FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENT RULES, 2003
COMPLETE SPECIFICATION
(See Section 10 and Rule 13)
Title of invention:
SYSTEM AND METHOD FOR CALL ROUTING IN A COMMUNICATION SYSTEM BASED ON USER SELECTED PREFERENCE MODES
Applicant
Tata Consultancy Services Limited A Company Incorporated in India under The Companies Act. 1956
Having address:
Nirmal Building, 9th Floor,
Nariman Point, Mumbai 400021.
Maharashtra, India
The following specification particularly describes the invention and the manner in which it is to be performed.

FIELD OF THE INVENTION
[001] The present invention relates to a field of communication systems. More particularly, the present invention relates to the systems and methods for routing a call within the communication system based on a user selected preference mode.
BACKGROUND OF THE INVENTION
[002] The current telecommunication systems take into consideration various parameters like quality, service, delay, bandwidth and cost. Cost plays a major role in today's telecommunication networks as most of the service providers try to provide cost effective user products and services. The service providers, in quest of earning maximum revenue provide a variety of charging plans which may benefit end users. However, in many of the scenarios, the charging plans are applicable to a particular type connecting entity. Thus, after subscribing to any charging plan, the user has to be vigilant while initiating any communication session so as to attain the maximum benefit out of the plan so subscribed.
[003] Along with the present facilities provided by many telecommunicating systems, it is not always possible for the end user to utilize the charging plans for their maximum benefit due to absence of any method or system to track the initiation of session based on the revenue benefits of charging plan. Several users of cellular phones have more than one telephone device-where each device is assigned a different telephone number or same device holds more than one telephone number. The end user may also have personal telephones such as mobile phones, landline or work telephone. In order to contact the terminating user (called party), the subscriber (calling party) has to dial any one of the telephone numbers. At times, the subscriber may have to dial all the numbers in order to reach the terminating user. Generally, the subscriber places a telephone

call to the telephone number assigned to the terminating user at which the terminating user is most likely to respond. If the terminating user does not respond to the initial call, the subscriber dials subsequent numbers available in his/her contact list of the terminating user. Also, it is difficult for the subscriber to remember the priority of number for a particular connecting party or terminating user.
[004] Although there were more than one contact for any particular terminating user, the call will only be routed to the number which was mentioned in the 'TO' header (if in case SIP protocol is used as a communication medium) i.e., the dialed number. Based on one's charging plan, the existing system fails to inform the user about that number that should be dialed in order to ensure the cheapest network path for the subscriber. There is no system and method in place to revisit the charging profile of the user placing call, to select the best possible cheapest number at that particular time and then route the call accordingly.
[005] Also, in the existing IP Multimedia Systems using SIP as a protocol, there is no provision for the originating user to send more than one destination number to the ISP and select any one of the number based on his/her priority or select a cheapest number to make a call.
SUMMARY OF THE INVENTION
[006] This summary is provided to introduce concepts related to system and method for routing a call through a network, system and method for session initiation in a communication device of a subscriber and the concepts are further described below in the detailed description. This summary is not intended to identify essential features of the claimed subject matter nor is it intended for use in determining or limiting the scope of the claimed subject matter.
[007] In one implementation, a system for routing a call through a network server is provided. The system comprises of a processor. The system further comprises of

a memory coupled to the processor. The processor is capable of executing a plurality of modules stored in the memory. The plurality of module comprises a reception module configured to receive profile of a subscriber, profile of the subscriber having contacts details associated with a terminating user in a communication device of the subscriber. The reception module further receives one or more subscriber selected preferences in one or more preference modes in the network server. The plurality of module further comprises a selection module configured to enable a selection of at least one preference mode by communicating with the communication device (User end device) of the subscriber. The plurality of modules further comprises a call routing module configured to identify profile of the subscriber and route the call from the communication device of the subscriber to the contact details of the terminating user with respect to the preference mode so selected.
[008] In one implementation, a method for routing a call through a network server is provided. The method comprises steps of receiving profile of a subscriber from a communication device of the subscriber, profile of the subscriber having one or more contact details associated with a terminating user, wherein the profile of the subscriber comprises one or more subscriber selected preferences in one or more preference modes in the network server. The method further comprises storing profile of the subscriber, the preference modes and preferences set by the subscriber. The method further comprises selecting the preference modes selection by communicating with communication device of the subscriber. The method further comprises routing the call by identifying profile of the subscriber to the contact details of the terminating user upon selection of the preference mode by the subscriber. The receiving, the storing, the selecting and the routing are performed by a processor.
[009] In one implementation, a system for session initiation in a communication device of a subscriber is provided. The system comprises of a processor. The

system further comprises of a memory coupled to the processor. The processor is capable of executing a plurality of modules stored in the memory. The plurality of module comprises a data storing module in communication with a system database is configured to store in the communication device of the subscriber, contact details associated with a terminating user. The plurality of module further comprises an updation module to update the contact details of the terminating user stored through a network server and to enable a selection of at least one preference modes by the communication device of the subscriber. The plurality of module comprises a session initiation module to initiate and route the call to the contact details of the terminating user based on the preference mode so selected by the subscriber. [0010] In one implementation, a method for session initiation in a communication device of a subscriber is provided. The method comprises storing contact details associated with the terminating user in the communication device of the subscriber. The method further comprises updating the contact details of the terminating user in a network server for enabling a selection of at least one preference modes by the communication device of the subscriber. The method further comprises initiating and routing call to the contact details of the terminating user based on the preference mode so selected by the subscriber. The storing, the updating, and the initiating are performed by a processor.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011 ] The detailed description is described with reference to the
accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawings to refer like features and components.

