Methods and systems for message forwarding and property
notifications using electronic subscriptions
Abstract
A messaging system is described in which subscription requests are
transmitted over the Internet using Internet protocols such as extensions of
HyperText Transport Protocol (HTTP). The subscription request may be for a wide
variety of information from the remote device. For example, the subscription
request might be for messages to be forwarded from the device as they are
received. Also, the subscriptions could be for messages to be generated when a
property value of the remote device has a predetermined characteristic. Such
property values might include, for example, stock prices, inventory levels,
online status, error codes, heart rates, and the like. The subscription request
itself is a data structure representing a subscribe method identification, an
address of the device containing the information, and an address of the device
to which the information is to be forwarded. Optionally, the subscription
request may also define the conditions under which a message is to be forwarded,
or under which a property notification is to be sent.
Inventors:
Aggarwal; Sudhanshu M. (Bellevue, WA);
Beebee; Peter L. (Redmond, WA); Surati; Rajeev (Seattle,
WA); Wong; Leon C. W. (Redmond, WA); Calsyn; Martin R.
(Carnation, WA)
DellaFerra et al., "The Zephyr Notification Service,"
Usenet Conference, Feb. 1988. Lamacchia, David, "The Flame
Client-Based Instantaneous Datagram Communication Substrate" SB Thesis,
Massachusetts Institute of Technology, May 1996.
Primary Examiner: Trammell; James P.
Assistant Examiner: Elisca; Pierre Eddy Attorney, Agent or
Firm: Workman, Nydegger & Seeley
Parent Case Text
RELATED APPLICATION
This application is a continuation-in-part
of U.S. application Ser. No. 09/286,257 entitled "Inter-Enterprise Messaging
System Using Bridgehead Servers", filed Apr. 5, 1999, which is incorporated
herein by reference. That application is a continuation-in-part of U.S.
application Ser. No. 08/832,758, entitled "System for Immediate Popup Messaging
Across the Internet," filed Apr. 4, 1997, now U.S. Pat. No. 5,943,478 which is
incorporated herein by reference.
Claims
What is claimed and desired to be secured by United States Letters
Patent is:
1. In a first device that is included in a network system
that also includes a second device, the first device being capable of monitoring
the value of a property at the first device, a method of transmitting a message
from the first device to the second device when the value of the property at the
first device experiences a specified conditions so that the second device is
notified that the value of the property has experienced the specified condition,
the method comprising the acts of:
receiving a subscription request from
the second device, the subscription request specifying:
the property to
which the second device is subscribing; and
a condition associated with
the value of the property, wherein the subscription request represents a request
for the first device to generate a message when the value of the specified
property at the first device experiences the specified condition;
in
response to receiving the subscription request, monitoring the value of the
specified property at the first device, resulting in the first device making a
determination that the value of the specified property has experienced the
specified condition;
upon the first device making the determination,
generating a message that includes information identifying the value of the
specified property at the first device; and
transmitting the message
from the first device to the second device, such that the second device is
notified that the value of the property has experienced the specified condition.
2. The method of claim 1, wherein the act of receiving the subscription
request from the second device comprises the following act of:
receiving
the subscription request over the Internet from the second device using an
extension of HyperText Transport Protocol (HTTP).
3. The method of claim
1, wherein the act of monitoring the value of the specified property comprises
act of:
monitoring the value of the specified property for a
predetermined time period and upon the completion of the time period ceasing
monitoring the value of the specified property.
4. The method of claim
1, wherein the message is a first message, the method further comprising the
following act of:
generating a message forwarding subscription request
to be sent to the second device from a third device so as to result in, when the
messaging forwarding subscription request is received at the second device, a
second message being sent from the second device to a third device when the
second device receives the first message.
5. The method of claim 1,
wherein the act of monitoring the value of the specified property comprises
monitoring when an online status value of the property at the first device
changes.
6. The method of claim 1, wherein the value of the property
comprises
a value selected from the group consisting of a stock price
value, a heart rate value, and an inventory value.
7. The method of
claim 1, wherein the subscription request is a first subscription request,
wherein the message is a first message, the method further comprising the
following act:
generating a second subscription request so as to result
in, when the second subscription request is received at the second device, a
second electronic message being sent from the second device to a third device
when the second device receives the first electronic message.
8. The
method of claim 1, wherein the subscription request is a first subscription
request, wherein the message is a first electronic message, the method further
comprising the following step:
generating a second subscription request
so as to result in, when the second subscription request is received at the
second device, a second electronic message having the same content as the first
electronic message being sent from the second device to a third device when the
second device receives the first electronic message.
9. The method of
claim 1, wherein the subscription request is a first subscription request,
wherein the message is a first electronic message, the method further comprising
the following step:
generating a second subscription request so as to
result in, when the second subscription request is received at the first device,
a second electronic message having the same content as the first electronic
message being sent from the first device to at least one other device upon the
happening of the specified condition.
10. In a first device that is
included in a network system that also includes a second device, the first
device being capable of monitoring receipt of an electronic mail message at the
first device, a method of transmitting the electronic mail message from the
first device to the second device when the electronic mail message is received
by the first device so that the electronic mail message is automatically
forwarded to the second device, the method comprising the acts of:
receiving a subscription request from the second device, the
subscription request specifying:
the first device to which the second
device is subscribing; and
a condition associated with the electronic
mail message, wherein the subscription request represents a request for the
first device to forward the electronic mail message from the first device upon
the first device experiencing the specified condition;
in response to
receiving the subscription request, monitoring the receipt of the electronic
mail message at the first device, resulting in the first device making a
determination that the first device has experienced the specified condition;
upon the first device making the determination, transmitting the
electronic mail message from the first device to the second device, such that
the second device is notified that the first device has experienced the
specified condition.
11.The method of claim 10, wherein the act of
receiving the subscription request from the second device comprises the act of
receiving the subscription request over the Internet from the second device
using an extension of HyperText Transport Protocol (HTTP).
12. The
method of claim 10, wherein the act of receiving the subscription request from
the second device comprises the act of receiving the subscription request over
the Internet from the second device using an HyperText Transport Protocol
(HTTP).
13. The method of claim 10, wherein the specified condition
comprises receiving the electronic mail message at the first device.
14.
The method of claim 10, wherein the subscription request is a message forwarding
subscription request so as to result in, when the first device receives the
message forwarding subscription request, the electronic mail message that was
originally addressed to the first device being forwarded from the first device
to the second device as the first device receives the electronic mail message.
