U.S. patent application number 10/260063 was filed with the patent office on 2006-06-29 for system and method for efficiently managing data transports.
Invention is credited to Jeffrey Bush.
Application Number | 20060143294 10/260063 |
Document ID | / |
Family ID | 32041798 |
Filed Date | 2006-06-29 |
United States Patent
Application |
20060143294 |
Kind Code |
A1 |
Bush; Jeffrey |
June 29, 2006 |
SYSTEM AND METHOD FOR EFFICIENTLY MANAGING DATA TRANSPORTS
Abstract
A system is described for allocating bandwidth comprising: a
transport layer to support a first socket connection for a first
application and a second socket connection for a second
application; and a socket prioritization module to allocate
relatively more bandwidth to the first socket connection relative
to the second socket connection, wherein allocation of bandwidth is
based on one or more characteristics of the first application
and/or the second application.
Inventors: |
Bush; Jeffrey; (Palo Alto,
CA) |
Correspondence
Address: |
Thomas C. Webster;Blakely, Sokoloff, Taylor & Zafman LLP
Seventh Floor
12400 Wilshire Boulevard
Los Angeles
CA
90025-1030
US
|
Family ID: |
32041798 |
Appl. No.: |
10/260063 |
Filed: |
September 27, 2002 |
Current U.S.
Class: |
709/226 |
Current CPC
Class: |
H04L 47/805 20130101;
H04L 47/824 20130101; H04L 47/193 20130101; H04L 47/70 20130101;
H04L 47/15 20130101; H04W 28/10 20130101; H04L 47/14 20130101; H04L
47/803 20130101; H04L 47/10 20130101; H04L 47/762 20130101 |
Class at
Publication: |
709/226 |
International
Class: |
G06F 15/173 20060101
G06F015/173 |
Claims
1. A method implemented on a data processing device communicatively
coupled to a network comprising: associating interactive
applications with a first type of socket connection and
non-interactive applications with a second type of socket
connection; in response to detecting that an interactive
application needs to transmit or receive data over the network,
opening a first socket connection of the first type for the
interactive application and allocating a first amount of bandwidth
to the first socket connection by setting a maximum data transport
window size for the first socket connection to a first value; in
response to detecting that a non-interactive application needs to
transmit or receive data over the network, opening a second type of
socket connection for the non-interactive application and
allocating a second amount of bandwidth to the second socket
connection by periodically setting a maximum data transport window
size for the second socket connection to a second value and then
resetting the maximum data transport window size to a third value
once a specified amount of data has been transmitted, wherein the
third value is less than the first value and the second value, and
further wherein the second socket connection remains open
concurrently with the first socket connection, and further wherein
the second value is related to how many concurrent socket
connections exist when the second socket connection is initially
opened and a priority associated with each concurrent socket
connection; in response to detecting that a first type of socket
connection is no longer being used by the interactive application,
automatically increasing the second amount of bandwidth to the
second socket connection by increasing the maximum data transport
window size for the second socket connection; and in response to
detecting that a first type of socket connection is again being
used by the interactive application, automatically decreasing the
second amount of bandwidth to the second socket connection by again
periodically setting a maximum data transport window size for the
second socket connection to the second value and then resetting the
maximum data transport window size to a third value once a
specified amount of data has been transmitted, wherein the third
value is less than the first value and the second value, wherein
the increasing the second amount of bandwidth to the second socket
connection automatically increases the maximum data transport
window size of the second socket connection after each of a
plurality of successive predetermined time intervals and
automatically reset the maximum data transport window size of the
second socket connection upon transmitting the second-maximum data
window size amount of data over the second socket connection.
2. The method as in claim 1 wherein the specified amount of data is
equal to said second data transport window size and wherein the
third data transport window size is equal to zero.
3. The method as in claim 1 further comprising: when a first type
of socket connection is being used, maintaining the second amount
of bandwidth allocated to the second socket connection by
periodically resetting said second maximum data transport window
size to zero.
4. The method as in claim 1 further comprising: resetting said
second maximum data transport window size to zero once data from
said second data transport window has been successfully received,
and then periodically resetting said second maximum data transport
window size for said second socket connection to said second
value.
5. The method as in claim 1 wherein said first and second socket
connections are Transmission Control Protocol ("TCP") socket
connections.
6. (canceled)
7. The method as in claim 1 wherein said interactive application is
a Web browser application and said non-interactive application is
an automated software upgrade application.
