WO2001037529A1

WO2001037529A1 - Virtual pbx system

Info

Publication number: WO2001037529A1
Application number: PCT/US2000/031784
Authority: WO
Inventors: Thomas J. Galvin; Michael C. Kirchner; Anthony W. S. Moey; Mark J. O'brien; Joel K. Hanson
Original assignee: Mci Worldcom, Inc.
Priority date: 1999-11-17
Filing date: 2000-11-17
Publication date: 2001-05-25
Also published as: US7496091B2; US6775272B2; US20020114329A1; AU1779101A; CA2392161A1; EP1232640A1; US6393017B1; EP1232640A4; US20040160951A1; JP2003515284A

Abstract

A private branch exchange (PBX) (118) system that routes calls within a packet-switching network (106). Login information is received from a data device (102). The login information includes an alias identifying a user at the data device (102) and a network address identifying the location of the data device (102) on the packet-switching network (106). The virtual private branch exchange system associates the user's PBX (118) extension with the network address and routes calls to the user's PBX (118) extension to the data device (102) on the basis of the network address of the data device (102).

Description

VIRTUAL PBX SYSTEM

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates generally to a telephony system, and more specifically to

a virtual private branch exchange (PBX) system for a packet-switching network (PSN).

Discussion of the Background

A PBX is an automatic telephone switching system that enables users within an

organization to place calls to each other without having to access a public switched telephone

network (PSTN). Users can also place calls to outside numbers via the PBX. PBXs are

typically located on the premises of a customer and provide a great deal of control and

flexibility in the customer's communications. PBXs are well known and are described, for

example in Stallings, "Data and Computer Communications," 4^th Edition, MacMillan Publishing Co., New York, 1994, which is incorporated herein by reference.

One approach to implementing a PBX involves a virtual PBX call processing method

in which a packet switching system establishes a virtual circuit between each distinct pair of

user packet stations in a group. The user packet stations exchange signaling packets via the

virtual circuits and respond to such packets by coordinating the initiation and disconnection

of voice, data, or image calls. All call processing, including the provision of features, such as

call forwarding and automatic call back, is accomplished by the stations without the aid of the

switching system. Thus, all of the intelligence of the system is on the terminal side of the system and not on the network side. Consequently, telephony agents and terminals are

required to process inbound and outbound calls and perform routing. No dynamic tracking of

locations is performed by this system, and all of the terminal locations are static.

Methods of using Internet based communication standards for telephone

communication have been developed for use with conventional PBXs. These methods simply (1 ) permit remote telephone access to an existing PBX system via a PSTN and (2) link

Internet Protocol (IP) telephony clients to an existing PBX system via an H.323 gateway. H.323 is an ITU (International Telecommunications Union) standard that provides a set of

specifications for equipment and services for use with multimedia communications over a

network. An example of how IP telephony clients are linked to an existing PBX system via

an H.323 gateway is described in http://quicknet.net/support/AppNotcs/AN00004.htm, which

is incorporated herein by reference. However, such systems still incorporate a conventional

PBX, which handles call referencing and switching.

SUMMARY OF THE INVENTION

Accordingly, one object of this invention is to provide a virtual PBX system for a

packet-switching network (PSN), where the intelligence of the virtual PBX system is located

in the network rather than in the terminals.

It is another object of the present invention to provide a PBX system for a PSN that

does not require telephony equipment.

It is yet another object of the present invention to track locations of users of the virtual

PBX system in real time so that users are not required to maintain static locations. It is still yet another object of the present invention to track useis' locations for call

and message delivery each time a user connects to the PSN.

It is still a further object of the present invention to provide connectivity between the

virtual PBX system of the present invention and existing public switched telephone networks

(PSTNs) and existing PBX systems.

These and other objects are achieved according to the present invention by providing a

novel method, system, computer program product, and data structure in which login

information is received from a data device. The login information includes an alias

identifying a user at the data device and a network address identifying the location of the data

device on the PSN. The user's PBX extension is associated with the network address of the

data device, and calls are routed to the user's PBX extension to the data device on the basis of the network address of the data device. In this manner, a virtual PBX system for a PSN is

implemented. Advantageously, the intelligence of the virtual PBX system is located in the

network instead of in the terminals (e.g., the data device).

Preferably, information that uniquely identifies a user is linked to the user's PBX

extension. As a result, the virtual PBX system of the present invention does not require

conventional telephony equipment to route calls.

The location of the user can be dynamically tracked by storing the network address of

the data device when the user logs onto the PSN with the data device. If the user logs onto

and off of the PSN with different data devices, then the inventive virtual PBX system is able

to track the location of the user by dynamically storing the network address of the data device

that is currently connected to the PSN under the user's alias. When the user disconnects from

or logs off of the PSN, the virtual PBX system disassociates the network address of the data device that is being disconnected from the PBX extension of the user. Preferably, the

network address of the data device is an Internet Protocol (IP) address.

