HK1096520A - Systems and methods for home carrier determination using a centralized server - Google Patents

Description

System and method for home carrier determination using a centralized server

Claim priority under 35 clause 119 in the United states

The priority of a provisional application No. 60/503,194 entitled "Using the DNS for home carrier Determination on the MSID Prefix" ("determining home telecommunication office Using DSN Based on MSID Prefix") filed on 9, 15/2003 is assigned to the assignee of the present application and is incorporated herein by reference in its entirety.

Technical Field

The present invention relates generally to wireless communication systems, and more particularly to a method of determining a home network (home network) carrier of a roaming mobile station attempting to access a local network.

Background

With the proliferation of wireless devices, mobile users often find themselves requesting services from service providers other than their home network provider (i.e., home network carrier office). The industry has accommodated this situation by proposing appropriate roaming agreements to provide services to mobile users when they are outside their home network. The home network then maintains information (e.g., in a look-up table) that can be used to identify which home network is associated with the roaming user and which home network is covered by different roaming agreements, respectively.

When mobile users require services in areas outside the limits of their home networks, they contact the local network to request services. The request often includes a username and password provided by the home network. The username and password may be, for example, a publicly available username that is common to many, if not all, users within the same home network office. Upon receipt of a request from a mobile subscriber, the local network uses its locally stored information to determine which home network is associated with the subscriber and from that association determines whether the subscriber should be granted the requested service. This may include checking the username and password in the user's service request against authentication information stored with the home network information.

This arrangement requires not only the initial cost of establishing a local store of information for all home networks, but also the recurring cost of maintaining information in each local network. For example, when information associated with a telecommunications office a changes (e.g., status of roaming agreements, user name, password, etc.), the information must be updated in each local network if a user associated with network a roams in an area associated with one of the local networks. Delays or errors in updating network information may cause service denial for mobile users that are permitted access to the local network. This results in frustration for mobile users and loss of revenue for both local and home network telecommunication offices.

Clearly, the difficulty of maintaining the same home network information in each local network increases proportionally. If there are more home networks, there is more information that must be maintained at each local network. The difficulty of maintaining information in all local networks is exacerbated if there are more local networks (note that a given network may be considered a local network or a home network, depending on the association of the respective network with a particular mobile subscriber).

There is therefore a need in the art for a system and method for authorizing a roaming mobile subscriber to access a local network that overcomes the shortcomings of conventional systems and methods.

Disclosure of Invention

Embodiments disclosed herein address the above stated needs by providing systems and methods for determining a home network carrier associated with a mobile station and authorizing the provision of services to the mobile station. Typically, this is achieved by centralizing the home network information that was stored in each local network in the past (in a conventional manner). The local network then accesses the centrally stored information rather than accessing locally stored and maintained information in order to authorize the roaming user to access the local service.

One embodiment includes a method implemented in a local server, such as a RADIUS server or VLR. The method comprises the following steps: receiving a request for roaming access of a mobile station to a local network; accessing a remote centralized server to identify a home network associated with the mobile station; the mobile station is granted or denied access to the local network based at least in part on which home network is associated with the mobile station.

Another embodiment includes a method implemented in a centralized server, such as a DNS server, wherein the method includes: maintaining a central database containing information associating home networks with mobile stations; connecting the central database to several local servers; receiving a query from a local server identifying a first mobile station desiring to access a local network associated with the local server; and identifying a home network associated with the first mobile station.

Another embodiment includes a local server associated with a local network. The local server is configured to receive a request from a mobile station for roaming access to a local network, access a remote centralized server to determine which home network is associated with the mobile station; access to the local network is granted or denied to the mobile station based on the identity of the home network associated with the mobile station.

Yet another embodiment includes a central server configured to: maintaining a central database having information mapping home networks to mobile stations; receiving a query from a local server, wherein the query includes information identifying a mobile station requesting access to a local network associated with the respective local server; a home network associated with the mobile station identified in the query is identified.

Numerous additional alternative embodiments are also possible.

Drawings

Various aspects and features of the disclosure are described below in the detailed description and with reference to the figures.

Fig. 1 is a schematic diagram of a prior art wireless local network;

FIG. 2 is a schematic diagram of a local wireless network in communication with a remote centralized server of one embodiment of the present invention;

FIG. 3 is a schematic diagram of a local wireless network communicating with a remote centralized server of an alternative embodiment of the present invention;

4A-4D are schematic diagrams of an array of data bits captured from a mobile station ID used to construct a query to a remote centralized server of one embodiment of the present invention;

fig. 5 is a schematic diagram of a plurality of local telecommunication offices in communication with a remote centralized server of one embodiment of the present invention.