15. The method of claim 10, wherein the act of monitoring the receipt of
the electronic mail message comprises the act of monitoring the receipt of the
electronic mail message for a predetermined time period and upon the completion
of the time period ceasing monitoring the receipt of the electronic mail
message.
16. The method of claim 15, wherein upon completion of the time
period, ceasing to forward the electronic mail message received at the first
device to the second device.
17. The method of claim 15, wherein the
subscription request comprises a subscription lifetime defining the time period
that the first device monitors receiving the electronic mail message.
18. The method of claim 10, wherein the electronic mail message is a
first electronic mail message, the method further comprising the act of:
generating a message forwarding subscription request so as to result in,
when the message forwarding subscription request is received by the second
device, a second electronic mail message being send from the second device to at
least one other device when the second device receives the first electronic mail
message.
19. The method of claim 18, wherein the second electronic mail
message is the same as the first electronic mail message.
20. A computer
product for implementing, in a system that includes a first device and a second
device, the first device being capable of monitoring the value of a property at
the first device, a method of transmitting a message from the first device to
the second device when the value of the property at the first device experiences
a specified conditions so that the second device is notified that the value of
the property has experienced the specified condition, the computer program
product comprising:
a computer readable medium carrying
computer-executable instructions for implementing the method, wherein the
computer-executable instructions, when executed by the system, cause the system
to perform the acts of:
receiving a subscription request from the second
device, the subscription request specifying:
the property to which the
second device is subscribing; and
a condition associated with the value
of the property, wherein the subscription request represents a request for the
first device to generate a message when the value of the specified property at
the first device experiences the specified condition;
in response to
receiving the subscription request, monitoring the value of the specified
property at the first device, resulting in the first device making a
determination that the value of the specified property has experienced the
specified condition;
upon the first device making the determination,
generating a message that includes information identifying the value of the
specified property at the first device; and
transmitting the message
from the first device to the second device, such that the second device is
notified that the value of the property has experienced the specified condition.
21. The computer product of claim 20, wherein the act of receiving the
subscription request from the second device comprises the following act of:
receiving the subscription request over the Internet from the second
device using an extension of HyperText Transport Protocol (HTTP).
22.
The computer product of claim 21, wherein the act of monitoring the value of the
specified property comprises the act of:
monitoring the value of the
specified property for a predetermined time period and upon the completion of
the time period ceasing monitoring the value of the specified property.
23. The computer product of claim 21, wherein the message is a first
message, the method further comprising the following act of:
generating
a message forwarding subscription request to be sent to the second device from a
third device so as to result in, when the messaging forwarding subscription
request is received at the second device, a second message being sent from the
second device to a third device when the second device receives the first
message.
24. The computer product of claim 21, wherein the act of
monitoring the value of the specified property comprises monitoring when an
online status value of the property at the first device changes.
25. The
computer product of claim 21, wherein the value of the property comprises a
value selected from the group consisting of a stock price value, a heart rate
value, and an inventory value.
26.The computer product of claim 21,
wherein the subscription request is a first subscription request, wherein the
message is a first message, the method further comprising the following act:
generating a second subscription request so as to result in, when the
second subscription request is received at the second device, a second
electronic message being sent from the second device to a third device when the
second device receives the first electronic message.
27. The computer
product of claim 21, wherein the subscription request is a first subscription
request, wherein the message is a first electronic message, the method further
comprising the following step:
generating a second subscription request
so as to result in, when the second subscription request is received at the
second device, a second electronic message having the same content as the first
electronic message being sent from the second device to a third device when the
second device receives the first electronic message.
28. The computer
product of claim 21, wherein the subscription request is a first subscription
request, wherein the message is a first electronic message, the method further
comprising the following step:
generating a second subscription request
so as to result in, when the second subscription request is received at the
first device, a second electronic message having the same content as the first
electronic message being sent from the first device to at least one other device
upon the happening of the specified condition.
Description
BACKGROUND OF THE INVENTION
1. The Field of the Invention
The present invention relates to electronic communications.
Specifically, the present invention relates to methods and systems for message
forwarding and property notification using electronic subscriptions.
2.
The Prior State of the Art
Electronic communication technology has
advanced significantly in modern times. Currently, information is commonly
exchanged over computer networks. The largest and most far reaching of all
computer networks has been termed "the Internet" which links devices worldwide.
The Internet is essentially composed of a worldwide network of interlinked
computer servers. Other smaller networks ("intranets") used to link local
devices in, for example, a company or organizational environment are termed
local area networks (LANs). LANs may also be interconnected to each other over
the Internet.
Communication over the Internet can occur in several ways.
A sender may send an unsolicited message to the recipient via, for example,
e-mail. While such unsolicited e-mail often contains desired information, the
e-mail might also contain information that is not desired or not timely. Thus,
recipients often generate a request focussed on desired information. For
example, a user may use an Internet browser and type in a uniform resource
locator (URL) address corresponding to a piece of desired information such as,
for example, a stock price residing on a remote server. The user then submits
the request over the Internet using a protocol such as HyperText Transport
Protocol (HTTP). Upon receiving the request, the remote server transmits the
data back to the user's Internet browser.
While the requested
information may be desired, the information may still not be timely. After all,
the user only periodically checks for the desired information since a request
must be generated to check for the desired information. If the user checks for
the desired information once every hour, for example, the information may be as
much as one hour old before the user again requests updated data. That kind of
old data may be useless in many applications. Thus, what was desired is a way of
obtaining real-time information over the Internet from remote devices.
One way for a user to obtain information over the Internet from a remote
device is to subscribe to information on a device containing Internet
broadcasting capability. For instance, a remote server may broadcast information
such as stock prices, files and video to a wide number of users over the
Internet. One disadvantage of such a system is that the remote system must have
expensive and complicated broadcasting capability. There are only a limited
number of such systems available. Often, it is desirable to obtain information
from a device or server that does not have powerful broadcasting capability.
Buddy lists allow for a user to obtain information, albeit limited to
online status, in relative real-time from a remote device. Buddy lists are known
in the context of instant messaging systems. Instant messaging requires the
tracking of the online status of each user in a buddy list since instant
messaging in real-time requires that each correspondent be online. If a
correspondent is listed as off-line, users who have the correspondent listed in
their buddy list will then know not to waste time trying to engage in a
real-time conversation with the off-line correspondent. On the other hand, if
the correspondent is online, users who have the correspondent listed in their
buddy list will know that they can engage in real-time conversation with the
correspondent (assuming the correspondent is willing).