[0012] Figure 1 illustrates a network implementation of a system for routing
a call through a network server is shown, in accordance with an embodiment of the present subject matter.
[0013] Figure 2 illustrates the system for routing a call through a network
server, in accordance with an embodiment of the present subject matter.
[0014] Figure 3 illustrates a method for routing a call through a network
server, in accordance with an embodiment of the present subject matter.
[0015] Figure 4 illustrates a method for routing the call to contact number of
the terminating user, in accordance with an embodiment of the present subject matter.
[0016] Figure 5 illustrates the system for session initiation in a
communication device of a subscriber, in accordance with an embodiment of the present subject matter.
[0017] Figure 6 illustrates a method for session initiation in a communication
device of a subscriber, in accordance with an embodiment of the present subject matter.
[0018] Figure 7(a) and 7(b) illustrates a method implementing the priority
preference mode, in accordance with an embodiment of the present subject matter.
[0019] Figure 8 illustrates SIP call flow for priority preference mode in IMS,
in accordance with an embodiment of the present subject matter.
[0020] Figure 9(a) and 9(b) illustrates a method implementing the economy
preference mode, in accordance with an embodiment of the present subject matter.
[0021] Figure 10 illustrates SIP call flow for economy preference mode in
IMS, in accordance with an embodiment of the present subject matter.

[0022] Figure 11 illustrates SIP call flow for call mode feature rejection, in
accordance with an embodiment of the present subject matter.
DETAILED DESCRIPTION OF THE INVENTION
[0023] Systems and methods for routing a call through a network server are
described. The network server stores a subscriber profile comprising contact information and updates the subscriber profile when the subscriber makes any changes. The subscriber profile consists of the terminating user's contact numbers stored under a unique name within the subscriber's contact list, wherein the terminating user may further have one or more contact numbers associated with the terminating user. The subscriber sets preferences based on the priority preference mode and economy preference mode in the network server. Further, the network server communicates with a communication device in order to receive selection of the preference mode. Upon receiving the selection of preference mode, the corresponding logic and its functioning for either of the preference mode was invoked in the network server that routes the call to the contact number of the terminating user by identifying the profile of the subscriber.
[0024] Further, systems and methods for session initiation in a
communication device of a subscriber are described. The communication device stores one or more contact details under a unique name within the subscriber's contact list of the terminating user. The contact details stored in the communication device is updated in the network server and preference modes are further selected using the communication device by the subscriber. The preference modes may be preset by the subscriber and consist of a priority preference mode and an economy preference mode. A session is initiated in order

to place a call and to route the call to one of the contact details of the terminating user based on the preference modes that are predefined or preset.
[0025] The call is routed depending upon the preference mode selection by the subscriber. The call is routed to the contact details of the terminating user. In case the subscriber selects the priority preference mode, the network server enables the selection of contact number of the terminating user with respect to a predefined list with priority of called number stored in the network server as subscribed by the subscriber. Further, in case the subscriber selects the economy preference mode, the network server enables the selection of the terminating user contact number based on analyzing the subscriber tariff plan by the network server and the least tariff cost yielding the terminating user's contact number is selected.
[0026] While aspects of described system and method for routing a call in a
network server may be implemented in any number of different computing systems, environments, and/or configurations, the embodiments are described in the context of the following exemplary system.
[0027] Referring now to Figure 1 and Figure 2, a network implementation
100 of a system 102 for routing a call through a network server 150 is illustrated, in accordance with an embodiment of the present subject matter. In one embodiment, the system 102 stores a subscriber profile with the contact numbers list and updates the subscriber database whenever the subscriber makes any change. The subscriber profile consists of a terminating user's contact numbers wherein the terminating user may further have one or more contact numbers associated with the terminating user. The system 102 stores preference modes set by the subscriber, the preference mode includes priority preference mode and economy preference mode.

[0028] The system 102 receives selection of preference mode by the
subscriber using the communication device 500, the system 102 routes the call by identifying the profile of the subscriber. The call is routed depending upon the preference mode selection by the subscriber. The call is routed to the contact details of the terminating user.
[0029] Although the present subject matter is explained by considering a
scenario that the system 102 is implemented as an application on a server it may be understood that the system 102 may also be implemented in a variety of computing systems, such as a laptop computer, a desktop computer, a notebook, a workstation, a mainframe computer, a server, a network server, any type of call routing switch (VoIP or PSTN) and the like. It will be understood that the system 102 may be accessed by multiple users through one or more user devices 104-1, 104-2... 104-N, collectively referred to as user devices 104 hereinafter, or applications residing on the user devices 104. Examples of the user devices 104 may include, but are not limited to, a portable computer, a personal digital assistant, a handheld device, and a workstation. The user devices 104 are communicatively coupled to the system 102 through a network 106.
[0030] In one implementation, the network 106 may be a wireless network, a
wired network, an IP Multimedia Systems, a Long Term Evolution access networks, next generation networks or a combination thereof. The network 106 can be implemented as one of the different types of networks, such as intranet, local area network (LAN), wide area network (WAN), the internet, and the like. The network 106 may either be a dedicated network or a shared network. The shared network represents an association of the different types of networks that use a variety of protocols, for example, Hypertext Transfer Protocol (HTTP), Transmission Control Protocol/Internet Protocol (TCP/IP), Wireless Application Protocol (WAP), and the like, to communicate with one another. Further the