While the invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the drawings and detailed description are not intended to limit the invention to the particular embodiment which is described.

Detailed Description

One or more embodiments of the present invention are described below. It should be noted that these and any other embodiments described below are exemplary and are intended to be illustrative of the invention rather than limiting.

As described herein, various embodiments of the present invention include systems and methods for determining a home network associated with a mobile station and authorizing provision of services to the mobile station. Typically, this is achieved by centralizing the home network information that was stored in the past (in a conventional manner) in each local network. The local network then accesses the centrally stored information rather than accessing locally stored and maintained information in order to authorize the roaming user to access the local service.

In one embodiment, a roaming mobile subscriber attempts to access a local service (e.g., internet access) by communicating with a packet data serving node via a radio access network (e.g., a CDMA wireless communication system). The packet data serving node passes the request to the authentication server to obtain authorization to provide the requested service to the roaming user. The service request of the mobile subscriber includes information identifying the mobile device of the subscriber. The identification information is passed to an authentication server which queries a remote centralized server to determine a home network associated with the mobile subscriber. The remote centralized server returns a reply identifying the user's home network (e.g., home network carrier domain name). The home network information is then used by the authentication server to determine whether the mobile subscriber should be granted access to the requested service.

Referring to fig. 1, a schematic diagram of a roaming wireless mobile station communicating with an existing home network system is shown. In this conventional system, a user of mobile station 110 may wish to access a local network to obtain services (e.g., internet access) while roaming. Mobile station 110 communicates with a Packet Data Serving Node (PDSN)130 via a Radio Access Network (RAN)115 that establishes a communication link. Once the communication link has been established, the username/password 120 is communicated to PDSN130 using Password Authentication Protocol (PAP). Thereby allowing the user to be authenticated by PDSN130 prior to providing services to mobile station 110.

PDSN130 generates a remote authentication dial-in user service (RADIUS) request 140 and forwards the request to a local RADIUS server 150 that authenticates the username/password. The local RADIUS server 150 includes a database 155. The database 155 stores information of those home networks to which roaming users attempt to access services via the local network. This information typically includes a table or other information identifying the home network associated with the roaming mobile station requesting access to the local network.

After local RADIUS server 150 has determined which home network is associated with mobile station 110, it may determine whether mobile station 110 should be made to access the requested service by comparing the username/password provided by mobile station 110 to the username/password associated with the home network. The home network username/password may be stored in RADIUS server 150 or RADIUS server 150 may formulate a query and forward the query to a local RADIUS server (not shown) associated with the home network of mobile station 110.

Based on the username/password comparison, RADIUS server 150 authenticates mobile station 110. RADIUS access accept message 160 is then forwarded to PDSN130 whether the username/password is authenticated by local RADIUS server 150 or by the home RADIUS server. PDSN130 forwards a PAP acknowledgement 170 to mobile station 110 in response to the RADIUS access accept message. Mobile station 110 is then allowed access to the requested service.

During the above-described processing, a failure at the PPP level or a delay in the response from PDSN130, local RADIUS server 150, or the home RADIUS server will result in the denial of service to mobile station 110.

The prior art described above requires that each local RADIUS server 150 maintain a database (or some other data structure) containing information for many other networks, including in particular information for each of the other carriers with which the local network is partnered. As noted above, this arrangement is very expensive in terms of additional overhead, equipment, and maintenance of the data contained in the database.

Before describing various embodiments of the present invention, it may be useful to define terms. These terms include:

BS-base station;

the CDG-CDMA development group;

CDMA-CDMA;

NDS-domain name system;

HLR-Home location register;

IMSI-international mobile subscriber identity;

IRM-international roaming MIN;

MIN-Mobile station identification number;

MS-mobile station;

MSC-mobile switching center;

MSID-mobile station ID;

PAP-password authentication protocol;

PDSN-packet data serving node;

RADIUS-remote authentication Dial-in user service;

RAN-radio access network;

VLR-visitor location register.

It should be noted that a mobile station may comprise any wireless device capable of accessing a radio access network, such as a Personal Digital Assistant (PDA), notebook computer, cellular telephone, two-way communicator, pager, or the like (this list is intended to be illustrative and not exhaustive). Those of ordinary skill in the art will understand and appreciate that any other device may access or be adapted to access the RAN and still fall within the scope and teachings of the several embodiments of the present invention.