Instant messaging
systems do not give any other information about the remote device other that
online status. After all, online status is the only information about remote
devices that is needed in instant messaging. It is also relatively simple to
determine the online status. The buddy lists ping each other at short intervals
to see who's online. If the ping is successful, the client reports that your
buddy is online and ready to chat. These methods are specifically tailored to
determining online status.
In addition to the disadvantage of only
providing online status, many instant messaging systems have difficulty
communicating through firewalls depending on the firewall characteristics.
Firewalls are machines commonly used for enforcing corporate network security
policies; most business users connect to the Internet through a firewall.
Firewalls represent a significant impediment to real-time communication between
Internet users. Firewall designs generally prohibit external entities on the
Internet from directly connecting to internal entities protected by the
firewall. While such security mechanisms prevent external entities from
maliciously manipulating internal entities, they have had the side effect of
preventing asynchronous communication to an internal entity.
In light of
the above shortfalls, what is desired is a method and system for determining a
wide variety of information about a remote device in real-time even if the
remote device does not have complicated broadcasting capability, and even if the
remote device is on the other side of a firewall.
SUMMARY AND OBJECTS OF
THE INVENTION
The present invention relates to messaging systems in
which information may be subscribed from one device to another. The subscription
requests are transmitted over the Internet using Internet protocols such as
extensions of HyperText Transport Protocol (HTTP). The subscription request may
be for a wide variety of information from the remote device.
For
example, the subscription request might be for messages to be forwarded from the
device as they are received. Thus, a user on vacation may have messages
forwarded from the user's normal messaging server to the client local to the
user. Such a message forwarding subscription request may be generated by and
transmitted from the local client or by any other device capable of generating
and transmitted the request.
Also, the subscriptions could be for
messages to be generated when a property value of the remote device has a
predetermined characteristic. The kinds of property values to which a user can
subscribe is limited only by the values that the device can measure. For
example, stock prices, inventory levels, online status, error codes, heart
rates, light levels, typing speed, number of recently visited Internet sites,
and any other quantity that may be measured may be subscribed to. A user may
subscribe to changes in a stock price residing on a remote server. Furthermore,
a user may subscribe to an online status of a remote client to prepare to
instant message with that client. A user may also subscribe to error codes on
peripheral devices to monitor the peripherals. A doctor may subscribe to a heart
rate of a patient in a remote location measured by a remote device. The number
of applications of this invention is enormous.
The subscription request
itself is a data structure representing a subscribe method identification, an
address of the device containing the information, and an address of the device
to which the information is to be forwarded. Optionally, the subscription
request may also define the conditions under which a message is to be forwarded,
or under which a property notification is to be sent. The device that forwards
the information need not have complex broadcasting capability. The only things
required of the forwarding device is that the device recognizes the subscription
request, recognizes the information requested in the subscription request,
recognizes the address of the call back device indicated in the request, and
forwards the information to the call back device.
Since the subscribe
requests can be generated over the Internet to remote devices with minimal
preparation of the remote device, there is great flexibility is routing
information. For example, newsgroups may be established by a user submitting a
message forwarding subscription request to a server for the server to forward
messages it receives in a given newsgroup directory to a number of clients.
Thus, messages are instantly forwarded to the clients as soon as the message is
posted in the newsgroup directory of the server.
The present invention
also allows for instant forwarding of the messages and property notification
even through firewalls using bridgehead servers as described herein. Messages,
whether they be the original subscription request or the message sent in
response to such a request, may be addressed to the bridgehead server guarding
the network. The message also may include a recipient identifier. Based on this
recipient identifier, the message is transmitted from the bridgehead server to
the appropriate messaging server within the network.
Additional objects
and advantages of the invention will be set forth in the description which
follows, and in part will be obvious from the description, or may be learned by
the practice of the invention. The objects and advantages of the invention may
be realized and obtained by means of the instruments and combinations
particularly pointed out in the appended claims. These and other objects and
features of the present invention will become more fully apparent from the
following description and appended claims, or may be learned by the practice of
the invention as set forth hereinafter.
BRIEF DESCRIPTION OF THE
DRAWINGS
In order that the manner in which the above-recited and other
advantages and objects of the invention are obtained, a more particular
description of the invention briefly described above will be rendered by
reference to specific embodiments thereof which are illustrated in the appended
drawings. Understanding that these drawings depict only typical embodiments of
the invention and are not therefore to be considered limiting of its scope, the
invention will be described and explained with additional specificity and detail
through the use of the accompanying drawings in which:
FIG. 1
illustrates an exemplary system that provides a suitable operating environment
for the present invention;
FIG. 2 is a schematic diagram illustrating a
suitable network environment, including networks operated by different
organizations, in which the invention can be implemented;
FIG. 3 is a
schematic diagram illustrating the route by which a message is transmitted from
a sending client to a recipient client in the network environment of FIG. 2
according to one embodiment;
FIG. 4 is a schematic diagram showing a
bridgehead server as it resolves the address of a messaging server associated
with the recipient client;
FIG. 5 is a diagram of a subscription request
structure in accordance with the invention;
FIG. 6 is a schematic
diagram showing the bridgehead server as it responds to the subscription request
of FIG. 5.
FIG. 7 is a schematic diagram of a newsgroup network being
set up by a subscription request;
FIG. 8 is a schematic diagram
depicting one embodiment of a system for maintaining contact lists showing the
online status and other property values of clients in the networked environment;
and
FIG. 9 is a schematic diagram of a network in which a property
notification is uniquely routed in response to a series of subscription
requests.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The
present invention relates to methods and systems for subscribing to information
from a remote device to have the designated information instantly forwarded to a
call back device specified by the subscriber. For instance, while a user is
traveling, a user may subscribe to her e-mail messages received at the corporate
server associate with her regular office computer. When any change in e-mail
status occurs, namely a new message, the new message is instantly forwarded to
her hand-held text display or the like. Furthermore, a user may desire to be
instantly notified of other property changes in a remote device. For example, a
systems administrator may subscribe to an error status for each printer, copier,
and scanner within the system. When an error message occurs at any device, the
systems administrator is notified at his desk-top computer and thus can take
quick action without waiting to be notified by a user. Another user may desired
to subscribe to a stock price listed on a remote device. Yet another user may
desire to subscribe to an online status to instant message with the remote
device. The present invention even works through firewalls.