network 106 may include a variety of network devices, including routers, bridges, servers, computing devices, storage devices, and the like.
[0031] Referring now to Figure 2, the system 102 is illustrated in accordance
with an embodiment of the present subject matter. In one embodiment, the system 102 may include at least one processor 202, an input/output (I/O) interface 204. and a memory 206. The at least one processor 202 may be implemented as one or more microprocessors, microcomputers, microcontrollers, digital signal processors, central processing units, state machines, logic circuitries, and/or any devices that manipulate signals based on operational instructions. Among other capabilities, the at least one processor 202 is configured to fetch and execute computer-readable instructions stored in the memory 206.
[0032] The I/O interface 204 may include a variety of software and hardware
interfaces, for example, a web interface, a graphical user interface, and the like. The I/O interface 204 may allow the system 102 to interact with a user directly or through the client devices 104. Further, the I/O interface 204 may enable the system 102 to communicate with other computing devices, such as web servers and external data servers (not shown). The I/O interface 204 can facilitate multiple communications within a wide variety of networks and protocol types, including wired networks, for example, LAN, cable, etc., and wireless networks, such as WLAN, cellular, or satellite. The I/O interface 204 may include one or more ports for connecting a number of devices to one another or to another server.
[0033] The memory 206 may include any computer-readable medium known
in the art including, for example, volatile memory, such as static random access memory (SRAM) and dynamic random access memory (DRAM), and/or nonvolatile memory, such as read only memory (ROM), erasable programmable

ROM, flash memories, hard disks, optical disks, and magnetic tapes. The memory 206 may include modules 208 and data 230.
[0034] The modules 208 include routines, programs, objects, components,
data structures, etc., which perform particular tasks or implement particular abstract data types. In one implementation, the modules 208 may include a reception module 210, a data storing module 212, a selection module 214, a call routing module 216, a data charging module 217 and other modules 218. The other modules 218 may include programs or coded instructions that supplement applications and functions of the system 102.
[0035] The data 230. amongst other things, serves as a repository for storing
data processed, received, and generated by one or more of the modules 208. The data 230 may also include a system database 232 and other data 234. The other data 234 may include data generated as a result of the execution of one or more modules in the other modules 218.
[0036] In one embodiment of the invention, referring to figure 2 and figure 3,
the system 102 comprises the reception module 210 configured to receive profile of a subscriber (step 302), the profile of the subscriber comprises contact details associated with a terminating user in a communication device 500 of the subscriber. The reception module receives one or more preferences in one or more preference modes in the network server 150 set by the subscriber. The contact details may further comprise of name details of the terminating user or plurality of contact numbers details of the terminating user or a combination of both. The preference modes set by the subscriber may further comprise a priority preference mode and an economy preference mode.
[0037] The network server 150 may comprise Home Subscriber Server,
Home Location Register or other server comprising network architecture such as PSTN, LTE and IPMS. Further, the communication device 500 may comprise

mobile phone, land phone, pager, PDA, Voice over Internet Protocol (VoIP) device. Softphone, Session Initiation Protocol (SIP) phone.
[0038] In one embodiment, the system 102 in the network server 150 comprises the data storing module 212 in communication with the system database 232 to store profile of the subscriber (step 304), the preference modes and the preferences of the subscriber. The data storing module 212 in communication with the system database 232 stores the priority of the contact details the subscriber sets for the terminating user contact numbers in the order of preferences as defined by the subscriber.
[0039] For example, the priority preference mode may comprise the prioritized list which may include list of contact numbers associated with the terminating user. The contact numbers may be ranked from a highest priority to a lowest priority as decided by the subscriber or user. In one exemplary embodiment, the subscriber may assign the relative priority to plurality of the contact numbers. The subscriber may assign highest priority to the contact number e.g. mobile phone number for which the terminating user is more likely to respond to the call. Similarly, the subscriber may assign a relative priority to one or more contact numbers that are remaining with respect to the terminating user.
[0040] Further, the subscriber may have mobile phone number, work phone number, home phone number associated with the terminating user in the communication device 500 of the subscriber. Out of these numbers, the mobile phone number may be the one for which the terminating user is most likely to respond and the work phone number and the home phone number may include those numbers for which the terminating user is least likely to respond. As described, the subscriber may assign the highest priority to the mobile phone number, a medium priority to the work phone number or set high priority to the terminating user's office landline on a weekday and a least priority to the home phone number. Assigning priority preference mode based on likelihood of getting response from the

terminating user is well understood by those skilled in the art and assigning priorities relative to priorities of the contact number associated with the terminating user in other manner is within the scope of the invention.
[0041] Jn one embodiment, the system 102 comprises the data storing module 212 in communication with the system database 232 to store profile of the subscriber as per the economy preference mode. The system 102 may further comprise a data charging module 217 configured to store and analyze charging plan associated with the terminating user contact numbers when the economy preference mode is selected as the preference mode. The data storing module 212 in communication with the system database 232 further fetches the data charging plans of the subscriber from the data charging module 217 and one or more contact numbers associated with the particular terminating user. In one exemplary embodiment, the data storing module 212 in communication with the system database 232 may store plurality of telecommunication operators and associated charging rates for the call made to respective terminating users.
[0042] The system 102 may facilitate in storing and analyzing the charging plans according to each contact number associated with the terminating user. The economy preference mode may be determined for particular terminating user depending on similar telecommunication operator, low cost charging plan, waived tariff rate for a particular operator, the time of the day, free minutes offered by the telecommunication operator for any given contact number etc. Further, the data charging module 217 may store charging plan information related to free calls to one or more contact numbers of the terminating user, applicable charges to each contact number of the terminating user, etc. for the subscriber. In one embodiment, when the subscriber initiates the call with economy preference mode to the terminating user, best possible charging plan is selected dynamically and contact number corresponding to the least charging plan is dialed.