Further, the type of system in which the MS operates is not limited and may include CDMA, TDMA, GSM or other types of wireless communication systems.

The services that the mobile station is capable of requesting may include voice or data packet type services such as, but not limited to, voice transmission, voice mail, e-mail, text messaging, instant messaging, internet access, telephony, streaming audio, streaming video, online gaming, internet radio, and so forth.

Referring to fig. 2, a schematic diagram of a roaming wireless mobile station in communication with a home network system in accordance with one embodiment of the present invention is shown. The reader should note that reference numerals 110, 115, 120, 130, 140, 150, 160, and 170 correspond to like numbered items in fig. 1.

In this embodiment, MS110 communicates with PDSN130 via RAN 115, and PDSN130 in turn communicates with a local RADIUS server 150. From this point, the configuration of the system begins to differ from the system of fig. 1. Rather than having a database that stores home network information, local RADIUS server 150 connects to a remote centralized server that stores this information. When the local RADIUS server 150 needs the information, a request is sent to the remote centralized server, which then replies with the information. In fig. 2, the remote centralized server is comprised of a CDGDNS server 250. The local RADIUS server 150 is connected to a CDG DNS server 250 via a local DNS server 220 and a conventional internet DNS hierarchy 240.

In one embodiment, the home network information stored by the remote centralized server includes a mapping from the MSID prefix of the MS (requesting access to local network services) to the MS's home network name. The RADIUS 150 server determines the MS home network for voice traffic using the mobile station id (msid), which may be a mobile station identification number, or the International Mobile Subscriber Identity (IMSI). For example, the first 6 digits of a MIN may be mapped to a carrier name. In the embodiment of figure 2, the MSID to home network mapping table is stored and centrally maintained in the DNS server under the authority of a single organization.

It should be noted that the remote centralized server need not consist of a single server or database, but may be a distributed database or server system, depending on the size and needs of the system. For example, remote centralized data may be mirrored to multiple first or second sites to provide spare capacity, server redundancy, or to increase performance if the first server fails or has reduced performance due to high traffic conditions. It is contemplated that a remote centralized server (e.g., a CDG DNS server) will include fewer servers than the number of local RADIUS servers that access home network information.

It should also be noted that although the centralized maintenance server configured in fig. 2 operates under the authority of the CDG (CDMA development group), this need not be the case in other embodiments. The central server may be maintained by other entities, such entities may include industry standards organizations, business enterprises, non-profit organizations, or even individuals. Accordingly, a CDG (e.g., "CDG DNS server" and "CDG. org") should be broadly construed herein as any such entity that maintains a central server or server system in accordance with the present invention.

Other terms in this specification should also be construed broadly unless otherwise indicated. For example, "PAP" should be construed as teaching the use of any suitable authentication protocol (e.g., PAP, CHAP, etc.), rather than a single specific protocol. Also, a "RADIUS" server should be interpreted to cover various different types of remote or roaming access (e.g., VLR) servers and a "MSID" should be interpreted to cover various types of identification information corresponding to the roaming device.

In one embodiment, roaming MS110 desires internet access and sends a publicly available username and password (provided to the MS by its home network) via PAP to the local serving network for authentication. When a connection is established between the MS110 and the PDSN130, the MSID of the MS110 is transferred to the PSDN 130. PDSN130 sends a RADIUS access request 140 to local RADIUS server 150. RADIUS access request 140 contains the MS's username, password, and MSID.

Local RADIUS server 150 sends DNS query 210 to local DNS server 220. In this embodiment, local DNS server 220 is a generic server used only to manage connections and transmissions to and from internet DNS hierarchy 240. The local DNS server 220 sends a DNS query 230 to an internet DNS hierarchy 240 that provides a link to a CDG DNS server 250. The DNS query 230 is forwarded to the DNS server 250, in this case maintained by the CDG.

If DNS server 250 has a mapping from the MSID prefix to the home network domain name, DNS server 250 returns a DNS reply 260 containing the home network domain name. In some embodiments, a local RADIUS and DNS server may cache the mapping of the MSID to the home network provided via a DNS reply. The caching of this information may allow the system to more quickly determine whether to grant future access requests by eliminating the time required for DNS queries and replies. The caching of home network information may be retained and discarded according to an appropriate caching policy.