The
invention is described below by using diagrams to illustrate either the
structure or processing of embodiments used to implement the systems and methods
of the present invention. Using the diagrams in this manner to present the
invention should not be construed as limiting of its scope. The embodiments of
the present invention may comprise a computer network adapted to perform the
functions disclosed herein or a special purpose or general purpose computer
including various computer hardware, as discussed in greater detail below.
Embodiments within the scope of the present invention also include
computer-readable media having computer-executable instructions or data
structures stored thereon. Such computer-readable media can be any available
media which can be accessed by a general purpose or special purpose computer. By
way of example, and not limitation, such computer-readable media can comprise
RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or
other magnetic storage devices, or any other medium which can be used to store
the desired computer-executable instructions or data structures and which can be
accessed by a general purpose or special purpose computer. When information is
transferred or provided over a network or another communications connection to a
computer, the computer properly views the connection as a computer-readable
medium. Thus, such a connection is also properly termed a computer-readable
medium. Combinations of the above should also be included within the scope of
computer-readable media. Computer-executable instructions comprise, for example,
instructions and data which cause a general purpose computer, special purpose
computer, or special purpose processing device to perform a certain function or
group of functions.
FIG. 1 and the following discussion are intended to
provide a brief. general description of a suitable computing environment in
which the invention may be implemented. Although not required, the invention
will be described in the general context of computer-executable instructions.,
such as program modules, being executed by computers in network environments.
Generally, program modules include routines, programs, objects, components, data
structures, etc. that perform particular tasks or implement particular abstract
data types. Computer-executable instructions associated data structures, and
program modules represent examples of the program code means for executing steps
and acts of the methods disclosed herein.
Those skilled in the art will
appreciate that the invention may be practiced in network computing environments
with many types of computer system configurations, including personal computers,
hand-held devices, multi-processor systems, microprocessor-based or programmable
consumer electronics, network PCs, minicomputers, mainframe computers, and the
like. The invention may also be practiced in distributed computing environments
where tasks are performed by local and remote processing devices that are linked
through a communications network. In a distributed computing environment,
program modules may be located in both local and remote memory storage devices.
With reference to FIG. 1, an exemplary system for implementing the
invention includes a general purpose computing device in the form of a
conventional computer 20, including a processing unit 21, a system memory 22,
and a system bus 23 that couples various system components including the system
memory 22 to the processing unit 21. The system bus 23 may be any of several
types of bus structures including a memory bus or memory controller, a
peripheral bus, and a local bus using any of a variety of bus architectures. The
system memory includes read only memory (ROM) 24 and random access memory (RAM)
25. A basic input/output system (BIOS) 26, containing the basic routines that
help transfer information between elements within the computer 20, such as
during start-up, may be stored in ROM 24.
The computer 20 may also
include a magnetic hard disk drive 27 for reading from and writing to a magnetic
hard disk, not shown, a magnetic disk drive 28 for reading from or writing to a
removable magnetic disk 29, and an optical disk drive 30 for reading from or
writing to removable optical disk 31 such as a CD-ROM or other optical media.
The magnetic hard disk drive 27, magnetic disk drive 28, and optical disk drive
30 are connected to the system bus 23 by a hard disk drive interface 32, a
magnetic disk drive-interface 33, and an optical drive interface 34,
respectively. The drives and their associated computer-readable media provide
nonvolatile storage of computer-executable instructions, data structures,
program modules and other data for the computer 20. Although the exemplary
environment described herein employs a magnetic hard disk, a removable magnetic
disk 29 and a removable optical disk 31, other types of computer readable media
for storing data can be used, including magnetic cassettes, flash memory cards,
digital video disks, Bernoulli cartridges, RAMs, ROMs, and the like.
A
number of program modules may be stored on the hard disk, magnetic disk 29,
optical disk 31, ROM 24 or RAM 25, including an operating system 35, one or more
application programs 36, other program modules 37, and program data 38. A user
may enter commands and information into the computer 20 through keyboard 40,
pointing device 42, or other input devices (not shown), such as a microphone,
joy stick, game pad, satellite dish, scanner, or the like. These and other input
devices are often connected to the processing unit 21 through a serial port
interface 46 coupled to system bus 23. Alternatively, the input devices may be
connected by other interfaces, such as a parallel port, a game port or a
universal serial bus (USB). A monitor 47 or another display device is also
connected to system bus 23 via an interface, such as video adapter 48. In
addition to the monitor, personal computers typically include other peripheral
output devices (not shown), such as speakers and printers.
The computer
20 may operate in a networked environment using logical connections to one or
more remote computers, such as a remote computer 49. Remote computer 49 may be
another personal computer, a server, a router, a network PC, a peer device or
other common network node, and typically includes many or all of the elements
described above relative to the computer 20, although only a memory storage
device 50 has been illustrated in FIG. 1. The logical connections depicted in
FIG. 1 include a local area network (LAN) 51 and a wide area network (WAN) 52
that are presented here by way of example and not limitation. Such networking
environments are commonplace in office-wide or enterprise-wide computer
networks, intranets and the Internet.
When used in a LAN networking
environment, the computer 20 is connected to the local network 51 through a
network interface or adapter 53. When used in a WAN networking environment, the
computer 20 typically includes a modem 54 or other means for establishing
communications over the wide area network 52, such as the Internet. The modem
54, which may be internal or external, is connected to the system bus 23 via the
serial port interface 46. In a networked environment, program modules depicted
relative to the computer 20, or portions thereof, may be stored in the remote
memory storage device. It will be appreciated that the network connections shown
are exemplary and other means of establishing a communications link between the
computers may be used.
Message Transmission
FIG. 2 illustrates
an exemplary network environment or messaging system in which the invention can
be implemented. The general features of the network environment are described.
Then, methods and systems for subscribing to information on remote devices are
described.
In FIG. 2, organization A administers a network 60A, while
organization B administers a network 60B. Networks 60A and 60B each have access
to the Internet 80 or another communication network capable of transmitting
messages between networks. While only two organizations and their associated
networks are illustrated in FIG. 2, the invention is scalable to any number of
networks, organizations, or clients.