8.-13. (canceled)
14. A system for allocating bandwidth comprising: a transport layer
to support a first socket connection for a first application and a
second socket connection for a second application, wherein the
second socket connection remains open concurrently with the first
socket connection; and a socket prioritization module to allocate
relatively more bandwidth to said first socket connection relative
to said second socket connection by using a larger maximum data
transport window size for the first socket connection than the
maximum data transport window size used for the second socket
connection, wherein allocation of bandwidth by the socket
prioritization module is in response to detecting that the second
application needs to transmit or receive data over a network, based
on one or more characteristics of said first application and said
second application, and automatically increases the maximum data
transport window size of the second socket connection after each of
a plurality of successive predetermined time intervals and
automatically resets the maximum data transport window size of the
second socket connection upon transmitting the second-maximum data
window size amount of data over the second socket connection,
wherein the maximum data transport window size used for the second
socket connection is related to how many concurrent socket
connections exist when the second socket connection is initially
opened and a priority associated with each concurrent socket
connection.
15. (canceled)
16. The system as in claim 14 wherein after transmitting the
maximum data window size amount of data over the second socket
connection, the maximum data window size is set to zero.
17. The system as in claim 14 wherein allocating bandwidth for said
first socket connection comprises initially setting a first maximum
data transport window size for said first socket connection to a
first value; and wherein allocating bandwidth for said second
socket connection comprises initially setting a second maximum data
transport window size for said second socket connection to a second
value which is smaller than said first value, resetting said second
maximum data transport window size to zero each time data from said
second socket has been successfully received and then periodically
resetting said second maximum data transport window size to said
second value.
18. The system as in claim 14 wherein said first and second socket
connections are Transmission Control Protocol ("TCP") socket
connections.
19. The system as in claim 14 wherein a characteristic of said
first application is that it is a user-interactive network
application and wherein a characteristic of said second type of
application is that it is a non-interactive network
application.
20. The system as in claim 19 wherein said first application is a
Web browser application and said second application is an automated
software upgrade application.
21. A method comprising: in response to detecting that an
application needs to transmit or receive data over a network,
initiating a new socket connection within a network transport layer
on a data processing device; determining whether any other socket
connections are active on said data processing device; comparing a
priority value associated with said new socket connection with said
active socket connections; and in further response to detecting
that the application needs to transmit or receive data over the
network, decreasing bandwidth to an active socket connection of
said active socket connections if said priority value associated
with said new socket connection is higher relative to said active
socket connection, wherein decreasing bandwidth includes
automatically decreasing a maximum data window size of the active
socket connection after each of a plurality of predetermined time
intervals; and automatically resetting the maximum data window size
of the active socket connection upon transmitting the bandwidth of
the active socket of data over the active socket connection, and
further wherein the maximum data window size is related to how many
other active socket connections exist when the active socket
connection is initially opened and the priority value associated
with the active socket connection and each of the other active
socket connections.
22. The method as in claim 21 wherein reallocating bandwidth
comprises dynamically adjusting maximum transport window sizes for
active socket connection.
23. The method as in claim 22 wherein dynamically adjusting
comprises: limiting bandwidth for a first socket connections
relative to said active socket connections by providing said first
socket connection with a relatively smaller transport window size
and/or by resetting said transport window size to zero for said
transport window after all data contained in said active socket
connection has been received and then periodically resetting said
transport window back to said relatively smaller transport window
size.
24. The method as in claim 23 further comprising: providing a
standard maximum transport window size for said active socket
connection and not resetting said maximum transport window sizes to
zero for said active socket connection.
25. The method as in claim 21 wherein said transport layer is a
Transmission Control Protocol ("TCP") transport layer.
Description
BACKGROUND
[0001] 1. Field of the Invention
[0002] This invention relates generally to the field of data
processing systems. More particularly, the invention relates to a
system and method for prioritizing data transports on a data
processing device.
[0003] 2. Description of the Related Art
[0004] A typical layered network architecture is illustrated in
FIG. 1. Each layer within the architecture performs a specific
function to reliably transmit data from a source node 195 (e.g., a
client computer) to a destination node 196 (e.g., a network
server). For example, when an application 190 has data to transmit
to another application 191, the data is processed, in succession by
a transport layer 180, a network layer 170 and a data-link layer
160 before being transmitted over the actual physical connection
165 between the two nodes. At the receiving node 196, the data is
then processed in reverse order, by the data-link layer 161, the
network payer 171, and the transport layer 185 before being handed
off to the receiving application 191.