Upon receiving the DNS reply, local RADIUS server 150 may determine whether MS110 is authorized for access in several ways. For example, in one embodiment, local RADIUS server 150 compares the home network identified in the DNS reply to a set of locally stored roaming agreements. Each roaming agreement identifies a corresponding home network with which the local service network has an agreement to provide roaming services. If the home network identified in the DNS reply is included in the home network having a roaming agreement with the local service network, the local RADIUS server will authorize the MS to access the requested service according to the corresponding roaming agreement. Roaming agreements may authorize access for all users associated with the respective home networks, or they may require the correct username/password to be provided by the user. If correct, local RADIUS server 150 sends a RADIUS access accept 160 to PDSN130, and then a PAP acknowledgement is sent by PDSN130 to MS 110.

In another embodiment, the local RADIUS server contacts only the RADIUS server for the home network, rather than comparing the home network identified in the DNS reply to the home network for which the roaming agreement exists. If the RADIUS server of the home network approves the access authorization requested by the MS, a corresponding reply will be provided to the local RADIUS server. The local RADIUS server will then authorize the MS for the requested access.

It should be noted that these two methods of determining whether to grant access to the MS based on the identity of the home network associated with the MS may also be combined in other embodiments. In yet another possible embodiment, the local RADIUS server may try one method and then another after receiving a DNS reply from the CDG DNS server. For example, the local RADIUS server may first determine whether a home network is included in a network that has a roaming agreement with the local network. If a roaming agreement exists with the home network, access is granted. If there is no roaming agreement with the home network, the local RADIUS server contacts the RADIUS server of the home network to determine if access should be authorized. If the home RADIUS server approves the authorization, the local RADIUS server sends an authorization reply to the PDSN. If the home RADIUS server does not approve the authorization, the local RADIUS server sends a reply to the PDSN denying access.

In another embodiment, if the MS110 desires voice service, the process of authorizing the MS110 and determining the MS's home carrier is substantially the same as the process described above for internet access (i.e., data packet service). Referring to fig. 3, the reader should note that only the differences between the method for voice services shown in fig. 3 and the internet access shown in fig. 2 will be discussed below.

MS110 makes an access request to Mobile Switching Center (MSC)320, and mobile switching center 320 formulates and sends a Visitor Location Register (VLR) query 330 to VLR 340. VLR340 receives MSID 310 of the MS and formulates a DNS query that is sent to CDG DNS server 250, which server 250 replies to the query with the domain name of the telecommunication office (i.e., the MS's home telecommunication office). VLR340 then formulates and sends a Home Location Register (HLR) query 350 to HLR 360. HLR 360 is associated with the home telecommunication office of MS110 identified by CDG DNS server 250. HLR 360 sends HLR reply 370 to VLR340, and VLR340 sends VLR reply 380 to MS 110. In this embodiment, DNS server 250 and VLR 320 may also cache DNS server replies.

In all other respects, the embodiments of the invention shown in fig. 2 and 3 are substantially identical.

As described above, the RADIUS server of the serving network formulates a DNS query based on the MSID and receives a DNS reply containing MS home network information. The MSID is typically sent by the MS to the PDSN, and is therefore convenient to acquire and use to form a query to determine the home network carrier. The first few bits of the MSID may typically be associated with a carrier and captured by PDSN130 and used to formulate a query to be forwarded to local RADIUS server 150.

If the MSID consists of a MIN, the first 6 digits may be associated with the telecommunications office and defined between 2 and 9. For IRM, the first 4 digits may be associated with a telecommunications office, and the first 4 digits are defined as 0 or 1. For an IMSI, the first 5 digits may be associated with a telecommunications office.

Figures 4A-4D show a schematic diagram of an MSID of mobile station 110 resolved into several numerical arrays of inclusions in DNS queries as described above. The MSID array 410 of FIG. 4A illustrates a generic array, where b_nDisplaying the first number of the captured mobile station 110MSID, b_iThe ith number of the MSID is displayed. Reference numeral 420 represents an array of captured numbers, where the order of the numbers is reversed for inclusion in a DNS query. In this case, for array 410, the DNS query will take b_i...b_nCd g org, while for array 420, the DNS query will take b_n...b_iOrg (where cdg is merely an exemplary domain name where DNS servers reside).