Network 60A is protected by
firewall 62A, while network 60B is protected by firewall 62B. As used herein,
the term "firewall" is to be broadly defined. Firewalls are defined to include
any network node that controls or restricts the ability of an entity outside the
node to communicate with network components inside the node. Firewalls also
often restrict the ability of network components inside the firewall from
communicating with outside entities. In the network environment of FIG. 2,
components residing in network 60A are inside firewall 62A, while other
components of FIG. 2 are outside the firewall. Firewalls can be implemented in
routers or in general purpose or special purpose computing devices in ways that
are understood by those skilled in the art. While FIG. 2 illustrates firewalls
62 being implemented at networks 60A and 60B, the principles disclosed herein
can optionally be practiced in the absence of firewalls. For instance,
organization B might be an Internet service provider that is not protected by a
firewall. In this case, the bridgehead servers in organization B might redirect
connecting clients to the appropriate messaging servers instead of forwarding
incoming requests.
The line segments connecting various network
components in FIG. 2 represent the hierarchical relationships between
components, and do not necessarily denote communication paths. Each network 60
includes one or more clients 64 that operate client software for generating,
storing and displaying messages and for performing any other desired functions
in relation to the messages. Clients 64 can constitute any desired computing or
communication device that is capable of generating, storing, or displaying
messages. Moreover, the term "clients" extends to any computing or communication
device, whether associated with a human user, fully automated, or some
combination of human-assisted and automated. In one embodiment in accordance
with the present invention, the client automatically generates a message upon
the happening of a predetermined event. For example, the client may
automatically generate a message including a stock price or other value
monitored by the client whenever the value has a predetermined characteristic.
The client might also be a vending machine that monitors soda can inventory
levels, the vending machine generating a message whenever the soda can inventory
drops below a certain level.
Each client 64 is assigned to one of any
number of messaging servers 66 that reside in network 60. Messaging servers 66
can be substantially any network server that is capable of distributing messages
to clients 64. As shown in FIG. 2, each network 60 can have multiple messaging
servers 66, with each messaging server being associated with multiple clients
64. It is also possible to have a client that registers directly to the
bridgehead server, foregoing an intermediate messaging server. In this
alternative embodiment, the client performs any necessary functions that would
otherwise be performed by its messaging server.
In one embodiment,
messaging servers 66 monitor the current online status of the 13associated
clients 64, manage all communication to and from the clients, and store messages
14 that are intended for the clients but cannot be immediately delivered (e.g.,
if a recipient client is not online when a message is sent). Each client of
messaging server 66 can have a contact list and a subscriber list. The contact
list includes all other users that a particular client has designated as
"correspondents" that the client wishes to regularly keep in touch with. The
subscriber list includes all other clients that have designated the particular
client as a correspondent. Contact lists, subscriber lists, and related
functions of messaging servers will be described in greater detail herein in
reference to FIG. 5.
Each network 60 further includes one or more
bridgehead servers 68. The bridgehead servers can also be substantially any
network server that is adapted to perform the functions that will be described
in greater detail in reference to FIG. 4. Bridgehead servers 68 are exposed
through the corresponding firewall 62 in the sense that entities outside the
network and outside the firewall can address a message to the bridgehead server
and cause the message to be received thereby. Each bridgehead server is
associated with a pool of one or more of the messaging servers 66. Moreover, any
given messaging server 66 might receive messages from only a single bridgehead
server or from multiple bridgehead servers, depending on which pool of messaging
servers it is included in and the composition of the associated pool of
bridgehead servers. In many cases, all bridgehead servers in an organization are
capable of passing messages to all messaging servers.
Selected network
components of FIG. 2 are designated as client A, messaging server A, bridgehead
server A, bridgehead server B, message server B, and client B. These
designations are used in FIG. 3 to describe one example of the path of a message
as it is transmitted from a sending client to a recipient client. FIG. 3
represents the network environment of FIG. 2, and shows only the network
components that are useful in describing the path of the message according to a
specific example.
In this example, client A (64A) generates an
event-driven message 100, which may be an instant or real-time message, to
client B (64B) at organization B This message may be generated by a user
entering a message, or the message may be automatically generated by a program
such as an on-line status notification program. For purposes of message 100,
client A is a sending client, while client B is a recipient client. Any given
client can alternately be a sending client as it transmits a message and a
recipient client as it receives a message.
As shown in FIG. 3, client B
is assigned to messaging server B (66B), and receives messages and, possibly,
other network services from messaging server B. Because messaging server B and
other messaging servers 66 can provide general network services to their
clients, these messaging servers may store proprietary or sensitive information.
For this or for other reasons, organization B may be unwilling to allow entities
outside firewall 62B to have direct access to messaging server B or any other
messaging server 66. This can be one of the principal reasons for which firewall
62B is used by organization B. Moreover, security issues associated with
messaging servers 66 and other network servers have been largely responsible for
the previous general unavailability of instant messaging over the Internet
between organizations.
Bridgehead server B (68B) and other bridgehead
servers 68 in the network environment allow real-time messages to be sent to
message servers 66 without allowing entities outside the corresponding firewall
62 to directly access the messaging server 66 associated with the recipient
client. Moreover, the sending client does not need to know the identity or the
address of the messaging server 66 associated with the recipient client. Indeed,
the addresses of the messaging servers do not need to be published outside of
the firewall.
In the example of FIG. 3, client A composes message 100
and includes therein information 102 identifying recipient client B and the
address 104 of a pool of one or more bridgehead servers at network 60B, any of
which is capable of distributing messages to client B. Because a "pool" of
bridgehead servers can include a single bridgehead server or multiple bridgehead
servers, address 104 is accurately described as relating to a pool, regardless
of whether there is only one or more than one bridgehead server at network 60B
that has the address. In the illustrated example, client A includes a recipient
client identifier 102 identifying client B and the address 104 of bridgehead
server B in message 100.
Referring to FIG. 2, bridgehead server B serves
as a common address for all clients 64 that are linked thereto in the
hierarchical structure. From the standpoint of client A, the step of including
recipient client identifier 102 and the address 104 of bridgehead server B could
merely involve selecting the name of client B from an address book or otherwise
addressing message 100 in ways that are easily understood by Internet users.
Moreover, recipient client identifier 102 and bridgehead server address 104 can
be implemented using conventional Internet resource location protocols that have
been adapted to support the invention, and which will be understood by those
skilled in the art upon learning of the disclosure made herein.
