Pathfinding or routing – Switching a message which includes an address header
Reexamination Certificate
1999-10-26
2004-09-21
Pham, Chi (Department: 2667)
Multiplex communications
Pathfinding or routing
Switching a message which includes an address header
C370S466000
Reexamination Certificate
active
06795444
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The present invention relates to telecommunication systems and, more particularly, to systems and methods for providing wireless telephony over a packet-switched network such as, for example, a network using the Internet Protocol (IP).
2. Description of Related Art
Coupled with the phenomenal growth in popularity of the Internet, there has been a tremendous interest in using packet-switched network (PSN) infrastructures (e.g., those based on IP addressing) as a replacement for the existing circuit-switched network (CSN) infrastructures used in today's telephony. From the network operators' perspective, the inherent traffic aggregation in packet-switched infrastructures allows for a reduction in the cost of transmission and the infrastructure cost per end-user. Ultimately, such cost reductions enable the network operators to pass on the concomitant cost savings to the end-users.
The existing Voice-over-IP (VoIP) networks implement communications infrastructures that are typically based on multiple protocols which include, for example, the well-known H.323 protocol. These protocols are primarily oriented to operating with fixed-network-based telecommunications protocols and are designed to provide such services as call control, et cetera, for wireline subscribers only. Current VoIP systems, accordingly, cannot be used advantageously in wireless environments, although some VoIP systems may support rudimentary location management services.
There also exist several inadequacies in the Plain Old Cellular System (POCS) with respect to supporting IP-based infrastructures and services. Also, there exist deficiencies and shortcomings in the existing IP-based VoIP systems in terms of supporting wireless access technology such as for example, ANSI-136, Global System for Mobile communications (GSM), IS-95, et cetera. Some of the more significant of these inadequacies and shortcomings are summarized below.
First, current POCS systems and technology infrastructures are not compatible with communications infrastructures as required by the VoIP standards. The operation, maintenance, and the connection management required by the traditional POCS systems are based on switched physical trunk connections. These mechanisms are not compatible with the packet switching/routing mechanisms such as, e.g., Domain Name System (DNS), Dynamic Host Configuration Protocol (DHCP), etc. required for managing device/host addressing and configuration.
Incompatibilities also exist between POCS protocols and communications protocols of the existing VoIP applications. The POCS systems cannot support a Plain Old Telephone System (POTS) or Integrated Services Digital Network (ISDN) client in the Internet context. The Internet “client” is typically required to handle Internet-based protocols such as, e.g., Real-time Transfer Protocol (RTP), Resource Reservation Protocol (RSVP), etc. which are not in the definition or domain of the POCS systems.
Another important disparity which should be noted is that the POCS signaling and user data planes use distinct physical transport and network facilities. The IP-based networks are flexible in that they can support any higher layer protocols, and information can be transmitted over any lower layer e.g., a link or physical layer. Moreover, the higher layer protocols may be used for signaling as well as user data.
With respect to the inadequacies of the existing VoIP systems, it should be appreciated that current VoIP clients and infrastructure can handle neither the wireless access-side technology nor the basic network-side functional signaling plane which enables mobility management, authentication/security, service definition, service mitigation and execution, et cetera. Clearly, the provision of such advancements in the POCS as Wireless Intelligent Network (WIN) services, can only magnify these and other disparities and incompatibilities between the POCS and VoIP infrastructures.
Based on the foregoing, it is apparent that in order to address these and other problems of the current technologies set forth above, what is needed is a seamless integration between the existing POCS and VoIP infrastructures so that the numerous advantages, known and hitherto unknown, of packet-based networks may be realized within the context of wireless telecommunications. The present invention provides such a solution.
SUMMARY OF THE INVENTION
In exemplary embodiment, the present invention advantageously integrates the existing VoIP packet switching infrastructures with the POCS by selectively replacing structural and functional elements that allow the existing VoIP and POCS systems to co-exist and evolve independently. In other words, legacy infrastructures in each realm are left intact to the extent possible in order to provide backward compatibility. Accordingly, in the presently preferred exemplary embodiment of the present invention, available VoIP functions are substituted for corresponding ANSI-136/41 functions, while the remaining ANSI-136 functions preferably continue to exist in their legacy form. To minimize infrastructure modifications, a mechanism is introduced for interfacing the “footprint” of a VoIP system with the POCS legacy structures with respect to call control, mobility management, subscriber services, et cetera.
Accordingly, a presently preferred exemplary embodiment is directed to an integrated network system comprising a packet-switched network portion and a cellular telecommunications network portion, with an interworking function module (or proxy device) disposed therebetween for interfacing between the legacy POCS and VoIP PSN infrastructures. The proxy device is preferably comprised of a “VoIP proxy” or “IP client” and a mobility gateway (MGW or Mob.GW). The MGW preferably handles signaling information between the POCS CSN and PSN infrastructures. The proxy/IP client, on the other hand, handles IP traffic (signaling and user data, which includes voice or other information) therebetween for mobility management, security and subscriber services, respectively. Accordingly, the proxy makes, or provides, the link between, on the one hand, the POCS legacy mobility, security, subscriber services and supplementary WIN services, and on the other hand, the VoIP PSN-specific legacy mobility management, security and services, regardless of whether these are interfaced from the IP client, or the server disposed in the VoIP infrastructure.
The MGW's role is preferably to “gate” the transfer of control signaling information relating to the aforementioned functions. In accordance with the teachings herein, the functionality of a presently preferred exemplary embodiment of the Mob. GW (or MGW) is summarized below.
A Mob. GW implements the mobility management entity that maintains the MS-associated VoIP infrastructures' location information. The Mob. GW handles the ANSI-41 automatic roaming signaling interface for location management towards the ANSI-41 (a subset of the D interface). In this sense, it is seen as a Visitor Location Register (VLR) by the ANSI-41 PLMN. It also implements the PSN-specific location management signaling interface to and from the PSN infrastructure (e.g., RAS, SIP signaling etc.). Hence, the Mob. GW is also a protocol converter between the ANSI-41 and H.323/SIP signaling.
The Mob. GW also handles the call routing interface between the ANSI-41 PLMN and PSN VoIP networks. This mechanism enables (i) the routing of a call and/or service from the PSN towards the associated ANSI-41 PLMN portion; and (ii) the routing of a call and/or service from the ANSI-41 PLMN portion towards the served PSN VoIP system. Thus, the Mob. GW handles the part of the ANSI-41 automatic roaming signaling interface for call delivery (e.g., location requests, route requests, etc.) towards the ANSI-41 PLMN. On the PSN side, the Mob. GW implements the H.323 or SIP call routing interface.
In one exemplary embodiment, the proxy device or its constituents (i.e., Mobility GW, various IP clients, etc.) may be imple
Balazinski Bartosz
Bertrand Jean-Francois
Foti George
Lu Yang
Lupien Francis
Boakye Alexander O.
Pham Chi
Smith & Danamraj, P.C.
Telefonaktiebolaget L M Ericsson (Publ)
LandOfFree
System and method for providing wireless telephony over 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 System and method for providing wireless telephony over a..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and System and method for providing wireless telephony over a... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3215653