Additionally, known gateways provide connectivity between the virtual PBX system

of the present invention and existing PSTNs and existing PBX systems. Thus, the virtual

PBX system can complement, or be used independently qf, conventional telephony networks.

BRIEF DESCRIPTION OF THE DRAWINGS A more complete appreciation of the invention and many of the attendant advantages

thereof will be readily obtained as the same becomes better understood by reference to the

following detailed description when considered in connection with the accompanying

drawings, wherein:

Figure 1 is a schematic illustration of an embodiment of a virtual PBX system that

complements a standard telephony network;

Figure 2 is a drawing of an extension aliases record for associating each user's alias

with a group identification (ID) number and a user extension, utilized in the system of Figure

l;

Figure 3 is an extension locations record for associating a user's group ID number,

user extension, and sorting, in order of preference, various locations for each user to receive

calls, utilized in the system of Figure 1;;

Figure 4 is a packet network locations record for dynamically tracking and associating

the group ID number, the user extension, and the network address of users that are logged

onto the virtual PBX system of Figure 1 ; Figure 5 is a flow chart showing how a user logs onto the virtual PBX system of

Figure 1 ;

Figure 6 is a flow chart for explaining different user options that are available with the

virtual PBX system of Figure 1 ;

Figures 7 and 8 are flow charts explaining the process for making a call from the

virtual PBX system to another user via a conventional¹ PSTN or via the virtual PBX system;

Figure 9 is a flow chart explaining the process for receiving a call from an outside

user with the virtual PBX system of Figure 1; and

Figure 10 is a schematic diagram of a general purpose computer system that can be

programmed to perfoπn the special purpose function(s) of one of more of the devices shown

in the system of Figure 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings, wherein like reference numerals designate identical or

corresponding parts throughout the several views, and more particularly to Figure 1 thereof,

there is shown a virtual PBX system 100 that interfaces with a standard telephony network

1 16. The virtual PBX system 100 includes data devices 102 and 104, a packet-switching network 106, one or more processors 108, one or more object storage databases 1 10, one or

more directories 1 12, and one or more databases 1 14.

The data devices 102 and 104 can be personal computers, palmtop computers, laptop

computers, or any other terminal, endpoint, or device suitable for transmitting and receiving

data (e.g., voice data) over a packet-switching network (PSN). The data devices 102 and 104

preferably include microphones and speakers or other suitable equipment for sending and receiving voice messages over the packet-switching network 106. The data devices 102 and

104 may also be portable devices for wireless communication with the packet-switching

network 106 and for sending and receiving voice data over a PSN.

The data device 102 includes an agent 103, and the data device 104 includes an agent

105. The agents 103 and 105 are software (e.g., Web browser software) or circuitry for

allowing users to send and receive voice packets through the data devices 102 and 104,

respectively, to the packet-switching network 106. Such agents (also called telephony

agencies) are known. An example of an agent is MICROSOFT NETMEETING. Also,

agents are described in U.S. Pat. No. 5,867,494 to Krishnaswamy et al., entitled "System,

Method and Article of Manufacture With Integrated Video Conferencing Billing in a

Communication System Architecture," which is incorporated herein by reference. Preferably,

the agents 103 and 105 provide a graphical user interface for visually representing to a user various programs, files, and options for initiating and receiving calls, accessing user options,

and accessing message options, for example. User and message options are described below

in conjunction with Figure 6.

The packet-switching network 106 is any suitable network for relaying or transmitting

packets, such as the Internet, a portion of the Internet, a backbone network, a local area

network (LAN), or a wide area network (WAN). Packet-switching networks are known and

are described, for example, in Keiser and Strange, "Digital Telephony and Network

Integration," 2nd ed., Chapman & Hall, New York, 1 95, which is incorporated herein by

reference. The packet-switching network 106 connects the data devices 102 and 104 as well

as the processor 108 and the directory 1 12. Thus, the processor 108 and the directory 1 12

may form a portion of the packet-switching network 106. The packet-switching network 106 may operate independently of a conventional PSTN or, as shown in Figure 1, the packet-

switching network 106 can be interfaced to a PSTN through a gateway such as the packet

network telephony gateway 128.

The processor 108 is any device suitable for interpreting and executing instructions,

such as a general purpose computer, a server, or dedicated circuitry. The processor may also

be implemented with software such as Web server software that serves to clients (e.g., the

data devices 102 and 104) pages with information retrieved from the object storage database

1 10 and/or the directory 1 12, for example.