[0043] In one embodiment, the communication device 500 of the subscriber updates the contact details of the subscriber with respect to the preferences to the network server 150 in real-time or statically.
[0044] In one embodiment, the system 102 comprises the selection module 214 configured to enable a selection of at least one preference mode by communicating with the communication device 500 of the subscriber. The selection module 214 receives the preference mode selection by the subscriber using the communication device 500 and transmits the subscriber preference mode (step 306) to the network server 150 in order to select the contact number to be dialed according to preferences set by the subscriber based on preference mode.
[0045] In one embodiment, the system 102 comprises the call routing module 216 configured to identify profile of the subscriber and route the call from the communication device 500 of the subscriber (step 308) to the contact detail of the terminating user with respect to the preference mode so selected. The call routing module 216 may be further configured to select the contact details as per the selection of the priority preference mode and route the call to the contact detail so selected, such that the selection of the priority preference mode enables the selection of the terminating user contact number with respect to a pre-defined list stored in the data storing module 212 in communication with the system database 232 as subscribed by the subscriber with the network server 150.
[0046] The call routing module 216 may be further configured to select the contact details as per the selection of economy preference mode and the call may be routed to the contact detail so selected, such that selection of economy preference mode further enables a selection of the terminating user contact number based on analyzing the subscriber charging plan from the data charging module 217 by the network server 150 and the least tariff cost yielding the terminating user contact number is selected.

[0047] In one embodiment, as illustrated in figure 4, the call routing module 216 places the call to the first contact number of the terminating user (step 402) from the preference contact number based on the preference mode. Further, the call routing module 216 routes the call to the next contact number of the terminating user (step 404), from the preference contact numbers when the first contact number is not answered or not reached or not active or failed for any other reason at the terminating user end.
[0048] Referring now to Figure 1 and figure 5, the network implementation
100 of a system 502 for session initiation in the communication device 500 of the subscriber is illustrated, in accordance with one embodiment of the present subject matter. In one embodiment, the system 502 stores a subscriber profile comprising the terminating user contacts and update the subscriber profile when the subscriber makes any change in the communication device 500. The changes made in the communication device 500 are updated in the network server 150 in a periodic manner or at regular time intervals. The subscriber profile consists of a terminating user contact numbers wherein the terminating user may further have one or more contact numbers associated with the terminating user. The system 502 stores the preference modes set by the subscriber, the preference mode includes priority preference mode and economy preference mode.
[0049] The communication device 500 facilitates in selection of the
preference mode by the subscriber, the system 502 routes the call by identifying the profile of the subscriber. The call is routed depending upon the preference mode selection by the subscriber. The system 502 sends a session initiation message to the network server 150 using the network 106. The INVITE method comprises messages defined in RFC such as the subscriber and the terminating user information, route information, media information etc. The system 502 may further comprise "Call-Mode" header having parameters "economy" or "priority" depending on the preference mode selection to invoke the logic and selection of

the terminating user contact number accordingly by the network server 150. Further, the system 502 may comprise the "Call-Mode" included in the "Supported" header to denote the same feature is supported by the system 502. Based on the mode the terminating user number is selected and the call is routed to the contact details of the terminating user.
[0050] Although the present subject matter is explained by considering a
scenario that the system 502 is implemented as an application on the communication device 500. It may be understood that the system 502 may also be implemented in a variety of computing systems, such as a laptop computer, a desktop computer, a notebook, a workstation, a mainframe computer, a server, and the like. The user devices 104 are communicatively coupled to the network server 102 through a network 106.
[0051] Though the present subject matter is explained by considering a
scenario that the system 502 is implemented using session initiation protocol as one of the medium of communication between the communication device 500 and network server 150 it is also applicable in general to other futuristic networks, media types (for any type of calls like example voice, video, data, fax etc) and solutions
[0052] Referring now to Figure 5, the system 502 is illustrated in accordance
with an embodiment of the present subject matter. In one embodiment, the system 502 may include at least one processor 602, an input/output (I/O) interface 604, and a memory 606. The at least one processor 602 may be implemented as one or more microprocessors, microcomputers, microcontrollers, digital signal processors, central processing units, state machines, logic circuitries, and/or any devices that manipulate signals based on operational instructions. Among other capabilities, the at least one processor 602 is

configured to fetch and execute computer-readable instructions stored in the memory 606.
[0053] The I/O interface 604 may include a variety of software and hardware
interfaces, for example, a web interface, a graphical user interface, and the like. The I/O interface 604 may allow the communication device 500 to interact with a user directly or through the client devices 104. Further, the I/O interface 604 may enable the communication device 500 to communicate with other computing devices, such as web servers and external data servers (not shown). The I/O interface 604 can facilitate multiple communications within a wide variety of networks and protocol types, including wired networks, for example, LAN, cable, etc., and wireless networks, such as WLAN, cellular, or satellite. The I/O interface 604 may include one or more ports for connecting a number of devices to one another or to another server.
[0054] The memory 606 may include any computer-readable medium known
in the art including, for example, volatile memory, such as static random access memory (SRAM) and dynamic random access memory (DRAM), and/or nonvolatile memory, such as read only memory (ROM), erasable programmable ROM, flash memories, hard disks, optical disks, and magnetic tapes. The memory 606 may include modules 608 and data 630.
[0055] The modules 608 include routines, programs, objects, components,
data structures, etc., which perform particular tasks or implement particular abstract data types. In one implementation, the modules 608 may include a data storing module 610, an updation module 612, a session initiation module 614, and other modules 616. The other modules 616 may include programs or coded instructions that supplement applications and functions of the communication device 500.

