Patent Application
20060146794
This invention relates generally to interaction between two or more discrete and separate communication system peers.
Communication systems of various kinds are known. At present, numerous discrete communication systems operate as separate peers with respect to one another. For example, both cellular telephony wireless communication systems and iDEN® wireless communication systems operate independently of one another and provide wireless communication services to their respective subscribers. Notwithstanding the separate and distinct nature of these deployed systems, however, in many cases it is desirable or even essential that at least some interaction between such peer systems be supported. For example, it may be desirable to support a communication between subscribers of two such peer systems.
Various approaches exist to support and facilitate such interaction. In general, relatively high-density connectivity tends to characterize present successful efforts (where, for example, each node essentially links directly to every other available node). Unfortunately, this approach holds poor prospects for any going-forward scenario that anticipates system growth. In general, this approach scales badly; in particular, as systems grow in size and/or complexity, an even greater increase is experienced with respect to required corresponding connectivity. This, in turn, quickly renders this approach both cost ineffective and ultimately undeployable.
Attempts to support such interconnectivity using reduced connectivity topologies has introduced other difficult problems relating, in particular, to call processing inefficiency. Long call setup delays become more common, and excessive queries to subscriber databases (such as, for example, Home Location Registers (HLRs)) become more common. Excessive rerouting (and/or redirecting) of calls also occurs.
As a result, interconnectivity as between peer networks in many cases remains problematic and tending towards unsatisfactory performance and/or cost.
The above needs are at least partially met through provision of the peer network interaction facilitation method described in the following detailed description, particularly when studied in conjunction with the drawings, wherein:
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions and/or relative positioning of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention. It will also be understood that the terms and expressions used herein have the ordinary meaning as is accorded to such terms and expressions with respect to their corresponding respective areas of inquiry and study except where specific meanings have otherwise been set forth herein.
Generally speaking, pursuant to these various embodiments, interaction between at least a first and a second communication network are facilitated (where these networks comprise discrete and separate communication system peers). In a preferred approach, at least one of these networks is functionally partitioned at least with respect to interrogation and call signaling procedures over a plurality of geographic service areas.
To effect this facilitation, and pursuant to a preferred approach, one provides a gateway for at least the first communication network. This gateway provides functionally partitioned interrogation and call signaling procedures for a first one of the plurality of geographic service areas but not for at least one other of the plurality of geographic service areas. Upon then receiving a call routing message (comprising any of a wide variety of call signaling messages such as, but not limited to, a Session Initiation Protocol INVITE message) from a source in the second communication network, which message identifies a target communication unit that is currently serviced by the first communication network, one then processes the call routing message as a function, at least in part, of a home geographic service area and a serving geographic service area as corresponds to the target communication unit.
In accordance with the needs and/or capabilities of a given application, this processing can comprise determining whether the call routing message identifies a specific call signaling server in the first communication network. When true, a decision to use, or to not use, the identified specific call signaling server can be based, at least in part, upon an ascertained status of one or more network elements and/or items of information. It is also possible, depending again upon the needs or capabilities of a given application, to condition or influence such processing with respect to the availability or lack of availability of pertinent cached information. Serving capability can also be taken into account if desired.
These and other benefits may become clearer upon making a thorough review and study of the following detailed description. Referring now to the drawings, and in particular to
Pursuant to a preferred approach, a plurality of gateways are also deployed to effect interaction between the first and second communication networks 10 and 11. Two such gateways 12 and 13 are shown, but it will be understood that there is no particular upper limit regarding how many gateways may serve in a given application. In a preferred approach, at least some (and preferably all) of these gateways provide functionally partitioned interrogation (i.e., queries to a subscriber database such as a Home Location Register to determine a target's registered service location) and call signaling procedures (i.e., signaling and interworking procedures required or useful to establish and/or maintain a call between an originating and a target call server from respective peer networks) for one or more (but not all) corresponding geographic service areas of the first communication network 10.
For example, and as a non-exhaustive illustration of this point, the first gateway 12 in this embodiment provides functionally partitioned interrogation and call signaling procedures for a first through an Nth geographic service area 14 and 15, but not for an Oth geographic service area 16. In turn, a second gateway 13 provides such support for the Oth geographic service area 16 but not for the earlier-mentioned geographic service areas 14 and 15. In a preferred approach, while one gateway may serve a plurality of geographic service areas (though not all available geographic service areas), each geographic service area is served by only a single gateway.
Such an architecture means, for example, that the first gateway 12 cannot interrogate the Home Location Register as corresponds to the Oth geographic service area 16 though it can interrogate the Home Location Register of, for example, the first geographic area 14. Those skilled in the art will recognize that this contrasts sharply with the more fully-meshed configurations that typify a prior art deployment. This more lightly-meshed configuration in turn facilitates less complicated increased scaling. In particular, the number of geographic service areas supported, and the number of gateways used to effect that support, can be greatly increased without also exponentially increasing the corresponding fabric that couples the former to the latter.