The processor 108 receives information regarding calls to be made to and from the

data devices 102 and 104. The information received includes information identifying

locations of users (e.g., IP addresses of the data devices 102 and 104, user's PBX extensions,

and/or e-mail addresses) and the telephone number and/or extensions of the originators of

outgoing calls and the recipients of incoming calls.

The processor 108 and the directory 1 12 may be implemented separately or on a

single computer, for example. In one embodiment, a single processor 108 is physically

separate and implemented separately from multiple directories 112, with each directory 112

corresponding to a group of customers. Preferably, the groups of customers are arranged

logically; for example, all of the users within a single company or other organization can be

organized into the same group. The processor 108 is configured to receive information from

the packet-switching network 106 and query the directory 1 12 for additional information,

based on the information that the processor 108 receives from the packet-switching network

106. The processor 108 includes, and/or communicates with, one or more object storage

databases 1 10. The processor 108 may communicate with the application call processing

(ACP) system 130 directly, as shown in Figure 1, or through a gatekeeper or other suitable

device for interfacing a packet-switching network and a conventional telephony network.

Other functions of the processor 108 may include, but are not limited to, controlling scripting,

receiving and processing acceptance codes (e.g., dual tone multi-frequency (DTMF) codes,

discussed in U.S. Pat. No. 5,787,150, for example), message and control handling (e.g.,

initiating and stopping recording of messages, tracking where messages are stored,

controlling user options, and controlling message options), serving as a proxy server to the

directory 1 12, processing communications to and from the ACP 130, querying the directory

1 12 for information, generating an alarm signal when errors in call processing are detected,

controlling redundancy if multiple directories 1 12 are used, and authenticating users who

wish to gain access to the virtual PBX system 100. Additionally, the processor 108

automatically stores billing information for various customers, generates billing reports at

specified time mtervals for each customer, and delivers the billing reports to respective of the

customers.

The object storage databases 1 10 store, organize, and sort information for the users of

the virtual PBX system 100. The information stored in the object storage database 110

includes voice messages, e-mail, faxes, images, documents, and any other information that a

user desires to store and access with thq data devices 102 and 104.

The directory 112 receives queries from the processor 108, accesses the directory

database 1 14, and uses information received from the processor 108 to cross reference

additional information about users stored in records and the directory database 1 14. Information that the directory 1 12 retrieves from the directory database 1 14 is sent to the

processor 108. Thus, the directory 112 performs functions such as determining the terminal

points where a user can be reached, determining the user's PBX extension, and/or a network

address of a data device. This information is sent to the processor 108 from the directory 1 12

on the basis of queries received from the processor 108.

The directory 1 12 can also perform all or some of the functions performed by the

processor 108. Likewise, the processor 1 12 can perform all or some of the functions

performed by the directory 1 12. Thus, it is not necessary to have both a processor and a

directory. As shown in Figure 1 , the directory 112 can communicate with the packet-

switching network 106 and the ACP system 130 as well as the processor 108. As a result,

processing can be distributed between the processor 108 and the directory 1 12 in any desired

manner.

The directory database 1 14 stores records that associate users' aliases with their PBX

extensions, group ID numbers, network addresses, and the one or more locations

corresponding to each user's PBX extension.

The traditional telephony network 1 16 includes one or more PBXs 118, telephones

120, a PSTN 122, fax machines 124, modems 126, one or more packet network telephony

gateways 128, and one or more ACP systems 130.

The PBX 1 18 is any conventional PBX, and the PSTN 122 is any conventional PSTN.

Conventional PBXs and PSTNs are despribed in Keiser and Strange, "Digital Telephony and

Network Integration," 2^nd ed. and in Stallings, "Data and Computer Communications," 4^th ed.

The telephones 120 are conventional and are connected to, and communicate with, the PBX 1 18 and the PSTN 122. The tax machines 124 and the modems 126 are conventional and are

also connected to the PSTN 122.

The packet network telephony gateway 128 connects the packet-switching network

106 to the PBX 1 18 and the PSTN 122. The packet network telephony gateway 128 receives

information from the packet-switching network 106 and converts the information to a form

compatible with the PBX 1 18 and/or the PSTN 122. The packet network telephony gateway

128 also receives information from the PBX 1 18 and the PSTN 122 and converts such

information into a form compatible with the packet-switching network 106. Thus, the packet

network telephony gateway 128 serves as an interface between the packet-switching network

106 of the virtual PBX system 100 and the conventional telephony system 1 16. The packet

network telephony gateway 128 may be an H.323 gateway PC, such as that described in

http://quicknet.net support/AppNotes/AN00004.htm. The packet network telephony gateway

128 may include a gatekeeper or other device or software for interfacing a packet-switching

network and a conventional telephony system.