Turning
again to FIG. 3, the path of message 100 as it is transmitted from client A to
client B is represented by the directional arrows designated as 70A-F. Message
100 can be directly transmitted from client A to firewall 62A as shown at 70A,
bypassing the messaging server A and bridgehead server A that are otherwise
associated with client A. Bypassing these network components further reduces
transmission latency. Alternately, however, the path of message 100 between
client A and firewall 62A can pass through either or both of messaging server A
and bridgehead server A.
Message 100 is then transmitted over the
Internet 80 to network 60B as shown at 70B and 70C. Bridgehead server B is
exposed through firewall 62B in the sense that incoming communication addressed
to bridgehead server B is generally authorized to pass through firewall 62B.
Thus, message 100 arrives at bridgehead server B through firewall 62B as shown
at 70D.
As previously noted, the invention can be practiced in the
absence of a firewall 62B at the recipient client's network. In this situation,
bridgehead server B can forward messages to the appropriate messaging server 66
as has been described. Alternately, in the absence of a firewall, bridgehead
server B can notify the sending client A of a direct address of the recipient
client B, thereby enabling client A to directly send messages to client B.
FIG. 4 illustrates the processing that is performed at bridgehead server
B upon receipt of a message according to one embodiment of the invention.
Message 100 includes the recipient identifier 102 and the bridgehead server
address 104 that were designated by the sending client. Upon receiving message
100, bridgehead server B resolves the address of messaging server B based, at
least in part, on recipient identifier 102. For example, bridgehead server B has
a corresponding directory 106 that includes directory information wherein the
clients that are associated with bridgehead server B are referenced with the
messaging servers to which they are assigned. Thus, bridgehead server B can
compare recipient identifier 102 with the directory information included in
directory 106, thereby identifying messaging server B as the destination to
which message 100 will be forwarded and locating the unique address associated
with messaging server B. Once the address of messaging server B has been
resolved, a routing module 108 or another component of bridgehead server B
causes message 100 to be transmitted to messaging server B as shown at 70E.
Referring again to FIG. 3, messaging server B, having received message
100, transmits the message to client B if client B is online. Because messaging
server B may be assigned to multiple clients 64, messaging server B resolves the
identity of the recipient client (e.g., client B) using recipient client
identifier 102 or by any other desired means. When client B receives message
100, it can open a popup window on the user's screen using standard user
interface techniques. For instance, on Windows systems, client B can call
functions resident in the Microsoft Foundation Classes (MFC) supplied by
Microsoft Corp. of Redmond, Wash., to create a window of a specified size,
display it on the screen, overlay it on top of the other applications, and paint
the message content as well as some action buttons (e.g. "Done", "Reply", etc.)
on the window. Alternately, client B can sound an audible signal or perform any
other action to notify the user of message 100 such as, for example, updating a
buddy list to reflect a change in online status indicated in the message 100.
Client B can then process message 100 as desired, including possibly
sending a response to the message. When client B sends a response to message
100, client B becomes the sending client, while client A becomes the recipient
client. The response can be transmitted in substantially the same manner from
client B to client A as original message 100 was sent from client A to client B
as shown in FIG. 3. In other words, client B composes a message in response to
original message 100, includes therein the address of bridgehead server A and a
recipient client identifier designating client A as the recipient, and sends the
response through the Internet to network 60A. The path of the response can be
similar to path 70A-F in that it can bypass message server B and bridgehead
server B at network 60B. Transmitting messages and responses in this manner
enables clients A and B to engage in two-way, real-time communication through
firewalls 62.
Message Forwarding Subscriptions
Methods and
systems for subscribing to information from a remote device are now described.
The subscription may be for the remote device to generate a message if certain
preconditions are met. This type of subscription is termed a "property
notification subscription" and will be described in detail further below. The
subscription may also be for the remote device to forward any messages that the
remote device has received or will receive. This type of subscription is termed
a "message forwarding subscription" and is now described in detail in the
context of FIG. 3.
Message forwarding subscriptions might best be
understood by describing one of its fundamental applications. Suppose that the
user at client A named Wanda is traveling and normally works at client B. The
user might like to keep apprised of the messages being sent to her normal
messaging server B. To accomplish this message forwarding, client A constructs a
message 100 that indicates that messages for the user that are at the messaging
server B are to be immediately forwarded to client A.
A data structure
for such a variation of message 100 is shown in FIG. 5 as a subscription request
110. The subscription request 110 includes a function identifier 112, a
destination address 114, an object identifier 116, a forwarding address 118, and
possibly additional parameters 120. If the remote forwarding device is disposed
within organization B of FIG. 3 as is messaging server B, then the destination
address 114 includes the recipient identifier 102 and bridgehead server address
104. Once the subscription message 110 is constructed, the client A then
transmits the subscription message 110 to the messaging server B in the manner
described above for message 100.
If the remote forwarding device is not
disposed behind a firewall, the destination address 114 may be the address of
the remote forwarding device itself, rather than that of the bridgehead server.
The subscription request 110 may be in the form of an Internet protocol such as
HTTP, or an extension thereof, and take generally the following form:
As a specific example, assume that the URL address of the user's
normal messaging server (i.e., messaging server B) is
http://www.messagingserverB.com, and that the object to which the user's message
are sent is http://www.messagingserverB.com/wanda. Assume also that the URL
address of the device at which the user is currently located is
http://www.clientA.com. In this case, the following might be the subscription
request 110:
In this example, "SUBSCRIBE" and "Subscription Type: forward
messages" are the function identifier 112 indicating that the message is a
message forwarding subscription request. "http://www.messagingserverB.com" is
the destination address 114. "/wanda" is the object identifier 116. The
Call-Back address has, in this example, a subdirectory identifier
"wandamessages" that enables forwarded messages to arrive at a location that
will be accessible by wanda. Alternatively, to address through the bridgehead
server B, the message forwarding subscription request 110 might be as follows:
In this example, http://www.bridgeheadserverB.com may be viewed as
the destination address 114. From client A's viewpoint, "/wanda" is an object
identifier 116 of the bridgehead server B and thus the bridgehead server B would
be viewed as the forwarding device. In actuality, although transparent to the
client A, the bridgehead server B routes the subscription request 110 to the
messaging server B that actually forwards the messages.
