Abstract:
A system for routing short messages between message centers provides that messages are first checked to see if they are to be handled by the local message center, and then routed, if appropriate, to another message center using point code or global title translation routing.

Description:
COPYRIGHT NOTICE/PERMISSION 
     A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever. The following notice applies to the software and its interfaces as described below and in the drawing hereto: Copyright© 1998, ADC NewNet, Inc. All Rights Reserved. 
     TECHNICAL FIELD OF THE INVENTION 
     The present invention relates generally to mobile telephone systems, and more particularly to method and apparatus for routing short messages between multiple message centers. 
     BACKGROUND OF THE INVENTION 
     The Short Message Service for IS-41 (ANSI-41) mobile networks is defined in the ANSI/EIA/TIA standard starting with version C (also known as IS-41-C) (See ANSI/EIA/TIA Standard 41-D,  Cellular Radio - Telecommunications Intersystem Operations , Electronics Industries Association, 1997) (“IS-41D Specification”). This document defines network entities called Mobile Centers (MCs) which are responsible for receiving, storing and forwarding short messages from and to Short Message Entities (SMEs). In most cases, these entities correspond to mobile handsets (MSs), and are formally defined as MS-based SMEs. In some cases, these SMEs can be based on the mobile center or other network nodes, and are known as fixed SMEs. 
     The underlying transport layer for IS-41 messages is usually SS7. The IS-41 entities in the SS7 network are addressed using Point Code/Subsystem Number (PC/SSN) identifiers. On the other hand, short messages are addressed using MINs (Mobile Identification Numbers) or DNs (Destination Numbers). corresponding to the telephone numbers of the mobile handset. 
     In general, the short message is delivered to an MC, which stores the message. The MC will attempt to deliver a message during a certain period. Since the destination may be temporarily unreachable (e.g., the subscriber&#39;s handset is out of range), the MC may attempt to deliver several times. The standard also allows one MC to forward the message to another MC, which will actually make the delivery. 
     The signaling procedures for standard MC interworking are specified in Section 6 of the IS-41D Specification. Section A4.46.6 MC Receiving and SMSDeliveryPointToPoint INVOKE@ describes in pseudo-code how a short message is treated by an MC. There are three actions that while mentioned are not specified: 
     1) How to determine if the original originating address is a SME homed to the local MC  10  (step  1 - 16 - 1 ). 
     2) How to determine if the destination address is a SME homed to this MC  10  (step  1 - 17 - 1 ). 
     3) How to determine where to forward the message (step  1 - 16 - 1 - 3 , referring to procedure 4.46.7). 
     Thus, the standard ([IS41D]) does not specify how to determine the home MC or how to route (that is, how to determine the PC/SSN address) a short message from one MC to another. In their book entitled  Mobile Telecommunication Networking with IS -41, (McGraw-Hill, 1997), Michael D. Gallagher and Randall A. Snyder discuss the routing for forwarding the short message between two MCs. Their suggestions are fixed MIN-to-MC table (similar to the internal MC route table described below) or MIN-to-MC Global Title Translation (GTT). While Gallagher and Snyder describe how to do routing, they offer no solution for making the home MC determination. 
     SUMMARY OF THE INVENTION 
     One embodiment of the invention offers a flexible approach for determining whether a given subscriber is homed to the local MC. The combination of subscriber database profiles and default subscriber profiles allows the customer to implement schemes such as white-listing (only explicitly provisioned subscribers receive service), black-listing (all receive service except those explicitly disallowed in the database), or some combination. 
     In addition, one embodiment of the invention offers a flexible routing mechanism which allows a combination of point code and global title translation routing. Furthermore, the invention allows the customer to try to deliver a message directly if the forwarding fails (for instance of the destination&#39;s home MC is unknown or consistently unreachable). 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     FIG. 1 illustrates a plurality of message centers interconnected with an SS7 signaling network. 
     FIG. 2 illustrates a message center processing system in simplified form. 
     FIGS. 3A and 3B illustrate the software and corresponding process for processing short messages according to one example embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings that form a part hereof, and in which are shown by way of illustration specific embodiments in which the invention may be practiced. It is understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention. 