It will also be appreciated that, in effect, any given gateway may support in a given instance both, one, or neither of the interrogation and call signaling functions depending, typically, on:
the target's home geographic service area;
the target's current registered geographic service area; and/or
the availability of useful cached routing information as gleaned from a previous call (or calls).
In an optional but preferred approach, and referring now to
Referring now to
As a general proposition, this approach permits and facilitates the earlier described deployment of less-than-fully-meshed gateways. This, in turn, permits a degree of scalability that is quite lacking in prior solutions. Further details regarding these receiving and processing steps are provided below.
As already described above, such a gateway will receive, from time to time, call routing messages from a source in a remote communication network that identifies a target within the communication network served by the gateway. As an optional but preferred approach, and referring now to
Regardless of whether the gateway effects such caching functionality, and referring now to
When not true, however, the gateway can respond by automatically redirecting 52 the source to another gateway for the first communication unit. Although the gateway could forward the message on to the identified gateway, by redirecting the source to the new gateway the source (via, for example, its own gateway) has the opportunity to cache the new routing information and to use it going forward to essentially avoid a sequence of multiple communication hops that tend to characterize message forwarding techniques.
As an optional but preferred step, the gateway can also indicate 53 to the source that this redirection comprises a temporary redirection (using, for example, a Session Initiation Protocol-compatible 302 message as is understood in the art). This indication can be used by a recipient network element, such as a receiving gateway, to discourage the recipient element from caching the corresponding routing information, as this temporary redirection may well be non-applicable in a future instance. So configured, the gateway serves to ascertain whether the target is presently within a geographic service area of the first communication network that is serviced by the gateway (recalling again that, pursuant to a preferred deployment, this gateway is not meshed to each and every geographic service area that comprises the first communication network). When not true, (meaning that the target is not presently within a geographic service area effectively coupled to the gateway), the gateway can respond by redirecting the source to another gateway for the first communication network and can also, if desired, indicate that this redirection is temporary to accommodate a situation where, for example, a target that is ordinarily serviced via a particular Home Location Register for a particular geographic service area that is coupled to the gateway has temporarily roamed to a geographic service area that is not coupled to the gateway.
The aforementioned redirection can occur in any of a variety of ways. As one example, and presuming the absence of any useful information upon which to base a decision, the gateway can simply redirect the call to a home gateway based on available network configuration data. Or, as an alternative and presuming the availability of pertinent information (as may be available via, for example, a Home Location Register that is accessible to the gateway and/or via previously cached information), the gateway may be able to redirect the source to another gateway that, in fact, likely provides present support to the target. When certain of the accuracy of such redirection information, if desired, the gateway can also include an indication in the redirection message to specify the vouched-for status of the redirection information.
Referring now to
When the call routing message does not identify a specific call signaling server as comprises a part of the first communication network, and such information is not otherwise available in the gateway's cache memory, the gateway can then determine 63 whether the location server for the target communication unit is within a geographic service area as corresponds to the interrogation facilitation services coverage of the gateway.
When false, the gateway can respond by automatically redirecting 64 the source to another gateway for the first communication network that is known to facilitate interrogation services for the target communication unit. In this event, it may also be desirable to provide an automatic indication to the source that this redirection comprises a non-temporary redirection (via, for example, a Session Initiation Protocol-compatible 301 message as is known in the art). Such an indication can be used by a recipient device, such as a recipient gateway, to prompt caching of the routing information to thereby aid in avoiding redirection in support of subsequent communications. Again, selection of the particular gateway to which the source is redirected can be effected in any of a variety of ways with a particular selection technique or criteria depending upon the needs and/or resources and capabilities that characterize a given application.
When the gateway determines 63 that the location server for the target communication unit is within a geographic service area as corresponds to the call signaling facilitation services coverage of the gateway, the gateway can then interrogate 65 a corresponding location server and then proceed to determine 51 whether the target is within a call signaling facilitation service area (as described above with respect to
When the gateway determines 60 that the message does in fact identify a specific first network call signaling server, the gateway can then determine 66 whether that call routing message also comprises or otherwise indicates or identifies a particular status of relevance to these processes. In particular, the identification of a specific call signaling server may be accompanied by a specific indicator that effectively vouches for the accuracy of the specific call signaling server as being a correct one. This has particular relevance when the received call routing message itself comprises a response to an earlier received redirection message from another gateway that serves the first communication network. For example, that earlier gateway, in addition to ascertaining its own inability to service the call via its own geographic service areas, may have been able to also ascertain with certainty a present location of the target. In such a case, the prior gateway may have not only provided a redirection instruction but may also have included an indication that essentially vets the provided information as being current and accurate. The receiving element, upon then forming its renewed call routing message, may then include this (or a corresponding) indication regarding this vouched-for status of the accompanying information.
When this indicated status matches or otherwise corresponds in some required fashion to a predetermined status X (for example, a vouched-for status as described above), the gateway can then preferably use 67 the provided identification of the specific call signaling server as appears in the call routing message when processing the call routing message.