In both of the
above examples, http://www.clientA.com/wandamessages is the forwarding address
118. If the client A exists within a firewall protected by bridgehead server A
having an address http://www.bridgeheadserverA.com, the forwarding address 118
might be http://www.bridgeheadserverA.com/clientA/wandamessages. Some types of
additional optional parameters 120 will be described further below.
FIG.
6 illustrates the processing that is performed at messaging server B upon
receipt of the message forwarding subscription request 110 according to one
embodiment of the invention. The destination address 114 (FIG. 5) of the message
forwarding subscription request 110 is used to route the message forwarding
subscription request 110 to the messaging server B. The forwarding message
server B has a memory 120 which has computer executable instructions which, when
executed by a processor 122, perform steps now described.
The messaging
server B recognizes the subscription request 110 as a message forwarding
subscription request by the presence of the function identifier 112 (FIG. 5)
indicating such a request. This recognition prompts the messaging server B to
check the object identified by the object identifier 116 (i.e., wanda) for
messages. The messaging server B sends any messages 124 for the user to the
device (i.e., client A) associated with the forwarding address 118 along with a
subscription identifier 126.
The messaging server B continues to forward
messages as they are received to the forwarding address 118 until the messaging
server B receives a messaging forward unsubscribe request along with the
subscription identifier 126. The message server B will also stop forwarding
messages if the forward message request 110 includes an optional parameter 120
indicating a subscription lifetime. Such a subscription might appear as follows:
In this example, the messaging server B will continue to forward
messages for only 3600 seconds (i.e., 1 hour) even without a message forwarding
unsubscribe request. In this case, the messaging server B includes
computer-executable instructions for terminating the forwarding of messages
after the subscription lifetime has elapsed.
The benefit of this limited
lifetime feature is that it allows servers to clean out unwanted subscriptions
even if the client cannot be trusted to retract the subscription when the client
is done with the subscription. This is important since the sending of
notification when a subscription is active takes up computer and network
resources. If the client wants to retain the subscription, the client must
resubscribe periodically.
FIG. 7 illustrates a network of devices
130-134, device 130 having address http://www.130.com, device 131 having address
http://www.131.com, device 132 having address http://www. 132.com, device 133
having address http://www. 133.com, and device 134 having address
http://www.134.com. As described below, the message forwarding subscription
request 110 can forward messages to any device, not just the device at which the
user is currently working. Furthermore, multiple subscription requests can be
used to establish a group of people that are to receive messages.
In
FIG. 7, a user at device 130 can send three subscription requests 110 to device
131 so that device 131 forwards messages from within a object called
"/groupmessage" to devices 132, 133 and 134. This may be accomplished by issuing
the following subscription requests from the device 130.
Thus, any messages that are posted to the object "groupmessages"
at the device 131 are immediately forwarded to the devices 132, 133 and 134. In
an alternative embodiment, a subscribe message is issued for each of these three
devices 132, 133 and 134.
Property Notification Subscriptions
Property notification subscriptions allow for messages to be generated
and forwarded by a remote device when certain triggering conditions are met. The
triggering condition may be, for example, a property change associated with the
remote device. The properties can be as varied as the online status of the
client, the value of a stock, the physical condition of a person monitored with
medical equipment, the amount of product with which a vending machine is
stocked, or any other measurable condition that might be imagined. Thus, the
invention enables event-driven notifications to be instantly communicated from
one network to another, even if one or both of the networks are protected by
firewalls.
First, an example of a property subscription process for an
online status is described. Next, the subscription process for other sample
properties is described. Subscribing to the online status of another client is
useful in the context of instant messaging. If a recipient client is online, the
recipient can promptly read and respond to messages, thereby allowing real-time
communication to be established over the Internet between clients at different
networks and organizations. Notification of changes in the online status of
clients can be communicated from one network to another in substantially the
same manner as the other instant messages disclosed herein. Specifically, the
notification can be sent to a bridgehead server at the recipient's network, and
is then appropriately forwarded to the recipient according to the methods
disclosed herein in reference to message transmission.
Referring to FIG.
8, contact lists 140 having online statuses are akin to a phone book that is
initially empty and gradually accumulates contact information for associated
clients. For instance, as client A corresponds with other clients or as client A
decides to add a correspondent to contact list 140A, entries 142 are added to
the contact list 140A. In this example, client A has designated clients B, C, E,
F, and G as correspondents, and corresponding entries 142 have been added to
contact list 140A. These clients can be associated with the same messaging
server or the same bridgehead server as client A, or instead may reside at a
different network than client A. Client C resides at network 60C administered by
organization C, while the other clients, namely clients B, E, F, G, and H, are
not illustrated in FIG. 8.
Each entry 142 is associated with an online
status property 144, the value of which indicates whether the correspondent is
online. For instance, in FIG. 8, client entries 142 of contact list 140A
designating clients C and F have an online status property value 144 indicating
that the clients are online (as indicated by the "x"). In contrast, client
entries 142 that designate clients B, E, and G have an online status property
value 144 indicating that these clients are not online (as indicated by the
absence of an "x"). By referring to online statuses of contact list 140A, the
user of client A can immediately know whether particular correspondents are
online and therefore available to engage in real-time communication over the
Internet or any other network such as a private corporate LAN. Although the
entry 142 is described as indicating an on-line status, the entry 142 may even
have other status values such as "away", "busy", "idle", "on the phone" and so
forth.
The values of online properties 144 are set in cooperation with a
subscriber list managed by the messaging server associated with the clients
designated by client entries 142 and the online status property For example,
subscriber list 146C associated with client C has an entry 148C indicating that
client A has subscribed to the online status property of client C (because
client A has designated client C as a correspondent). Entry 148C is used by
messaging server 66C to notify messaging server 66A each time the online status
property of client C changes (because client C logs on or logs off)thereby
allowing client A to update its contact list 140A. Similarly, client C has
designated client A as a correspondent in its contact list 140C. Accordingly,
subscriber list 146A includes an entry 148A indicating that client C has
subscribed to the online status property of client A.
When a client logs
on to its messaging server, the messaging server refers to the subscriber list
associated with the client to determine which other clients have designated the
client as a correspondent. In the example of FIG. 8, client A logs on to
messaging server 66A. Messaging server 66A then refers to subscriber list 146A
and finds that client C has subscribed to the online status property of client
A. Messaging server 66A then sends notification of the online status of client A
to messaging server 66C by way of bridgehead server 68C. The notification is
sent through firewall 62C to bridgehead server 68C in a similar fashion as
messages (e.g., message 100 of FIG. 4) are sent to a bridgehead server.