The ACP system 130 is any known ACP system for controlling processes such as

collect call and messaging for example. One such ACP system is described in U.S. Pat. No. 5,787,150 to Reiman et al., entitled "Method and System for Automated Collect Call

Messaging," which is incorporated by reference herein. The ACP system 130 automatically

processes calls received via the PSTN 122 and connects calls to the processor 108 and/or the

directory 1 12 of the virtual PBX system) 100.

It is emphasized that the virtual PBX system 100 of Figure 1 is for exemplary

purposes only, as many variations and permutations of the hardware used to implement the

present invention will be readily apparent to one having ordinary skill in the art. To implement these variations, a single computer (e.g., the computer 1000 of Figure 10) may be

programmed to perform the special purpose functions of two or more of any of the devices shown in Figure 1. For example, a single computer could be programmed to function as both

the processor 108 and the directory 112. On the other hand, by using distributed processing

techniques, for example, two more programmed computers, may be substituted for any one of

the devices shown in Figure 1.

The present invention stores information relating to the users of the virtual PBX

system 100. This information includes the users' PBX extensions, aliases, IP 'addresses, and

the locations of different terminal points for each user extension, as well as the order of

preference that the terminal points are to be accessed or dialed. This information is stored in

one or more memories such as a hard disk, optical disk, magneto-optical disk, and/or random

access memory (RAM), for example. One or more databases, such as the storage object

database 1 10 and or the directory database 1 14, may store the information used to implement

the present invention. The databases are organized using data structures (e.g., records, tables,

arrays, fields, and/or lists) contained in a memory such as a hard disk, optical disk, magneto- optical disk, and/or RAM, for example.

Figures 2-4 depict data structures for implementing a virtual PBX system. These data

structures are used by the processor 108 and the directory 1 12 of the virtual PBX system 100

to perform automatic switching, call routing, and other operations similar to those performed

on a conventional PBX. The data structures shown in Figures 2-4 are stored in the object

storage database 1 10, the directory database 1 14, and/or any other suitable storage device.

The information stored in the data structures includes identifiers for uniquely identifying

users and linking users to their PBX extensions, group ID numbers, and terminal points, as

-I T well as for dynamically tracking the network addresses of the data devices of users that are

logged onto the virtual PBX system 100 via the IP address of the data devices.

Figure 2 shows an extension aliases record 200 that includes a field 202 for storing

aliases, a field 204 for storing group ID numbers, and a field 206 for storing users' PBX

extensions. An alias is an identifier that uniquely identifies the user when he or she logs into

the virtual PBX system 100. As shown in Figure 2, the aliases are e-mail addresses.

Alternatively, the aliases are any alphanumeric identifiers such as a telephone numbers, social

security numbers, billing account numbers, etc. The group ID numbers are associated with

respective of the aliases and identify the group corresponding to each alias. The extension

identifies the user's virtual PBX extension, which is analogous to an extension in a

conventional PBX system. The field 204 for storing the group ID numbers does not have to

be used. However, the use of group ID numbers permits users in different groups to have the

same PBX extension numbers.

Figure 3 is an extension locations record 300 that includes a field 302 for storing

group ID numbers, a field 304 for storing user extensions, a field 306 for storing location

orders, and a field 308 for storing terminal point locations. The group ID numbers and the

user extensions are the same as the group identification numbers and the users extensions

stored in the fields 204 and 206, respectively, of the extension aliases record 200. The

location order is the order of preference that the processor 108 will use in attempting to

connect calls to the terminal point locatipns associated with a user. The terminal point

locations are stored in field 308. Thus, referring to the extension locations record 300 shown

in Figure 3 by way of example, if the processor 108 tries to connect a call to a user with the

group ID number 299 and the user extension 1234, the processor 108 will first attempt to reach the user via the packet-switching network 106 because the "packet network" entry

corresponds to the first terminal point location. If attempts to reach the user via the packet- switching network 106 fail, the processor 108 will then try to connect the call to the user via

the number 555-1 1 1-2222, because 555-1 1 1-2222 corresponds to the second terminal point

location for the user. Note that 555-1 1 1-2222 is a conventional telephone number to be used

in the conventional telephone network 1 16 of Figure 1, for example. Other examples of

locations include voice mail directories, the receptionist in the building of the user to be

called, the user's secretary, the user's supervisor, and or a voice mail system. ι