[0005] The descriptions below assume that the reader has at least a
basic understanding of the functions of each of the network layers.
For those interested, a detailed description of the network layers
defined by the ISO Open Systems Interconnection model can be found
in DILIP C. NAIK, INTERNET STANDARDS AND PROTOCOLS (1998) (see,
e.g., Chapter 1, pages 3-11).
[0006] The well known TCP/IP protocol ("Transmission Control
Protocol/Internet Protocol") operates at the transport and network
layers, respectively. The TCP transport layer is responsible for
ensuring that all data associated with a particular data
transmission arrives reliably and in the correct order at its
destination. Specifically, in order to ensure reliable data
transmission, a virtual connection 187 (also referred to herein as
a "socket connection") is established between a TCP socket 182
opened at the destination transport layer 185 and a TCP socket 181
opened at the source transport layer 180.
[0007] The TCP sockets 181, 182 perform flow control to ensure that
the data transmitted form the source node is provided to the
receiving node at an acceptable data rate. Specifically, a "window"
is established defining the amount of outstanding data a source
node 195 can send before it receives an acknowledgment back from
the receiving node 196 (i.e., indicating that it has successfully
received all or a portion of the data).
[0008] For example if a pair of nodes 195, 196 are initially
communicating over TCP connection that has a TCP window size of 64
KB (kilobytes), the transmitting socket 181 can only send 64 KB of
data and then it must stop and wait for an acknowledgment from the
receiving socket 182 that some or all of the data has been
received. If the receiving socket 182 acknowledges that all of the
data has been received then the transmitting socket 181 is free to
transmit another 64 KB. If, however, the transmitting socket 181
receives an acknowledgment from the receiver that it only received
the first 32 KB (which could happen, for example, if the second 32
KB was still in transit or was lost), then the transmitting socket
181 will only send another 32 KB, since it cannot have more than 64
KB of unacknowledged data outstanding (i.e., the second 32 KB of
data plus the third).
[0009] Thus, the TCP window throttles the transmission speed based
on how quickly the receiving application can process it. The TCP
window is typically defined by a 16-bit TCP header field. As such,
the largest window that can be used for a standard TCP connection
is 2.sup.16 KB (64 KB).
[0010] A client may concurrently have several different socket
connections open with a server or client, or with several different
servers/clients. Each socket connection may not be utilized in the
same manner, however. For example, the user may be interactively
browsing web pages via one socket connection while receiving an
automated software upgrade or e-mail message over another socket
connection. This may result in a degradation of the interactive
user experience, particularly on networks which allocate a
relatively small amount of bandwidth per device (e.g., wireless
networks such as Cellular Digital Packet Data and ARDIS networks).
Under these circumstances, it would be useful to have the ability
to prioritize the socket connections such that the interactive
connections are provided with a relatively larger amount of
bandwidth than the non-interactive connections.
SUMMARY
[0011] A system is described for allocating bandwidth comprising: a
transport layer to support a first socket connection for a first
application and a second socket connection for a second
application; and a socket prioritization module to allocate
relatively more bandwidth to the first socket connection relative
to the second socket connection, wherein allocation of bandwidth is
based on one or more characteristics of the first application
and/or the second application.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] A better understanding of the present invention can be
obtained from the following detailed description in conjunction
with the following drawings, in which:
[0013] FIG. 1 illustrates an exemplary network architecture with a
plurality of network layers.
[0014] FIG. 2 illustrates an exemplary data processing device
communicating with an exemplary data service.
[0015] FIG. 3 illustrates one embodiment of a system for
prioritizing socket connections.
[0016] FIG. 4a illustrates one embodiment of a method for
allocating bandwidth for new background sockets.
[0017] FIG. 4b illustrates one embodiment of a method for
allocating bandwidth for new foreground sockets.
[0018] FIG. 4c illustrates one embodiment of a method for
allocating bandwidth based on relative socket priority.
[0019] FIG. 5 illustrates a technique for allocating bandwidth to a
socket by setting and resetting transport window size.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0020] Described below is a system and method for processing code
words. Throughout the description, for the purposes of explanation,
numerous specific details are set forth in order to provide a
thorough understanding of the present invention. It will be
apparent, however, to one skilled in the art that the present
invention may be practiced without some of these specific details.
In other instances, well-known structures and devices are shown in
block diagram form to avoid obscuring the underlying principles of
the present invention.