[0056] The data 630, amongst other things, serves as a repository for storing
data processed, received, and generated by one or more of the modules 608. The data 630 may also include a system database 632 and other data 634. The other data 634 may include data generated as a result of the execution of one or more modules in the other modules616.
[0057] In one embodiment, referring to figure 1, 5 and 6, the system 502 in the communication device 500 comprises the data storing module 610 in communication with the system database 632 configured to store one or more contact details associated with the terminating user (step 702) in the communication device 500 of the subscriber. The contact details may further comprises of name details and contact number details of the terminating user.
[0058] The communication device 500 may comprise mobile phone, land phone, pager, PDA, Voice over Internet Protocol (VoIlP) device, Softphone, Session Initiation Protocol (SIP) phone.
[0059] In one embodiment, the system 502 in the communication device 500 comprises the updation module 612 to update the contact details of the terminating user (step 704) stored in the system 502 in the communication device 500 and to enable a selection of at least one preference modes by the communication device 500 of the subscriber. The contact names and contact numbers of the terminating user from the communication device 500 of the subscriber are updated in the network server 150 in real-time or statically. The preference modes may comprise the priority preference mode and the economy preference mode.
[0060] In one embodiment, the system 502 in the communication device 500 comprises the session initiation module 614 configured to initiate and route the call to the contact details of the terminating user (step 706) based on the

preference mode so selected by the subscriber. Session initiation of the call from the communication device 500 to the network server 150 is performed using a Session Initiation Protocol (SIP). Routing the call upon initiation of the call using Session Initiation Protocol (SIP) is one means of session initiation and should not betaken in limited sense.
[0061] In one embodiment, the communication device 500 comprises a call mode header (not shown) in communication with the network server 150. Further, the call mode header may be present in Session Initiation protocol (SIP). Use of call mode in Session Initiation protocol (SIP) is one means and should not be taken in limited sense. The call mode header may comprise the economy preference mode and the priority preference mode in SIP. Further, the system 502 may comprise "186 response" which facilitates call progress with call rejection. The "186 response" is explained with the help of exemplary embodiment. Further, multiple TO headers may be presented to send the terminating user contact numbers along with the call mode in order to implement the priority preference mode and the economy preference mode in the communication device 500 using SIP. The multiple TO headers may be presented with the preference mode to list different contact numbers of the terminating user to the network server 150. The "q" parameter value associated with each TO header number may be used by the subscriber to set and may also change the priority of the terminating user contact number. This is received and analyzed by the network server 150 to route the call dynamically.
[0062] The implementation of the priority preference mode and the economy preference mode is illustrated with an exemplary embodiment. Consider originating Internet Service Provider (ISP) as the subscriber ISP placing the call using communication device 500 and terminating ISP as the terminating user ISP.

[0063] The subscriber stores contact details of the terminating user in the system 502 of the communication device 500. The subscriber updates the contact details in the system 102 of the network server 150 in the data storing module 212 in communication with the system database 232 by utilizing the JSP. In case of any modification or deletion or addition to any of the contact details associated with the terminating user, the same is updated to the network server 150 using the updation module 612 in the ISP. When the subscriber selects the call mode in order to place the call to the terminating user, the subscriber may have to choose the call mode dynamically each time when the subscriber dials the contact number of the terminating user.
[0064] If the network server 150 does not comprise the profile of the subscriber in the ISP, then the subscriber may have to transmit all the contact details of the terminating user in multiple TO headers that may contain the terminating user numbers based on INVITE method in order to implement the call mode feature. The subscriber may have to transmit and update the contact details of the terminating user along with the preferences based on the priority preference mode and the economy preference mode.
[0065] For the purpose of illustration, consider the subscriber storing the contact details of the terminating user e.g. Bob in the communication device 500 and the network server 150 as shown in Table. 1. Economy Ranks may be stored based on the subscriber charging plan. The economy ranks may be calculated and stored by the network server 150 as the subscriber contact database. The network server 150 eliminates the redundant logic of the economy rank calculation being arrived each time when a call is initiated by the subscriber to the terminating user. The economy ranks may be recalculated and stored when there is any modification in the subscriber charging plan or when changes are made to the terminating user contact number. The priority ranks may be stored based on the highest and least

priority depending on the likelihood of the terminating user responding to the call. The priority ranking may be maintained by the subscriber statically.

Network server: Subscriber
Primary com tact name: Bob
User Phone Type User Numbers Priority Economy Rank Time
Mobile 1 B-MI 1 3
Home - Landlinel B-HL1 5 2
Office-Landline 1 B-OL1 3 2 0800 to l700Hrs (Weekday)
Mobile 2 B-M2 2 1
Office - Landline2 B-OL2 4 4 0800 to 1700 Hrs
(Weekday)
Table.1
[0066] Considering the above table, the subscriber has more than one contact details for the terminating user i.e., Bob. The terminating user may be reached at office landline number, residential landline number, multiple mobile numbers etc. The contact details of the terminating user is stored in the data storing module 610 in communication with the system database 632, in the communication device 500 and the contact details are updated to the data storing module 212 in communication with the system database 232 in the network server 150. In one embodiment, the network server 150 may comprise home subscribe server (HSS). The contact details present in the communication device 500 may be updated in the network server 150 in HSS maintained by the ISP. Further, any modification or deletion or addition to any of the contact details associated with the terminating user is updated to the network server 150.

[0067] Referring now to Figure 7, 8, 9, 10 and 11 methods 800 and 900 for routing a call are shown, in accordance with embodiments of the present subject matter. The methods 800 and 900 may be described in the general context of computer executable instructions. Generally, computer executable instructions can include routines, programs, objects, components, data structures, procedures, modules, functions, etc., that perform particular functions or implement particular abstract data types. The methods 800 and 900 may also be practiced in a distributed computing environment where functions are performed by remote processing devices that are linked through a communications network. In a distributed computing environment, computer executable instructions may be located in both local and remote computer storage media, including memory storage devices.
[0068] The order in which the methods 800 and 900 are described is not
intended to be construed as a limitation, and any number of the described method blocks can be combined in any order to implement the methods or alternate methods. Additionally, individual blocks may be deleted from the methods without departing from the spirit and scope of the subject matter described herein. Furthermore, the methods can be implemented in any suitable hardware, software, firmware, or combination thereof. However, for ease of explanation, in the embodiments described below, the methods 800 and 900 may be considered to be implemented in the above described system 102 and 502 respectively.
PRIORITY PREFERENCE MODE
[0069] By considering example as shown in Table. 1, the priority preference mode is illustrated referring to Figure 7(a) and (b) as explanation of method 800.
[0070] When the subscriber places the call to the terminating user, Bob, upon the subscriber selects priority preference mode in the Call-Mode header, the call is routed in the ISP. Referring to Figure 7a and b, the subscriber initiates the call (step 802) using the communication device 500 with the call mode as the priority