     Referring now to FIG. 1, there is illustrated a plurality of message centers  10   a - 10   d , interconnected with an SS7 network  12 , which includes SS7 links  11 . As described herein, message centers  10  transfer short messages between one another over the SS7 network. In this example embodiment of the invention, short messages are transported and delivered in accordance with the Short Message Service for IS-41 (ANSI-41) mobile networks as specified above. Although described herein in the form of an SS7 network, other transport architectures may also be used for the purpose of transporting short messages. 
     Referring now to FIG. 2, there is illustrated in simplified form a short message processing system  13 , according to one example embodiment of the invention. As illustrated, short messages are received at processing system  13  from an SS7 link  11 , or from another source over port  15 , that may originate from within or without the message center  10 . System  13  includes a hardware platform  14   b  and software components  14   b . System  13  further includes a subscriber database  14   c , maintaining a list of subscribers served by the message center  10 , and also a routing table  14   d , pursuant to conventional IS-41 operation. Hardware platform  14   a  is preferably a workstation computer configured to provide a physical layer connection to the SS7 links  11  and to other external devices and networks. Software components  14   b  preferably include a UNIX type or equivalent multitasking operation system, and other software for implementing control functions for message processing, for example as illustrated with respect to the flow chart of FIGS. 3A and 3B. 
     Referring now to FIGS. 3A and 3B, there is described one embodiment of the message processing method and software of the invention. A short message is received at the processing system  13  ( 20   a ). A check is made to see if the message is qualified ( 20   b ), and if not, it is rejected or otherwise processed ( 20   e ). Qualifying the message is not essential to the invention, but may be done by determining if the originating address (phone number of originating program or handset) matches a specific profile in the local subscriber database  1   c , with the profile determining whether the message is accepted for processing or rejected. If the subscriber database  14   c  does not have a match, a default subscriber profile can be used to determine whether the message is accepted for processing or rejected. 
     If the message is accepted for processing, it is determined whether the destination address is homed to the local MC  10 . More particularly, if the destination address (phone number of destination program or handset) matches a specific profile in the local subscriber database  14   c  ( 20   c ), the profile determines whether the message will be delivered directly (following standard [IS41D] procedure) or rejected ( 20   d ). 
     Otherwise, the message is forwarded to the home MC  10  of the destination. If the point code (PC)/sub-system number (SSN) of the destination&#39;s home MC  10  is in the MC route table ( 14   d ) ( 20   f ), then the short message is forwarded to the destination MC  10  using the PC/SSN ( 20   g ). 
     Otherwise, global title translation (GTT) is attempted for MC  10  routing ( 20   i ), and if successful the message will be forwarded to the destination&#39;s home MC  10  using the destination address and MIN-to-MC translation. 
     Alternatively, the invention may be embodied such that only one of the above routing procedures is configured, (i.e. either routing by point code or by GTT), or routing is done by first trying one routing technique, and then the other if the first is not achievable. 
     If any event the forwarding step fails ( 20   h ) (for instance of the destination&#39;s home MC is unknown or consistently unreachable), the default subscriber profile determines whether the message will be delivered directly or rejected ( 20   j ). 
     Alternate Embodiments 
     The present invention is in no way limited to the example embodiment described herein. The invention is not limited to any type or form of software. Nor is it limited to any particular type of hardware or operating system platforms, or client-server or network architecture. Moreover, the messaging system of the invention may also be implemented in alternate ways without departing from the scope of the invention. Furthermore, the software of the invention may also be implemented in whole or in part in hardware, and vice versa. 
     Conclusion 
     Thus, the present invention offers a flexible approach for determining whether a given subscriber is homed to the local MC. The combination of subscriber database profiles and default subscriber profiles allows the customer to implement schemes such as white-listing (only explicitly provisioned subscribers receive service), black-listing (all receive service except those explicitly disallowed in the database), or some combination. In addition, the invention offers a flexible routing font mechanism which allows point code routing, GTT routing, and a combination of the two. Furthermore, the invention allows the customer to try to deliver a message directly if the forwarding fails.