When not true, however, meaning that the identified status does not accord in a required fashion with a predetermined standard or value, the gateway can instead preferably ascertain 68 whether cached information regarding identification of an appropriate call signaling server is otherwise available to the gateway. When true, the gateway can then use 69 that cached information in lieu of the specifically identified call signaling server to process the call routing message. When not true (which may reflect either an absence of relevant cached information or only the availability of likely stale or outdated cached information), the gateway can instead still opt to use 67 the information identifying the specific call signaling server.
So configured, the gateway is able to respond usefully and dynamically to a variety of call routing circumstances. For example, the gateway can effectively handle both call routing messages that specify a particular call signaling server and those that do not, in part through provision of an ability to automatically determine its own interrogation capabilities. The gateway is also provided with an ability to make dynamic use of its own serving capabilities and, just as importantly, its knowledge regarding its lack of serving capabilities in some instances. These avenues of response, in turn, aid in mitigating long call setup delays, excessive queries to subscriber databases, and the excessive rerouting (or redirecting) of calls.
In effect, certain available techniques (such as Session Initiation Protocol-based routing, caching, and addressing) are leveraged (through use and/or extension) in new ways to effect these desired results. By functionally partitioning independent support of interrogation procedures from call signaling procedures as described, a gateway can ascertain its ability to support both, one, or neither of these activities with respect to any given incoming call from a peer network. In particular, the gateway is able to leverage this configuration through use of a given target's home geographic service area, the target's current registered geographic service area (which may comprise an area to which the target has roamed), and/or the availability of useful or potentially useful cached routing information from a previous call or calls.
Those skilled in the art will especially appreciate the (sometimes dramatic) reduction in redirection messages and interrogation messages that can be achieved via deployment of these teachings. To illustrate, and referring now to
The source can then simply select 72 a first one of the listed gateways using any desired selection mechanism (including but not limited to a simple random selection) and transmit an INVITE message 73 to that first gateway. This INVITE message 73, of course, will identify the target. In this example, and due to the unmeshed nature of the preferred system configuration, the first gateway does not comprise a gateway having access to the Home Location Register for the target.
This first gateway, however, will have access to information that correlates the target to a given one of the system's gateways that does have such access. The first gateway can therefore identify the home gateway 74 for this target and issue a 301 REDIRECT message 75 to the source that identifies the home gateway for the target (which home gateway has access to the Home Location Register for the target). This 301 REDIRECT message 75 comprises, pursuant to these teachings, a message indicating that the purpose of the redirection is to facilitate a subsequent interrogation of the home gateway.
The source responds by directing an INVITE message 76 to the home gateway as was identified in the 301 REDIRECT message 75. This home gateway has access to the Home Location Register for the target. In this illustrative example, however, the target is not registered in its home region. Instead, in this example, the target has roamed to another region and hence the home gateway does not presently comprise the serving gateway for the target. In accord with present practice the Home Location Register is aware of this situation and further has the identifying information for the serving gateway. The home gateway is therefore able to identify 77 the serving gateway and to provide a 302 REDIRECT message 78 to the source to identify this serving gateway.
As described above, this 302 REDIRECT message 78 can additionally convey the information that the source (and hence the serving gateway) does not need to interrogate the serving gateway with respect to the location of the target, as the Home Location Register has already provided this information and effectively vouched for the present location information of the target. Pursuant to these teachings, then, the source is able to issue an INVITE message 79 to the serving gateway to not only identify the target but to also indicate that there is no need for the serving gateway to further interrogate the Home Location Register, nor its local cache memory, with respect to the present location of the target. Instead, the serving gateway can then simply effect its ordinary processes to complete establishing the desired communication link with the target as is registered in the service area of the serving gateway.
It will therefore be seen that, even under what essentially amounts to a worst case scenario, only two redirections are required to successfully connect an external source to a correct serving gateway when employing the above-described teachings. It will further be appreciated that, in the above illustrative example, neither the first gateway nor the home gateway had previously cached contact information that could have been employed to avoid at least one of these two redirection exercises. In many cases, these teachings will permit the collection and use of such cached information to effect such a reduction in redirection steps. Those skilled in the art will also further appreciate that, in the above illustrative example, only one interrogation of the Home Location Register was required to facilitate completion of the communication link notwithstanding that two redirections were employed to ultimately direct the source to the serving gateway.
Those skilled in the art will recognize that a wide variety of modifications, alterations, and combinations can be made with respect to the above described embodiments without departing from the spirit and scope of the invention, and that such modifications, alterations, and combinations are to be viewed as being within the ambit of the inventive concept. For example, as described above, the gateway can optionally cache potentially useful information regarding a source from a communication system peer upon receiving a call routing message that identifies a target within the communication system served by the gateway. Similar caching behavior can also be applied when supporting interactions in a reverse direction, however. To illustrate, and referring now to