FIG. 4B is a schematic diagram of the MSID capture array 430 for MINs, where the DNS query name is taken as B₆.b₅.b₄.b₃.b₂.b₁In min.cdg.org form, wherein b_iIs the ith bit in the MIN.

FIG. 4C is a schematic diagram of an MSID capture array 450 for IMSI, where the DNS query name is taken as b₅.b₄.b₃.b₂.b₁In form of imsi.cdg.org, wherein b_iIs the ith bit in the IMSI.

FIG. 4D is a schematic diagram of an MSID capture array 470 for IMSI, where the DNS query name is taken as b₄.b₃.b₂.b₁Irm.cdg.org form, wherein b_iIs the ith bit in the IRM.

In an alternative embodiment, the DNSThe name can be formed as b for MIN, IRM and IMSI, respectively₁b₂b₃b₄b₅b₆Min.cdg.org (see label 440 in fig. 4B), B₁b₂b₃b₄Irm.cdg.org (see reference 460 in fig. 4C), and b₁b₂b₃b₄b₅Imsi. cdg.org (see label 480 in fig. 4D).

The DNS query is forwarded via the DNS hierarchy to a DNS server authorized by the cd. The DNS server contains an MSID-to-Home Network (MSID-to-Home Network) mapping in the form of DNS resource records. If the MSID prefix bits are resolved to the home network, the DNS server replies with a DNS reply containing the domain name of the home network. For example, if the IRM prefix bit is 1918, the name in the DNS query is the received 8.1.9.1. irm.cdg.org. The DNS server has a resource record mapping 8.1.9.1.IRM tokddi.com, which is the domain name of the KDDI that owns IRM prefix 1918. Com, the DNS reply thus contains kddi.

Fig. 5 is a schematic diagram of a plurality of local carriers 510, 520, and 530 formulating domain name requests and forwarding to a CDG DNS server 550 via the internet 540. This figure is used to illustrate the merging of home network information in a centralized server. If the home network information needs to be updated, the new data may be stored in the CDG DNS server 550. There is no need to update data in each of the local networks 510, 520, and 530. When any of these local networks need access to home network information to identify the home network associated with a particular MS, the information is retrieved from the CDGDNS server 550 via an appropriate DNS query.

It should be noted that various changes could be made to the embodiments described above without departing from the scope of the following claims. Some of these variations have already been mentioned above. For example, upon receiving an identification of a home network associated with the MS, the local RADIUS server may check a locally stored roaming agreement or contact a RADIUS server associated with the home network to determine whether to authorize local network access by the MS. Another variation involves authorizing access by the MS using a username/password. It may or may not need to use these usernames/passwords, and if they are used, they may consist of unique or non-unique usernames/passwords. Yet another variation relates to the identification of the MS for further identifying the corresponding home network. The description of the above embodiments indicates the potential use of MIN, IRM or IMSI MSID information, but other types of information may alternatively be used to identify an MS. Variations of DNS queries based on these different types of identifying information are also described above. These examples are also intended to illustrate the possible variations and broad scope of various embodiments of the invention. It is therefore noted that variations not explicitly included in the present description will still be apparent to the skilled person and are therefore considered to fall within the scope of the description and the following claims.

Although not discussed in detail above, it should be noted that the above-described functions may be implemented in the above-described server by providing programs that run in the respective processing subsystems of these devices. These program instructions are typically embodied in a storage medium and are readable by a corresponding processing subsystem. Exemplary storage media may include RAM memory, flash memory, ROM memory, EPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage media known in the art. Such storage media, on which are embedded program instructions for implementing the functions described above, comprise alternative embodiments of the present invention.

Those of skill in the art would understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

Those of skill would further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the present disclosure

The scope of the invention.

The various illustrative logical blocks, modules, and circuits described in connection with the embodiments disclosed herein may be implemented or performed with a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microprocessor, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. The software modules may reside in RAM memory, flash memory, ROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In the alternative, the processor and the storage medium may reside as discrete components in a user terminal.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (29)

1. A method, comprising:

receiving a request for roaming access of a mobile station to a local network;

accessing a remote centralized server to determine a home network associated with the mobile station;

granting or denying access to the local network to the mobile station based, at least in part, on the determination of the home network associated with the mobile station.

2. The method of claim 1, wherein the method is implemented in a local Remote Authentication Dial In User Service (RADIUS) server.

3. The method of claim 1, wherein the method is implemented in a Visitor Location Register (VLR).

4. The method of claim 1, wherein the accessing a remote centralized server comprises querying a centralized Domain Name Server (DNS).

