Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02410866 2010-06-21
CLIENT SIDE DETERMINISTIC ROUTING AND TRANSPARENT
REDIRECTION
BACKGROUND OF THE INVENTION
This invention relates in general to content distribution and, more
specifically, to offloading distribution from content providers to content
distributors.
There is a desire to provide content files over the Internet. In general, the
Internet is an adequate medium for providing content files, however, it is a
poor medium
for transferring content files such as video and audio. Unlike other content
files, video
and audio must not only be transferred over the Internet, they must be
transferred in a
way that provides Quality of Service (QOS) to a requestor. To provide QOS,
content
providers employ various schemes. For example, a content provider may provide
content
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via multiple sources. Use of multiple sources reduces the load at any single
source,
which in theory improves QOS. Further improvements include determining which
source
is least loaded and directing content requests to that source. Alternatively,
content files
are provided from a source physically located closest to a perceived
geographic location
of the requestor. While each of these methods offers potential QOS increases,
they are all
unpredictable as information about a requestor is both speculative and
incomplete.
In addition to the unpredictable nature of the aforementioned schemes,
each scheme requires involvement by the content provider. This involvement
necessitates
undesirable costs in the form of support, equipment and distraction. These
costs are
particularly burdensome to small content providers. Thus, it is desirable
provide content
distribution which improves QOS while minimizing involvement by a content
provider.
SUMMARY OF THE INVENTION
An embodiment of the present invention provides a method for promoting
distribution of content objects from a content object source to a client
computer via a
content distribution system. The method comprises associating a content object
source
with a transfer node. The association between the content object source and
the transfer
node is indicated to the client computer. When the client computer receives a
request for
a content object available from the content object source, the request is
fulfilled by the
transfer node where the requested content object source is the same as the
associated
content object source.
Reference to the remaining portions of the specification, including the
drawings and claims, will realize other features and advantages of the present
invention.
Further features and advantages of the present invention, as well as the
structure and
operation of various embodiments of the present invention, are described in
detail below
with respect to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a block diagram of an embodiment of a content distribution
system;
Fig. 2 is a block diagram of an embodiment of an active directory portion
of the content distribution system;
Fig. 3A is a block diagram of an embodiment of an origin server portion of
the content distribution system;
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Fig. 3B is a block diagram of an embodiment of an external origin server
portion of the content distribution system;'
Fig. 4A is a block diagram of an embodiment of a content exchange
portion of the content distribution system;
Fig. 4B is a block diagram of another embodiment of a content exchange
portion of the content distribution system;
Fig. 4C is a block diagram of an embodiment of a content exchange site
including multiple content exchange servers;
Fig. 5 is a block diagram of an embodiment of a client computer portion of
the content distribution system;
Fig. 6 is a block diagram of an embodiment of a content distribution
system;
Fig. 7A is a first portion of a flow diagram of an embodiment of a process
for distributing content to a user;
Fig. 7B is a second portion of the flow diagram of Fig. 7A;
Fig. 8 is a block diagram of an embodiment of a viewer object proxy;
Fig. 9 is a flow diagram of a viewer object proxy background application;
Fig. 10 is a flow diagram of a viewer object proxy request servicing;
Fig. 11 is a flow diagram of an embodiment of a method for tracking
content between an origin server and a content exchange;
Fig. 12 is a flow diagram of an embodiment of a process for
communicating information from a content manger to a server manager;
Fig. 13 is an embodiment of a flow diagram of a process for publishing
information by a content manger to a server manager;
Fig. 14 is a block diagram of an embodiment of the content exchange
which shows multiple providers connected through separate ports;
Fig. 15 is a block diagram of another embodiment of the content exchange
which shows multiple providers connected through separate addresses;
Fig. 16 is a hierarchical representation of an embodiment of grouping of
providers and content exchanges; and
Fig. 17 is a hierarchical representation of another embodiment of grouping
of providers and content exchanges.
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DESCRIPTION OF THE SPECIFIC EMBODIMENTS
The present invention enables content object providers to offload content
object distribution responsibility to a content object distributor. Further,
the present
invention provides sufficient QOS for offloaded content object transfers.
In the Figures, similar components and/or features may have the same
reference label. Further, various components of the same type may be
distinguished by
following the reference label by a dash and a second label that distinguishes
among the
similar components. If only the first reference label is used in the
specification, the
description is applicable to any one of the similar components having the same
first
reference label irrespective of the second reference label.
Referring to Fig. 1, a block diagram of an embodiment of a content
distribution system 100 is shown. In this embodiment, the content distribution
system
100 includes an active directory 104, one or more origin servers 108, one or
more client
computers 112, one or more content exchanges 116, one or more external origin
servers
118, the Internet 120 and a crawling directory 124. A particular client
computer 112
interacts with the active directory 104`to select a content object for
download. The object
can be played during download if it is streaming media or can be stored for a
later time.
The content object could be any type of information, such as audio, video or
data, that is
available for download from a network. The request for the content object is
forwarded
to the appropriate origin server 108 along with preference information from
the client
computer 112. The origin server 108 decides where the object is downloaded
from. In
order to provide sufficient QOS, any of the content exchanges 116 or even the
origin
server 108 itself could provide the object.