Moreover, bridgehead server 68C resolves the address of messaging server 66C
according to the address resolution techniques disclosed herein. In this manner,
messaging server 66A can notify messaging server 66C of the online status of
client A over the Internet and through firewall 62C without having to know the
identity or address of messaging server 66C. The entry associated with client A
at contact list 140C is updated to show that client A is logged on to its
messaging server. When client A logs off or otherwise is disconnected from
message server 66A, message server 66A sends notification of this event to
messaging server 66C by way of bridgehead server 68C. The online status of
client A can thereby be communicated or continuously displayed to the user of
client C such that the user of client C knows when client A is available to
engage in real-time communication Subscriber list 146C can be used in a like
manner to update the online status of client C at contact list 140A.
Although an actual notification may be sent to client A (or to the
server of client C) to indicate that client C has logged off as described above,
sometimes client C may be disconnected from the message without such a message
being sent. In one embodiment, when client C logs on, client C sends an event
notification to client A (or the server of client C) indicating that client C
has logged on, but indicating if client C does not send client A (or the server
of client C) an acknowledgement signal within a predetermined time period, then
client A (or the server of client C) should register client C as being offline.
In this case, client C periodically sends notifications to client A (or client
C) registering client C as being online. Thus, if client C is disconnected and
an event notification indicating that client C is off-line is not dispatched to
client A (or the server of client C), client C will be registered as being
offline.
The contact list entries 142 can be created by the user of the
associated client as desired as the user designates clients as correspondents.
Alternately, an entry 142 can be created for a recipient client each time the
client sends a message to a new recipient client. In either case, after being
initially added to a contact list, entries 142 remain on the list unless
explicitly removed by the client. Thus, the contact list can be persistent
through logoffs and subsequent logins. The location of contact lists 140 and
subscriber lists 146 is not critical. For example, while contact lists 140A and
140C are illustrated in FIG. 8 as being located at clients A and C,
respectively, the contact lists can instead be stored at another network
location.
The subscriber lists 146 are generated by each of the clients
in the list sending a property notification subscribe request 110 to the
corresponding client A. The property notification subscription request 110 is
structured as shown in FIG. 5. For example, in order to be placed in the
subscriber list 146A of client A, client C (or any other device) may have sent
the following subscribe request to the messaging server A:
Here, "Property Condition: online status change" is an additional
parameter 120 which indicates the condition that must occur before the online
status property notification is generated and transmitted to the call-back
address. "Message Content: onlinestatus" is also an additional parameter 120
that indicates that the message content includes whether the client C is online.
"Subscription Type: property notify" means that the request command is for the
device to send the message content to the call-back address whenever the
property condition occurs.
The subscription process for properties other
than the online status is now described. In accordance with the present
invention, client A may be notified of any desired property condition of any
device to which client A is given security access. The number of properties and
devices to which client A can subscribe is enormous. All that is necessary is
that client A be able to send a subscribe message to the device, that the device
measures or otherwise has notice of the value of the property desired, that
client A properly addresses the object having the desired property, and that the
device can send messages about the property to client A.
For example,
suppose that the notification device is a health monitor (e.g., at
http://www.healthmonitor.com) monitoring various aspects of a patient's health.
A property of the heart monitor might be the patient's heart rate (at object
http://www.healthmonitor.com/heartrate), and a target device might be a doctor's
text pager (at http://www.massgeneral.gov/gooddoctorpager). The property event
that might trigger a property notification might be simply a change in the
property value. For example, every time the patient's heart rate changes, the
doctor is instantly notified of the change. An example of a subscription message
110 that might accomplish this is as follows:
The headers of the above SUBSCRIBE command may also include the
format of the property notification. For example, the user at client A may just
want a number indicating beats per minute.
The property event that would
trigger a property notification might also be that the heart rate has another
predetermined characteristic such as the heart rate falling outside of a given
safe range. Thus, a doctor can be notified quickly when the patient's health or
life is in jeopardy. An example of a subscription message 110 that might
accomplish this is as follows:
Here, the health monitor sends a message "ALERT, Unsafe Heart
Rate" to the doctor's text pager when the health monitor measures or otherwise
has notice of a heart rate less than 40 or greater than 150.
FIG. 8
shows that Client A has a property contact list 150A identifying the client
(left column), the property (middle column), and the property value (right
column). For example, client A subscribes to the heart rate measured by the
health monitor (client J) which has a value of 60. Client A also subscribes to
the inventory level of client K, an automated soda machine, which has 5 cans in
it. Client A also subscribes to a stock price monitored by Client L, which
indicates a price of 36. Client A could also subscribe to any quantity
measurable by other clients as desired. Client A may also be capable of
measuring quantities such as typing speed per minute. In that case, client C has
subscribed to the typing speed measured by client A as indicated in the property
contact list 150C Client A also has a property subscriber list 156A indicating
that client C has subscribed to the typing speed measured by client A. Clients
B, C, E, F, G, H, J, K and L may also have similar property subscription lists
and property subscriber lists to keep track of the property notifications that
should be sent.
Thus, the present invention enables subscriptions to
property conditions and messages present at remote devices without requiring
complex and complicated broadcasting software. Furthermore, these subscriptions
are enabled whether or not one or both of the devices is behind a firewall.
The present invention also allows great flexibility in routing property
notifications and other electronic messages as illustrated in FIG. 9. The
example of FIG. 9 represents one of an essentially unlimited number of network
and device configurations through which property notifications and other
electronic messages may be routed. Device 135 issues three subscription requests
resulting in a property notification message being routed from device 136,
through device 137, through device 138, and to device 135. To accomplish this,
device 135 issues a property notification subscription request to device 136
resulting in device 136 transmitting a property notification message to the
device 137 according to methods described above. The device 135 also issues a
message forwarding subscription request to the device 137 causing the device 137
to forwarding messages, including the property notification message, to the
device 138. The device 135 also issues another message forwarding subscription
request to the device 138 causing the device 138 to forward messages, including
the property notification message, to the device 135.
The present
invention may be embodied in other specific forms without departing from its
spirit or essential characteristics. The described embodiments are to be
considered in all respects only as illustrative and not restrictive. The scope
of the invention is, therefore, indicated by the appended claims rather than by
the foregoing description. All changes which come within the meaning and range
of equivalency of the claims are to be embraced within their scope.