Embodiments of a Data Processing Service
[0021] One embodiment of the invention is employed on a wireless
data processing device which operates in conjunction with a data
processing service such as that described in co-pending application
entitled NETWORK PORTAL SYSTEM, APPARATUS AND METHOD, Ser. No.
09/714,897, Filed Nov. 15, 2000 (hereinafter "Network Portal
Application"), which is assigned to the assignee of the present
application and which is incorporated herein by reference. Certain
aspects of this data processing device and data processing service
will now be described, followed by a detailed description of an
advanced system and method for processing data object
identification codes. As an initial matter, however, it should be
noted that the underlying principles of the invention may be
implemented on virtually any type of network and between virtually
any types of network nodes (e.g., networked desktop computers,
networked personal digital assistants, . . . etc).
[0022] FIG. 2 illustrates one embodiment of a data processing
service 100 comprised of one or more servers. The data processing
service provides a portal through which data processing devices 110
may access content (e.g., Web pages, multimedia content, e-mail,
instant messages . . . etc) from external Internet sites 130. In
one embodiment, the service 100 converts standard applications and
data into a format which each wireless data processing device 110
can properly interpret. Thus, as illustrated in FIG. 2, one
embodiment of the service 100 includes a content conversion module
120 for processing requests for Internet content 140. More
particularly, the service 100 acts as a proxy for the data
processing device 110, forwarding Internet requests 140, 141 to the
appropriate Internet site 130 on behalf of the data processing
device 110, receiving responses from the Internet site 130 in a
standard Internet format (e.g., Web pages with embedded audio/video
and graphical content, e-mail messages with attachments, . . .
etc), and converting the standard Internet responses 142 into a
format 143 which the data processing device 110 can process (e.g.,
bytecodes as described in the Network Portal Application).
[0023] For example, the conversion module 120 may include a
hypertext markup language ("HTML") rendering module (not shown) for
interpreting HTML code and downloading any embedded content in the
HTML code (e.g., graphics, video, sound, . . . etc) to the service
100. The conversion module 120 may then combine the HTML code and
embedded content and generate a set of bytecodes for accurately
reproducing the requested content on the data processing device
110. As described above, in one embodiment, the bytecodes may be
Java bytecodes/applets. However, the conversion module 120 may
generate various other types of interpreted and/or non-interpreted
code, depending on the particular type of data processing device
110 being used (e.g., one with an interpreter module or one
without).
[0024] Because one embodiment of the service 100 maintains an
intimate knowledge of the capabilities/configuration of each data
processing device 110 (e.g., screen size, graphics/audio
capabilities, available memory, processing power, user preferences,
. . . etc) it can reconstruct the requested Internet content
accurately, while at the same time minimizing the bandwidth
required to transmit the content to the device 110. For example,
the conversion module 120 may perform pre-scaling and color depth
adjustments to the requested content so that it will be rendered
properly within the data processing device's 110's display. In
making these calculations, the conversion may factor in the memory
and processing power available on the data processing device 110.
In addition, the conversion module 120 may compress the requested
content using a variety of compression techniques, and thereby
preserve network bandwidth.
[0025] In one embodiment, the conversion module 120 will simply
discard Internet content which either cannot be reproduced on the
data processing device 110, or which the user has indicated that
he/she does not want to be reproduced on the wireless device. For
example, a user may indicate that he/she does not want sounds to be
generated on the data processing device 110 or that he/she does not
want advertisements transmitted to the data processing device 110.
The conversion module 120 will then remove any sounds or
advertisements embedded in the requested Web page (or other
requested Internet content). Because HTML rendering and other
advanced processing of Internet content/data is offloaded to the
service 100 as described above, the data processing device 110 can
be manufactured using a relatively low power microprocessor or
microcontroller, thereby lowering the cost of manufacture and/or
the energy consumed by the device 110.
[0026] In one embodiment, when a particular Web page or other
Internet object has been converted into a format suitable for
rendering/execution on the data processing device 110 the formatted
page/object may be stored locally on a cache 125 maintained at the
service 100. The next time the content is requested, the conversion
module 120 may simply read the previously-generated code from the
local cache 125 (i.e., it will no longer need to retrieve the
content from remote locations to reconstruct the code).
Data Transport Prioritization
[0027] One embodiment of a system for prioritizing data transports
(e.g., socket connections) is illustrated generally in FIG. 3. Two
applications 390 and 391 executed on the data processing device 110
are shown communicating with two service modules 392 and 393,
respectively, executed on the service 110. One socket connection,
represented by sockets 310 and 312 in transport layers 305 and 306,
respectively, provides for reliable data communication between
application 390 and service 393. Similarly, a socket connection
supported by sockets 311 and 313 provides for reliable data
communication between application 391 and service 392.