Figure 4 shows a packet network locations record 400 that includes a field 402 for

storing group ID numbers, a field 404 for storing user extensions, and a field 406 for

dynamically storing the network address of the user. The group ID numbers and the user

extensions are the same as those stored in the fields 204 and 206, respectively, of the

extension aliases record 200 shown in Figure 2. The network address is the address

associated with the data devices (e.g., the data devices 102 and 104 in Figure 1) connected to

the packet-switching network on which the virtual PBX system is implemented. In the

examples shown in Figure 4, the network addresses are IP addresses, and thus, the Internet

can be used as the packet-switching network 106. The presence of a network address in the

field 406 corresponding to a particular group ID number in field 402 and a particular user

extension in the field 404 indicate that the user associated with that group ID number and user

extension number are logged onto the victual PBX system (i.e., that user is "online"). The

absence of an address in the field 406¹ indicates that the user associated with the

corresponding group ID number in field 402 and the corresponding user extension in field

404 is not logged into the virtual PBX system 100 (i.e., that user is "offline"). Accordingly, when a user logs in, an entry corresponding to the user's network

address (e.g., the IP address of the user's data device) is created in the packet network

locations record 300 and associated with the user's virtual PBX extension and group ID

number. In this manner, the present invention is able to dynamically track the locations of

users of the virtual PBX system 100 by storing the network address of the data device through

which the user has logged onto the virtual PBX system 100. As an example of the flexibility

and convenience that the virtual PBX 100 of the present invention provides, a user could (1)

participate in a telephone conference using the data device 102, which may be located in the

user's office, (2) disconnect from the conference, and (3) log in using the data device 104,

which may be located in the user's automobile.

It is to be understood that the data structures shown in Figures 2-4 are provided by

way of example, and many variations and permutations of the organization of the information

used by the present invention will be readily apparent to one having ordinary skill in the art.

For example, a separate record may be used to link users' aliases to their group ID numbers.

In that case, separate extension alias records, extension locations records, and packet network

locations records can be created for each group and populated only with information for the

corresponding group. Additionally, if each user has a unique user extension number, then the

group ID numbers can be eliminated entirely.

Figure 5 is a flow chart explaining how a user logs onto the virtual PBX system 100.

In step 502 the user connects to the packiet-switching network 106 using a data device, such

as the data device 102. This connection can be accomplished using known network

protocols. In step 504, the agent 103 running on the data device contacts the directory 1 12 to

supply authentication, register the user's alias, and register the location of the data device. The authentication, alias, and location can be input manually by the user. However, the alias

and authentication are preferably input by the user, and the location (e.g., the IP address of

the data device 102) is sent by the agent 103 to the directory 1 12 via the packet-switching

network 106 automatically. The authentication is preferably a password that the directory

1 12 compares to passwords stored in the directory database 1 14. If there is a match between

the authentication passwords sent by the agent 103 and one of the authentication passwords in

the directory database 1 14, then the user is authenticated (step 506). If there is no match, then

the user is disallowed to the virtual PBX system 100 in step 508.

If the user successfully logs in, the network address (e.g., the IP address) of the data

device that the user has connected to the virtual PBX system is linked to the virtual PBX

extension of the user. As noted above, users are not required to maintain static locations and

can log onto the system on different data devices while maintaining the same user extension.

Figure 6 is a flow chart showing the processing of different options available to a user

logged onto the virtual PBX system 100. The process shown in Figure 6 is preferably

performed by the processor 108, but alternatively, a portion of the processing can be

performed by the directory 1 12. In step 602 the processor 108 checks to determine whether

the user, who is logged into the system, wishes to make an outbound call. If the user wishes

to make an outbound call, then the process proceeds to step 702 shown in Figure 7. Referring

back to Figure 6, if the user does not wish to make an outbound call, the processor determines

whether the user wishes to access his oriher message options in steps 604. If the user wishes

to access his or her message options, then the process proceeds to step 605 and message

options are invoked. These message options include standard message options available on a conventional telephone network, such as voice mail, message forwarding, reminders, or any

other known message options.

If the user does not wish to access message options in step 604, then the process

proceeds to step 606. In step 606, the processor 108 determines whether the user wishes to

access user options. If the user wishes to access user options, then user options are invoked in

step 608. User options include standard user options such as storing a greeting message,

changing the greeting message, setting the number of rings before an incoming caller is

forwarded to voice mail, or any known features or options used in a conventional telephony

system. Additionally, the user may be permitted to change the location order (stored in the

field 306 in Figure 3) associated with his or her user extension in the extension locations

record 300. If the user does not wish to access user options in step 606, then the processor

determines whether the user wishes to disconnect or log off in step 610. If the user wishes to

disconnect, then in step 612, the data device 102 sends a disconnect message to the directory

1 12. Then, in step 614, the directory uses the user's alias, provided at log in, to find the group

ID and extension coπesponding to the user and locate the user's network address in the packet

network locations table 400. Then, the network address is disassociated from the user's group

ID number, virtual PBX extension, and alias. As a result, the user is logged off and is

deemed to be offline.