preference mode. The communication device 500 of the subscriber sends INVITE comprising the mode as priority preference (step 804) to the network server 150. Originating Call Session Control Function (CSCF), in one embodiment is similar to the Call Routing Module 216, verifies the call mode header (step 806) and then checks in the data storing module 212 in communication with the system database 232 of the network server 150 for the preferences defined by the subscriber with respect to the terminating user, Bob. Originating CSCF communicates with HSS in order to fetch the subscriber profile (step 808). If the subscriber has subscribed (step 810) to the call mode feature, the TO header is checked for its domain name (step 816). Upon checking for the domain name, the CSCF gets the terminating user, Bob's contact details from the subscriber network server (step 822). The CSCF facilitates in routing the call to the contact number which has highest priority that has been preferred by the subscriber (step 824).The session initiation module 614 in the communication device 500 initiates the call to the contact number (step 826) of the terminating user having highest priority. If the terminating user answers the call (step 828) from the subscriber, the process ends (step 838).
[0071] In one exemplary embodiment, the CSCF determines the priority preference by fetching the p re-con figured priority preferences set by the subscriber. If the priority preferences are not available in the network server 150, then the subscriber may set the priority preference dynamically and send it through the INVITE message using the q parameter value. Further, the priority preference set dynamically by the subscriber in the INVITE method may have more precedence in the network server 150 than the preference stored in the network server 150.
[0072] If the subscriber has subscribed to the call mode feature, when the TO header is checked for its domain name and the domain name is not present but the multiple terminating user numbers present in multiple TO header (step 818) then the terminating user numbers are fetched from each TO headers available in the

INVITE message sent by the communication device 500 to network server 150. In case if there is no domain name and no multiple TO header for the terminating user and there is no contact stored for the terminating user in network server 150 then the call is processed with only available contact number (step 820) sent from the communication device 500. . Further, when multiple TO header is present, the CSCF gets all the terminating user contact details from the TO header (step 830) and the CSCF facilitates in routing the call to the contact number which has highest priority that has been preferred by the subscriber.
[0073] In case where the terminating user does not answer the call, the system 102 waits for predetermined time (step 834), for example, three rings, and checks whether all the other terminating user contact numbers were tried or not (step 836). Based on this result, the next priority contact number is dialed (step 832) by the system 102 incase when the first priority number was not answered, the process mentioned in step 832. 834 and 836 continues until the terminating user answers the call or the available terminating user contact numbers were tried at least once.
[0074] The INVITE received from the subscriber may have call mode as priority preference and upon receiving the INVITE, the CSCF sets the call mode for any given call to priority preference and CSCF retrieves the subscriber profile from HSS. The exemplary INVITE method from the subscriber may be presented as shown below:
INVITE sip:userBmobile@operatorX.com> SIP/2,0
Via: SIP/2.0/UDP localdomain.com;branch=z9hG4bK123456
Supported: timer,path,100rel.Call-Mode
Max-Forwards: 70
Call-Mode: Priority
To: userB
To: userB ;q=0.6
From: userA ;tag=l 2345678

Call-ID: 123456@localdomain.com CSeq: 1 INVITE
Contact: Content-Type: application/sdp Content-Length: 100
[0075] The greater the "q" value, higher is the priority for that number in the TO header. If the subscriber dynamically alters the priority then the priority is modified by changing the "q" value for that number by keeping high "q" value with maximum being 1, the modification may be performed in the INVITE message sent from communication device 500.
[0076] If the subscriber is not subscribed to the call mode feature, but tries to invoke this preference based calling then the subscriber is presented with error message through new "186 response" (step 812) and the call is initiated to the first available number received in the TO header (step 814). In one embodiment, the error message is presented to the subscriber at display of the communication device 500 as call-mode rejection. The error message may be displayed in the form of a text message or an audio voice response informing the rejection in the communication device 500.
[0077] In another exemplary embodiment, referring to Figure 8, implementation of the Session Initiation Protocol (SIP) call flow for priority preference mode is explained in IMS architecture. If the terminating user answers the call, then the call is released upon completion of the call between the subscriber and the terminating user. If the contact number of the terminating user is not answered after pre-configured time, the call is released. The call release upon the terminating user not answering is facilitated by CANCEL method sent from the CSCF to the terminating user. The CSCF implements the logic of priority preference upon the terminating user not answering the first priority contact number present in the contact details of the subscriber.