5. The method of claim 4, wherein querying the centralized DNS comprises formatting a query for delivery to the centralized DNS, wherein the query comprises identification information associated with the mobile station.

6. The method of claim 5, wherein the identification information comprises a Mobile Station ID (MSID).

7. The method of claim 6, wherein the MSID is selected from the group consisting of: mobile station identification number (MIN); international roaming min (irm); and International Mobile Subscriber Identity (IMSI).

8. The method of claim 1, further comprising determining whether a home network associated with the mobile station is among one or more networks to which a user of the respective mobile station authorizes access to the local network via a roaming agreement.

9. The method of claim 1, further comprising querying a remote RADIUS server associated with a home network associated with the mobile station to determine whether the mobile station is authorized to access the local network.

10. The method of claim 1, further comprising caching information received in response to accessing a remote centralized server.

11. A method, comprising:

maintaining a central database containing information about a home network and the home network's association with a mobile station;

connecting said central database to a plurality of local servers;

receiving a query from one of the plurality of local servers, wherein the query includes identification information associated with a first mobile station requesting access to a local network associated with the local server;

a home network associated with the first mobile station is identified.

12. The method of claim 11, wherein the information about the home network and the home network association with the mobile station comprises: mapping of identification information associated with one or more mobile stations to one or more home networks associated with the one or more mobile stations.

13. The method of claim 12, wherein the mapping of the identification information associated with the mobile station to the home network comprises: mobile station id (msid) to home network.

14. The method of claim 13, wherein the MSID is selected from the group consisting of: mobile station identification number (MIN); international roaming min (irm); and International Mobile Subscriber Identity (IMSI).

15. The method of claim 11, further comprising:

receiving queries from one or more additional local servers, wherein the queries include identification information associated with one or more additional mobile stations requesting access to one or more additional local networks associated with the additional local servers;

one or more additional home networks associated with the additional mobile stations are identified.

16. An apparatus, comprising:

a local server associated with a local network, wherein the local server is configured to:

receiving a request for a mobile station to roam access to the local network,

accessing a remote centralized server to determine a home network associated with the mobile station;

granting or denying access to a local network to the mobile station based, at least in part, on the determination of the home network associated with the mobile station.

17. The apparatus of claim 16, wherein the local server comprises a Remote Authentication Dial In User Service (RADIUS) server.

18. The apparatus of claim 16, wherein the local server comprises a Visitor Location Register (VLR).

19. The apparatus of claim 16, wherein the local server is configured to generate a Domain Name Server (DNS) query and send the query to a centralized DNS.

20. The apparatus of claim 19, wherein the local server is configured to format a DNS query that includes identification information associated with the mobile station.

21. The apparatus of claim 20, wherein the identification information comprises a mobile station id (msid).

22. The apparatus of claim 21, wherein MSID is selected from the group consisting of: mobile station identification number (MIN); international roaming min (irm); and International Mobile Subscriber Identity (IMSI).

23. The apparatus of claim 16, wherein the local server further comprises a local memory configured to store roaming agreement information, wherein the local server is configured to determine whether a home network associated with the mobile station is among one or more networks for which a corresponding mobile station user authorizes access to the local network via a roaming agreement.

24. The apparatus of claim 16, wherein the local server is connected to a remote RADIUS server associated with a home network associated with the mobile station, wherein the local server is configured to query the remote RADIUS server to determine whether the mobile station is authorized to access the local network.

25. The apparatus of claim 16, the local server further comprising a local memory configured to cache information received in response to accessing a remote centralized server.

26. An apparatus, comprising:

a central server configured to:

maintaining a central database containing information about a home network and the home network's association with a mobile station;

receiving queries from a plurality of local servers, wherein each query includes identification information associated with a mobile station requesting access to a respective local network associated with the respective local server;

a home network associated with the mobile station identified in the query is identified.

27. The apparatus of claim 26, wherein the central server is configured to store a mapping of identification information associated with one or more mobile stations to one or more home networks associated with one or more mobile stations.

28. The apparatus of claim 27, wherein the mapping of identification information associated with the mobile station to the home network comprises a mapping of a mobile station id (msid) to the home network.

29. The apparatus of claim 28, wherein the MSID is selected from the group consisting of: mobile station identification number (MIN); international roaming min (irm); and International Mobile Subscriber Identity (IMSI).