[0028] In one embodiment, the transport layers 305 and 306 provide
all, or a subset of, the standard TCP transport functions. In
addition, the embodiment illustrated in FIG. 3 includes socket
prioritization logic 330 and 331 which prioritizes socket
connections based on a one or more characteristics of the
applications for which they are generated. For example, sockets for
interactive applications such as Web browsing and instant messaging
may be assigned relatively high priorities whereas sockets for
non-interactive applications such as automated software upgrades
may be assigned relatively low priorities. By prioritizing sockets
in this manner, background communication tasks such as automatic
software upgrades may be conducted by the service 100 transparently
to the end user.
[0029] Three embodiments of methods for prioritizing data
transports are illustrated in FIGS. 4a, 4b and 4c. These methods
may be implemented by the specific system architecture illustrated
in FIG. 3, or by a different system architecture. FIGS. 4a and 4b
illustrate methods in which sockets are prioritized as either
"background" sockets or "foreground" sockets. As used herein,
"foreground" sockets are sockets generated for interactive
applications (e.g., Web browsing, instant messaging,. . . etc)
whereas "background" sockets are sockets generated for
non-interactive (or less interactive) applications (e.g., software
upgrades).
[0030] Referring to FIG. 4a, at 405, a new background socket
connection is initiated for a non-interactive application. For
example, a specified portion of the software or firmware on the
data processing device may need to be upgraded by the service 100.
In this case, a background socket connection (e.g., sockets 311,
313) may be established between an upgrade application on the
device 110 (e.g., application 391) and an upgrade service module on
the service 100 (e.g., service module 392).
[0031] At 410, the socket prioritization logic 330, 331 on the
device 110 and/or the service 100, respectively, determines whether
any foreground sockets are currently supporting interactive
applications (e.g., application 390). If not, then at 430, a
background socket is generated for the non-interactive application
with a specified maximum window size (`m`). In one embodiment, the
maximum window size may be set to the maximum size supported by the
transport layer 305, 306 (e.g., 64 KB for standard TCP). In another
embodiment, however, the maximum window size may be limited to a
smaller value (e.g., 8 KB) so that, if/when the user begins
performing interactive functions on the data processing device 110,
the device can respond without an unreasonable delay (i.e., which
might result if the device were required to wait until for a
maximum-sized window to be received before initiating the
foreground socket).
[0032] At 410, if the socket prioritization logic 330, 331
determines that foreground sockets exist, then at 420, the
background socket may be generated with a relatively smaller
maximum window size (`n`). In one embodiment, the maximum window
size n is set to zero. However, in another embodiment, the maximum
window size may be set to a relatively small value (e.g., 2
KB).
[0033] Moreover, in one embodiment, in order to allocate a specific
percentage of the overall bandwidth to the background socket, the
maximum window size for that socket may be reset to zero
periodically. For example, if the total bandwidth available to the
data processing device is 32 KB/sec, to allocate 1/4 of the total
bandwidth to a background socket, the socket prioritization logic
330, 331 may set the maximum window size to 8K once each second.
When the 8 K has been transmitted successfully (presumably in less
than 1 second), the socket prioritization logic 330, 331 resets the
maximum window size to zero until the beginning of the next second.
This technique of precisely allocating a percentage of the overall
bandwidth to a socket is illustrated graphically in FIG. 5. This
bandwidth allocation technique may be employed at the various
stages described herein where the maximum window size of a socket
is set to a particular value (e.g., at 420 in FIG. 4a).
[0034] The socket prioritization logic 330, 331 may monitor the
foreground socket connections to determine whether the user is
still working interactively on the device 110. For example, in one
embodiment, a foreground inactivity timer is reset to a threshold
value (e.g., 30 seconds) each time the foreground socket is
utilized (e.g., each time the user clicks on a new URL to a Web
page). If the foreground socket is not utilized for the threshold
period of time, determined at 425, then the maximum window size of
the background socket may be increased (e.g., and reset to zero
periodically based on the percentage of bandwidth to be allocated,
as described above).
[0035] In the embodiment illustrated in FIG. 4a, the maximum window
size is increased to `m` if the inactivity threshold is reached
(i.e., the value to which the maximum window size is set if no
foreground sockets are initially detected). It should be noted,
however, that the maximum window size may be increased to alternate
values while still complying with the underlying principles of the
invention. In one embodiment, the maximum window size may be
increased incrementally over time, under the assumption that the
longer the foreground socket is inactive, the less likely it is
that the foreground socket will become active at any given point in
time.