[0078] As shown in Figure 7a and b and Figure 8 and referring Table 1, depending on the preferences set in the priority preference mode of the subscriber and upon executing the priority preference mode request, the terminating user contact number B-Ml may be chosen. If the terminating user does not answer the call by the subscriber B-Ml for the reasons such as not reachable, no answer, server error, client error etc., the next contact number in the Table. 1 may be selected and the contact number is dialed.
ECONOMY PREFERENCE MODE
[0079] Considering example as shown in Table. 1, the economy preference mode is illustrated referring to Figure 9a and 9b as explanation of method 900.
[0080] When the subscriber places the call to the terminating user, Bob, upon the subscriber selects economy preference mode in the Call-Mode header, the call is routed in the ISP. The economy preference mode is selected by the subscriber to call the terminating user when the subscriber wishes to utilize the cheapest tariff from the ISP for all the calls. Referring to Figure 9a and 9b the subscriber initiates the call in the communication device 500 with the call mode as the economy preference mode (step 902). The communication device 500 of the subscriber sends INVITE comprising the mode as economy preference (step 904) to the network server 150. The originating CSCF i.e., call routing module 216 verifies the call mode header and checks (step 906) in the data storing module 212 in communication with the system database 232 of the network server 150 for the preferences defined by the subscriber with respect to the terminating user, Bob. Originating CSCF communicates with HSS in order to fetch the subscriber profile and charging plans (step 908) associated with the contact numbers of the terminating user. If the subscriber has subscribed to the call mode (step 910) feature, the CSCF fetches the subscriber charging plans from the HSS i.e., data

charging module 217 (step 916). The TO header is checked for its domain name (step 918). Upon checking for the domain name, the CSCF gets the terminating user, Bob's contact details from the subscriber (step 924) network server 150. The CSCF checks for the cheapest call among the contact numbers available with respect to the terminating user (step 926) using the subscriber charging plan and initiates the cheapest call. The call routing module 216 routes the call to the contact number of the terminating user (step 928) having cheapest tariff from the communication device 500 of the subscriber. If the terminating user answers the call (step 930) from the subscriber, the process ends (step 940).
[0081] The exemplary INVITE method from the subscriber for the economy preference mode may be presented as shown below:
INVITE sip:userB@remotedomain.com SIP/2.0
Via: SIP/2.0/UDP localdomain.com;branch=z9hG4bK123456
Supported: timer,path,l00rel.Call-Mode
Max-Forwards: 70
Call-Mode: Economy
To: userB
From: userA;tag=l2345678
Call-ID: 123456@localdomain.com
CSeq: 1 INVITE
Contact:
Content-Type: application/sdp
Content-Length: 100
[0082] In one exemplary embodiment, the CSCF determines the economy preference mode by fetching the charging plan of the subscriber and arriving at the lowest economy rank for each of the contact numbers of the terminating user. The

economy rank may be obtained as showed in Table 1 after the calculation is performed by the network server 150 and is not set by the subscriber.
[0083] If the subscriber has subscribed to the call mode feature, when the TO header is checked for its domain name and the domain name is not present and also there may be no multiple TO header present (step 920) then the call is processed with only available contact numbers (step 922) in the network server 150. Further, when multiple TO header is present, the CSCF gets all the terminating user contact details from the TO header, arrives at the economy rank for each of the terminating user contact numbers after analyzing the charging plan of the subscriber and the CSCF facilitates in routing the call to the contact number which has cheapest tariff as per economy preference that has been preferred by the subscriber.
[0084] In case where the terminating user does not answer the call, the system 102 waits for predetermined time (step 936), for example, three rings, and checks for all the terminating user contact numbers which have not been tried till then (step 938) and routes the call to the next economy rank number (step 934). In case when the best economy number is not answered, the next cheapest available contact number is dialed by the system 502 until the terminating user answers the call.
[0085] If the subscriber is not subscribed to the call mode feature, then the subscriber is presented with error message the "186 response" (step 912) and the call is initiated to the first available number received in the TO header (step 914). In one embodiment, the error message is presented to the subscriber at display of the communication device 500 as call-mode rejection. The error message may be displayed as a text message or as an audio voice response informing the rejection in the communication device 500.
[0086] Referring to Figure 10, illustrates the SIP call flow implementation of economy preference mode in IMS architecture. When the subscriber dials the

terminating user, the CSCF sends the INVITE method in SIP with a new header Call-Mode as economy preference mode. [0087] From the Figure 9 and 10, for example, depending on the charging plan of the subscriber and upon implementing the economy preference mode, the contact number of the terminating user to be called chosen is B-M2. If the contact number B-M2dialed is not answered due to the reasons such as not reachable, no answer, server error,.client error, etc., the remaining contact numbers may be dialed according to Table 1, B-OL1 may be selected and dialed.
186 RESPONSE - CALL MODE FEATURE REJECTION
[0088] The call mode rejection feature and handling of the call in IMS using SIP may be explained by referring to Figure II. From the profile CSCF will check whether the subscriber has subscribed to this feature or not. In case of missing subscription a provisional error response "186: Call Progress with Call-Mode Rejection" may be sent to the communication device 500 of the subscriber. The error message may be presented to the subscriber at display of the communication device 500 as call-mode rejection. The error message may be displayed also as a text message or an audio voice response informing the rejection in the communication device 500.
[0089] Although the various embodiments describe implementation of the preference modes in SIP protocol, the preference modes may also be implemented in a Voice over Internet Protocol (VoIP) call and such implementation in any other protocols should be obvious and within the scope of the embodiments described herein. The subscriber may initiate the call to contact the terminating user. The SIP-INVITE message may be sent to the ISP via broadband network.
[0090] The written description describes the subject matter herein to enable any person skilled in the art to make and use the embodiments of the invention. The

scope of the subject matter embodiments is defined by the claims and may include other modifications that occur to those skilled in the art. Such other modifications are intended to be within the scope of the claims if they have similar elements that do not differ from the literal language of the claims or if they include equivalent elements with insubstantial differences from the literal language of the claims.