If the processor determines in step 610 that the user has not disconnected, then steps

602, 604, 606, and 610 are repeated until the processor 108 determines that the user wishes to

make an outbound call, access message options, access user options, or disconnect.

Figures 7 and 8 are flow charts for explaining how an outbound call is made. If a user

wishes to make an outbound call in step 602 (Figure 6), then the agent 103 sends a message to the processor 108 to make an outbound call in step 702. Then, in step 704, the processor

108 queries the directory 1 12 for the destination of the call. In step 706, the directory 1 12

determines whether the destination of the call is an internal user (i.e., a user of the virtual

PBX or a user with an alias). If the destination is not an internal user, then the call is

connected to the PSTN 122 via the packet network telephony gateway 128 in step 708. If the

destination of the call is an internal user, then the directory 112 determines whether the

destination is to a PSTN in step 802 (Figure 8) by accessing the first terminal point location

for the destination user in the extensions locations record 300. The locations stored in the

field 308 (Figure 3) indicate whether the destination user will first be attempted to be

contacted on the packet-switching network 106 or the conventional telephony system

If the destination is to a PSTN, then the process proceeds to step 804. In step 804 the

directory determines whether the destination user is online by determining whether an IP

address is associated with the destination user's virtual PBX extension in the packet network

locations record 400. If an IP address is associated with the destination user's virtual PBX

extension, then the destination user is determined to be online. If the destination user is

online, then in step 806 the directory accesses the packet network locations record 400 to find

the network address of the destination user's data device. The destination network address is

sent to the processor 108, which initiates the call to that network address in step 808. Then,

the processor 108 determines whether the destination user accepts the call in step 810. If the

destination user does not accept the call₎, then the processor 108 notifies the directory 1 12, and

the directory 1 12 determines whether the destination user has more terminal point locations in

the extension locations record 300 in step 812. If the destination user has more locations,

then the directory 1 12 selects the next location, based on the location order in the extension locations table 300, in step 814, and the process returns to step 704. Similarly, if the

destination user is determined to be offline in step 804, then the process proceeds to step 812

to determine whether the user has additional terminal point locations. If the user has no more

terminal point locations, then in step 816, the caller is forwarded to the destination user's

voice mail system on the processor 108. Voice messages are stored in the object storage

database 1 10.

If, in step 802, the directory 1 12 determines that the destination is not to the PSTN

122, then the process proceeds to step 818. In step 818 the processor 108 connects the call to

the PSTN 122 via the packet network telephony gateway 128. Then, in step 820 the

processor 108 determines whether the call was successful. If the call was not successful then

the process proceeds to step 812 to determine whether the destination user has more terminal

point locations in the extension locations record 300.

Figure 9 is a flow chart showing how calls can be made through the PSTN network

122 to the data devices 102 and 104 of the virtual PBX system 100. In step 902, a user dials a

number coπespondir.g to another user at a data device (e.g., the data device 102) of the virtual

PBX system. For example, the user at the telephone 120 dials the number corresponding to

the user at the data device 102. Upon dialing the number in step 902, the telephone 120 is

connected to the PSTN 122, directly or through the PBX 1 18, depending on whether the

telephone 120 is required to access the PSTN 122 through the PBX 1 18. In step 904, the

PSTN 122 determines whether to route \hc call to the ACP system 130 or to the packet

network telephony gateway 128. If the PSTN 122 routes the call to the ACP system 130,

then in step 908, the call is routed directly to the processor 108 or alternatively, to the

directory 1 12. If the PSTN 122 routes the call to the packet network telephone gateway 128, then in step 906, the call is routed to the processor 108 (or alternatively, the directory 112) via

the packet- switching network 106.

As shown in Figures 5-9, call processing and switching within the virtual PBX system

100 is performed by the processor 108 and directory 1 12, and therefore, the intelligence of the

virtual PBX system 100 is advantageously located on the network side, and not in the

terminal devices (i.e., not within the data devices 102 and 104). Moreover, since the call

processing and switching is performed by the processor 108 and the directory 1 12, there is no need for conventional telephony equipment for call routing within the virtual PBX network

100.

Additionally, the interface between the packet network telephony gateway 128 and the

virtual PBX system 100 and the ACP system 130 provides connectivity between the virtual

PBX system of the present invention and existing PSTNs and PBXs.

All or a portion of the invention may be conveniently implemented using

conventional general purpose computers or microprocessors programmed according to the

teachings of the present invention, as will be apparent to those skilled in the computer xt.

Appropriate software can be readily prepared by programmers of ordinary skill based on the

teachings of the present disclosure, as will be apparent to those skilled in the software art.