[0036] FIG. 4b illustrates a similar method for initiating a new
foreground socket. At 440, the new foreground socket is initiated.
If no background sockets exist, determined at 445, then at 447 the
foreground socket is generated using a specified window size (e.g.,
32 KB, 64 KB, . . . etc). If, however, background sockets exist,
then the socket prioritization logic 330, 331 may reduce the
bandwidth allocated to those sockets to free up bandwidth for the
new foreground socket. Thus, at 450, the maximum window size for
the background socket is set to `n` and periodically reset to zero
(as described above) to free up bandwidth. Once again, if the
foreground socket becomes inactive, determined at 455, then the
background socket window size may be reset to a larger value at 460
so that the background application can consume the additional,
unused bandwidth.
[0037] In one embodiment of the invention, sockets are not strictly
classified as "background" or "foreground" sockets as described
above. Rather, sockets may be assigned a relative priority value
(e.g., between 1 and 4) based on the level of interactivity of the
applications which they support (or based on other specified
variables).
[0038] One embodiment of a method for prioritizing socket
connections in this manner is illustrated in FIG. 4c. At 470 a new
socket connection is initiated with a specified priority (`x`). At
475, the socket prioritization logic 330, 331 determines whether
any other active sockets exist. If not, then the new socket is
initiated in a typical manner, using a specified window size at
477.
[0039] If, however, active socket connections exist between the
device 110 and the service 100 (or a different client/server) then,
at 480, the priorities of all of the socket connections are
evaluated and, at 485, the maximum window sizes are reallocated
based on the relative priorities of the active sockets. For
example, if three sockets exist having relative priorities of 1, 2
and 3 (with 1 being the highest priority and 3 being the lowest)
then the socket with a priority of 1 may be allocated a larger
window size than the socket with a priority of 2, and the socket
with a priority of 2 may be allocated a larger window size than the
socket with a priority of 4. If the maximum available bandwidth is
64 KB/sec, then the highest priority (1) socket may be allocated,
for example, a 40 KB window, the lowest priority (3) socket may be
allocated an 8 KB window and the socket with an intermediate
priority (2) may be allocated a 16 KB window. If each socket is
reset to zero each second as described above, then the 64 KB/sec
bandwidth will be accurately divided among the sockets based on
relative priority. In one embodiment, however, the highest priority
socket may not be periodically reset to zero as described, so that
it will be provided with the maximum available bandwidth.
[0040] Once again, if a particular socket becomes inactive for a
predetermined period of time (e.g., because a user stops
interactively working on an application), determined at 490, then,
at 495, the window sizes for the remaining active sockets may be
reallocated based on their relative priorities (as described
above).
[0041] Embodiments of the invention may include various steps as
set forth above. The steps may be embodied in machine-executable
instructions which cause a general-purpose or special-purpose
processor to perform certain steps. Alternatively, these steps may
be performed by specific hardware components that contain hardwired
logic for performing the steps, or by any combination of programmed
computer components and custom hardware components.
[0042] Elements of the present invention may also be provided as a
machine-readable medium for storing the machine-executable
instructions. The machine-readable medium may include, but is not
limited to, floppy diskettes, optical disks, CD-ROMs, and
magneto-optical disks, ROMs, RAMs, EPROMs, EEPROMs, magnetic or
optical cards, propagation media or other type of media suitable
for storing or transmitting electronic instructions. For example,
the present invention may be downloaded as a computer program which
may be transferred from a remote computer (e.g., a server) to a
requesting computer (e.g., a client) by way of data signals
embodied in a carrier wave or other propagation medium via a
communication link (e.g., a modem or network connection).
[0043] Throughout the foregoing description, for the purposes of
explanation, numerous specific details were set forth in order to
provide a thorough understanding of the invention. It will be
apparent, however, to one skilled in the art that the invention may
be practiced without some of these specific details. For example,
while embodiments of the invention described above operate at the
TCP transport layer, the underlying principles of the invention are
not limited to any particular data transport or any particular
network layer. Moreover, while described above in the context of a
data processing device 110 communicating with a data service 100,
the underlying principles of the invention may be employed between
virtually any two nodes communicating over a data network.
Accordingly, the scope and spirit of the invention should be judged
in terms of the claims which follow.
* * * * *