I/WE CLAIM:
1. A system for routing a call through a network server, the system comprising:
a processor; and
a memory coupled to the processor, wherein the processor is capable of executing a plurality of modules stored in the memory, and wherein the plurality of modules comprising:
a reception module configured to receive a profile of a subscriber, the profile of the subscriber comprises contacts details associated with a terminating user, and wherein the profile is stored in a communication device of the subscriber, further, the reception module receives one or more subscriber selected preferences in one or more preference modes associated with the profile of the subscriber, in the network server;
a selection module configured to enable a selection of at least one preference mode by communicating with the communication device of the subscriber; and
a call routing module configured to identify the profile of the subscriber and route the call from the communication device of the subscriber to the contacts details of the terminating user with respect to the preference mode so selected.
2. The system of claim 1, wherein the contact details further comprises name details of the terminating user or plurality of contact numbers details of the terminating user or combination of both.
3. The system of claim 1, wherein the preference modes further comprises a priority preference mode and an economy preference mode.
4. The system of claim 1, the system further comprises a data storing module configured to communicate with a system database to store profile of the subscriber, the preference modes and preferences of the subscriber.

5. The system of claim 1, the system further comprises a data charging module configured to store and analyze charging plan associated with the terminating user contact numbers when the economy preference mode is selected as the preference mode.
6. The system of claim 1, wherein the call routing module is further configured to select the contacts details as per the selection of the priority preference mode and route the call to the contact detail so selected, such that the selection of the priority preference mode enables the selection of terminating user contact number with respect to a pre-defined list stored in the storing module as subscribed by the subscriber with the network server.
7. The system of claim 1, wherein the call routing module is further configured to select the contacts details as per the selection of economy preference mode and the call to the contact detail so selected, such that selection of economy preference mode further enables a selection of terminating user contact number based on analyzing the subscriber tariff plan by the network server and the least tariff cost yielding terminating user contact number is selected.
8. The system of claim 1, wherein the communication device comprises mobile phone, land phone, pager, PDA, Voice over Internet Protocol (VoIP) device, Softphone. Session Initiation Protocol (SIP) phone.
9. The system of claim 1, wherein the network server comprises Home Subscriber Server, Home Location Register, other architectures such as PSTN, LTE and IPMS.
10. The system of claim 1, wherein the data storing module further fetches the data charging plans of corresponding contact details of the terminating user from a

telecom operator of one or more contact numbers associated with the terminating user.
11. A method for routing a call through a network server, the method comprising:
receiving profile of a subscriber from a communication device of the subscriber, the profile of the subscriber storing contacts details associated with a terminating user, wherein the profile of the subscriber is associated with one or more subscriber selected preferences in one or more preference modes in the network server;
selecting the preference modes by communicating with communication device of the subscriber;
routing the call by identifying profile of the subscriber to the contact detail of the terminating user upon selection of the preference mode by the subscriber.;
wherein the receiving, the storing, the selecting and the routing are performed by a processor.
12. The method of claim 11, wherein the contact details further comprises of name details and contact number details of the terminating user.
13. The method of claim 11. wherein the preference modes comprises of a priority preference mode and an economy preference mode.
14. The method of claim 11, wherein routing the call further comprises of selecting the contact details as per the selection of the priority preference mode and route the call to the contact detail so selected, such that the selection of the priority preference mode selects enables the selection of contact number of the terminating user with respect to a pre-defined list stored in the storing module as subscribed by the originating subscriber with the network server.

15. The method of claim 11, wherein the routing of the call is further configured to select the contact details as per the selection of economy preference mode and the call to the contact detail so selected, such that selection of economy preference mode further enables a selection of the terminating user contact number based on analyzing the subscriber tariff plan by the network server and the least tariff cost yielding terminating user contact number is selected.
16. The method of claim 11, wherein the preferences set include placing call in an order of the contact numbers of the terminating user depending on the preference mode so selected.
17. The method of claim 11, wherein routing the call to contact number of the terminating user further comprises:
placing the call to a first contact number of the terminating user from the preference contact number based on the preference mode; and
routing the call to a next contact number of the terminating user from the preference contact number when the first contact number is not answered by the terminating user.
18. A system for session initiation in a communication device of a subscriber, the
system comprising:
a processor; and
a memory coupled to the processor, wherein the processor is capable of executing a plurality of modules stored in the memory, and wherein the plurality of module comprising:

a data storing module in communication with a system database configured to store in the communication device of the subscriber, contact details associated with a terminating user;
an updation module to update the contact details of the terminating user stored in a network server and to enable a selection of at least one preference modes by the communication device of the subscriber; and
a session initiation module to initiate and route the call to the contact details of the terminating user based on the preference mode so selected by the subscriber.
19. The system of claim 18, wherein the contact details further comprises of name details and contact number details of the terminating user.
20. The system of claim 18, wherein the communication device comprises mobile phone, land phone, pager, PDA, Voice over Internet Protocol (VoIP) device, Softphone, Session Initiation Protocol (SIP) phone.
21. The system of claim 18, wherein the initiation of the call from the communication device to the network server is performed using a Session Initiation Protocol (SIP) as one means and not restricted only to this protocol.
22. The system of claim 18, the preference modes comprises of a priority preference mode and an economy preference mode.
23. The system of claim 18, wherein the contact names and contact numbers of the terminating user from the communication device of the subscriber are updated in the network server in real time or statically.
24. The system of claim 18, wherein the communication device comprises a call mode header in communication with the network server.

25. The system of claim 18, wherein the call mode header presented is in Session Initiation protocol (SIP).
26. A method for session initiation in a communication device of a subscriber, the method comprising:
storing contact details associated with a terminating user in the communication device of the subscriber;
updating the contact details of the terminating user in a network server for enabling a selection of at least one preference modes by the communication device of the subscriber; and
initiating and routing a call to the contact details of the terminating user based on the preference mode so selected by the subscriber;
wherein the storing, the updating, and the initiating are performed by a processor.
27. The method of claim 26, wherein the preference modes further comprises of a priority preference mode and an economy preference mode.
28. The method of claim 26, wherein the preferences set in the network server include placing call in an order of contact numbers depending on the preference mode.
29. The method of claim 26, wherein updating the contact names and contact numbers of the terminating user from the communication device of the subscriber in the network server are performed in real time or statically.