Figure 10 is a schematic illustration of a computer system 1000 for implementing the

method of the present invention. The computer system 1000 includes a computer housing

1002 for housing a mother board 1004, which contains a CPU 1006, a memory 1008 (e.g.,

RAM, dynamic RAM (DRAM), static RAM (SRAM), synchronous DRAM (SDRAM), flash

RAM, read-only memory (ROM), programmable ROM (PROM), erasable PROM (EPROM),

and electrically erasable PROM (EEPROM)), and other optional special purpose logic devices (e.g., application specific integrated circuits (ASICs)) or configuraole logic devices

(e.g., generic aπay of logic (GAL) or reprogrammable field programmable gate arrays

(FPGAs)). The computer system 1000 also includes plural input devices, such as a keyboard

1022, a mouse 1024, and a microphone 126, and a speaker 128 and display card 1010 for

controlling a monitor 1020. In addition, the computer system 1000 further includes a floppy

disk drive 1014; other removable media devices (e.g., a compact disc 1019, a tape, and a

removable magneto-optical media); and a hard disk 1012, or other fixed, high density media

drives, connected using an appropriate device bus (e.g., a small computer system interface

(SCSI) bus, and enhanced integrated device electronics (IDE) bus, or an ultra-direct memory

access (DMA) bus). The computer system 1000 may additionally include a compact disc

reader 1018, a compact disc reader-writer unit, or a compact disc juke box, each of which

may be connected to the same device bus or another device bus. Although the compact disc

1019 is shown in a CD caddy, the compact disc 1019 can be inserted directly into CD-ROM

drives which do not require caddies. In addition, a printer may provide printed listings of the

data structures shown in Figures 2-4 or any other data stored and/or generated by the

computer system 1000.

As stated above, the system includes at least one computer readable medium or

memory programmed according to the teachings of the invention and for containing data

structures, tables, records, or other data described herein. Examples of computer readable

media are compact discs, hard disks, floppy disks, tape, magneto-optical disks, PROMs

(EPROM, EEPROM, Flash EPROM , DRAM, SRAM, SDRAM, etc. Stored on any one or

on a combination of computer readable media, the present invention includes software for

controlling both the hardware of the computer 1000 and for enabling the computer 1000 to interact with a human user (e.g., a consumer). Such software may include, but is not limited

to, device drivers, operating systems and user applications, such as development tools. Such

computer readable media further includes the computer program product of the present

invention for performing all or a portion (if processing is distributed) of the processing

performed in implementing the invention. The computer code devices of the present

invention can be any interpreted or executable code mechanism, including but not limited to

scripts, interpreters, dynamic link libraries, Java classes, and complete executable programs.

Moreover, parts of the processing of the present invention may be distributed for better

performance, reliability, and/or cost.

The invention may also be implemented by the preparation of application specific

integrated circuits or by interconnecting an appropriate network of conventional component

circuits, as will be readily apparent to those skilled in the art.

Obviously, numerous modifications and variations of the present invention are

possible in light of the above teachings. It is therefore to be understood that within the scope

of the appended claims, the invention may be practiced otherwise than a:; specifically

described herein.

Claims

1. A method of routing calls within a packet-switching network, comprising the steps

of:

receiving from a data device login information including an alias identifying a user at

the data device and a network address identifying the location of the data device on the

packet-switching network;

associating a private branch exchange extension of the user with the network address;

receiving a call to the user's private branch exchange extension; and

routing the received call to the data device on the basis of the network address of the

data device.

2. A method according to claim 1 , further comprising the steps of:

associating an alias identifying the user with the user's private branch exchange

extension.

3. A method according to claim 2, wherein the step of associating the user's private

branch exchange extension with the network address comprises the step of:

linking the user's private branch exchange extension to the network address of the data

device in response to receiving the user's alias.

4. A method according to claim 1 , further comprising the step of:

receiving from the data device a disconnect command indicating that the user desires

to log off of the packet-switching netwofk.

5. A method according to claim 4, further comprising the step of:

disassociating the network address from the user's private branch exchange extension

in response to receiving the disconnect command.

6. A method according to claim 5, further comprising the step of:

receiving from another data device other login information including the alias identifying the user at the other device and another network address identifying the location

of the other data device on the packet-switching network; associating a private branch exchange extension of the user with the other network

address;

receiving another call to the user's private branch exchange extension; and

routing the other call to the other data device on the basis of the other network address

of the other data device.

7. A method according to claim 2, further comprising the step of:

receiving the user's alias from different data devices connected to the packet-switching

network at different times;

tracking locations of the user on the packet-switching network on the basis of the

respective network addresses of the different data devices; and

routing calls to the one of the different data devices from which the user's alias was last received.

8. A virtual private branch exchange system implemented on a packet-switching

network, comprising:

means for receiving from a data device login information including an alias

device on the packet-switching network;

means for associating a private branch exchange extension of the user with the

network address; means for receiving a can ιθ the user's private branch exchange extension; and

means for routing the received call to the data device on the basis of the network

address of the data device.

9. A virtual private branch exchange system according to claim 8, further comprising:

means for associating an alias identifying the user with the user's private branch

exchange extension.

10. A virtual private branch exchange system according to claim 9, wherein the

means for associating the user's private branch exchange extension with the network address,

comprises:

means for linking the user's private branch exchange extension to the network address

of the data device in response to receiving the user's alias.

1 1. A virtual private branch exchange system according to claim 8, further comprising:

means for receiving from the data device a disconnect command indicating that the

user desires to logoff of the packet-switching network.

12. A virtual private branch exchange system according to claim 11, further

comprising:

means for disassociating the network address from the user's private branch exchange

extension in response to receiving the disconnect command.

13. A virtual private branch exchange system according to claim 12, further

comprising: means for receiving from another data device other login information including the

alias identifying the user at the other device and another network address identifying the

location of the other data device on the packet- switching network;

means for associating a private branch exchange extension of the user with the other

network address; means for receiving another call to the user's private branch exchange extension; and

means for routing the other call to the other data device on the basis of the other

network address of the other data device.

14. A virtual private branch exchange system according to claim 9, further

comprising:

means for receiving the user's alias from different data devices connected to the

packet-switching network at different times;

means for tracking locations of the user on the packet-switching network on the basis

of the respective network addresses of the different data devices; and

means for routing calls to the one of the different data devices from which the user's alias was last received.

15. A virtual private branch exchange system implemented on a packet-switching

network, comprising:

a memory configured to store information associating a user with a private branch

exchange extension of the user;

a directory unit configured to receive from a data device login information including

an alias identifying the user at the data device and a network address identifying the location

of the data device on the packet-switching network, configured to access the memory to associate a private branch exchange extension of the user with the network address,

configured to process information of a received call, the information including the user's

private branch exchange extension, and configured to route the received call to the data

device on the basis of the network address of the data device.

16. A virtual private branch exchange system according to claim 15, wherein the

memory is further configured to store information associating an alias identifying the user

with the user's private branch exchange extension.

17. A virtual private branch exchange system according to claim 16, wherein the

directory unit is further configured to link the user's private branch exchange extension to the

network address of the data device in response to receiving the user's alias.

18. A virtual private branch exchange according to claim 16, wherein the directory

unit is further configured to receive the user's alias from different data devices connected to

the packet-switching network, configured to track locations of the user on the packet-

switching network on the basis of the respective network addresses of the different data

devices, configured to process oiher information of another received call, the other

information including the user's private branch exchange extension, and configured to route

the other received call to the one of the different data devices from which the user's alias was last received.

19. A computer readable medium storing program instructions for execution on a

computer system, which when executed by a computer, cause the computer to perform the

steps of: receiving from a data device login information including an alias identifying a user at the data device and a network address identifying the location of the data device on the

packet-switching network;

receiving a call to the user's private branch exchange extension; and

data device.

20. A computer readable medium according to claim 19, further comprising program

instructions for causing the computer to perform the steps of:

extension.

21. A method according to claim 20, wherein the step of associating the user's private

branch exchange extension with the network address, comprises the step of:

device in response to receiving the user's alias.

22. A computer readable medium according to claim 19, further comprising program

instructions for causing the computer to perform the steps of:

to logoff of the packet-switching network.

23. A computer readable medium according to claim 19, further comprising program

instructions for causing the computer to perform the steps of:

in response to receiving the disconnect command.

24. A computer readable medium according to claim 23, further comprising program

instructions for causing the computer to perform the steps of:

receiving from another data device other login information including the alias

identifying the user at the other device and another network address identifying the location

of the other data device on the packet-switching network;

associating a private branch exchange extension of the user with the other network

address;

receiving another call to the user's private branch exchange extension; and

of the other data device.

25. A computer readable medium according to claim 20, further comprising program

instructions for causing the computer to perform the steps of:

network at different times;

tracking 1-.. cations of the user on the packet-switching network on the basis of the •

respective network addresses of the different data devices; and

routing calls to the one of the different data devices from which the user's alias was

last received.

26. A memory for storing information for implementing a virtual private branch

exchange on a packet-switching network), comprising a data structure including:

a field for storing private branch exchange extensions of users registered with the

virtual private branch exchange; and a field for dynamically storing network addresses identifying the respective locations

of data devices connected to the packet-switching network, the network addresses being

dynamically associated with corresponding of the users' private branch exchange extensions.

27. A memory according to claim 26, further comprising another data structure

including:

a field for storing aliases identifying respective of the users, the aliases being linked to

coπesponding of the users' private branch exchange extensions.