The active directory 104 can be the interface to the client computer 112 for
selecting a content object. Software for both the origin server 108 and
optionally for the
client computer 112 can be downloaded from the active directory 104 to enable
the
content distribution system 100. Either a directory interface page or a search
interface
page may be used to determine the content object desired. The interfaces are
maintained
in an active manner to avoid broken links to content objects on the origin
servers 108.
When a content object is needed from the origin server 108 by a content
exchange 116,
the active directory 104 can provide a path back to the proper origin server
108.
Other embodiments could have multiple active directories. Users of the
system could be divided amongst the several active directories to distribute
the loading.
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Additionally, the other active directories could be used for redundancy such
that if one
active directory were offline, the others would absorb the loading.
In some embodiments, the origin server 108 provides the source of a
content object, directs a user to a preferred source of the content object and
provides
directory information to the active directory 104. Content objects are
introduced to the
system 100 by origin servers 108. Introduction involves selection by an origin
server
administrator of the content objects to make available to the active directory
104. The
administrator is person or system that manages the origin server 108. The
content objects
could include previously stored information or a streaming feed of
information.
According to a predetermined cycle, the origin server 108 provides a catalog
of the
selected information that is updated as the content on the origin server 108
changes.
The origin server 108 determines the preferred source to direct the client
computer 112 to in order to download the content object. The preference list
of the client
computer 112, the loading of the content exchanges and the location of copies
of the
content object are all considerations of the origin server 108 in redirecting
the client
computer to the preferred source of the information. That source could be the
origin
server 108 itself or one of the content exchanges 116.
The user directs the client computer 112 to find the desired content object
and subsequently download that object. Using viewer object proxy software
downloaded
from the active directory 104, the client computer 112 determines the content
exchanges
116 that can deliver content with the adequate QOS. The process of determining
a
content exchange 116 with adequate QOS involves, for example, receiving test
information from the content exchanges that are likely to produce the best
results in
preparing a preferred list. The user can modify the preferred list of content
exchanges
116 if a customized approach is desired. When the origin server 108 is
deciding the
source of the content object, the preference information is used to provide
adequate QOS.
The external origin servers 118 can be additional sources of content
objects available to the client computer 112. In an embodiment, external
origin servers
118 are coupled to a content exchange 116.
The content exchanges 116 are caches for content objects. A number of
these content exchanges 116 are distributed to different points of the
Internet 120 to cache
content objects. Information can be cached based upon a number of
considerations, such
as the desirability of information to users, as a service to origin servers
108 who want
their content readily available to users, or as a service to users who want
improved QOS.
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Grouping of the content exchanges 116 could be in clusters or individually to
service the
demand of client computers 112 for content objects.
When a requested content object or part of a requested content object is
not found by a user requesting it from a content exchange 116, a request by
the content
exchange 116 to other content exchanges is made for that content object. If no
other
content exchanges 116 have the content object, the active directory 104 is
queried for the
origin server 108 who is the source of the content object and the content
object is
downloaded from there. While the content exchange 116 is gathering the content
object,
the client computer 112 is receiving the initial portions that are available.
The content
object could be stored in pieces on several content exchanges 116 and the
requesting
content exchange 116 will retrieve those pieces to reassemble the whole
content object as
needed by the client computer 112.
In some embodiments, when a requested content object or part of a
requested content object is not found by a user requesting it from a content
exchange 116,
a request by the content exchange 116 to an external origin server 118 can be
made
retrieve the requested content object.
A crawling directory 124 is used to supplement the catalog information
reported by the origin servers 108. When searching for content objects for a
user, the
active directory 104 could display content objects available from the origin
servers 108
and other content objects uncovered by the crawling directory 124. By
traversing the
web, crawling directories 124 catalog the content objects and other
information they
encounter. For example, a keyword search of the catalog can direct the user to
a content
object not available from any origin server on the system 100. One of the
content
exchanges 116 could be selected by the active directory 104 to cache the
content object as
the client computer 112 downloads it. Although only one crawling directory 124
is used
in this embodiment, other embodiments could use a number of crawling
directories to
offer additional search results.
The Internet 120 is comprised of servers linked together by routers. Data
is divided into packets that travel through the Internet 120 by hopping from
one router to
the next until the destination is reached. Each packet may take a different
route through
the Internet and arrive at the destination at a different time. Additionally,
some packets
can be lost during travel through the Internet 120 as the bandwidth of any
router saturates.
As the number of hops between the source of a content object and the
destination
increases, so does the likelihood of excessive delay and packet loss.
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As the content object traverses a path from source to destination through
the Internet 120, the smallest bandwidth between any two routers in the path
defines the
maximum bandwidth of that path. Generally, the bandwidth from the Internet 120
to the
client computer has the least bandwidth allocation. At other times, some other
hop
between routers has the smallest bandwidth. Caching the content object in a
content
exchange 116 with a minimal amount of hops between the content exchange 116
and the
client computer 112 improves the likelihood of adequate QOS.
Downloading the content object at a desired data-rate that does not exceed
the data-rate of the client computer to the Internet 120 is adequate QOS. The
maximum
QOS a user can expect is defined by the speed of their network connection, the
processing
power of their computer and other factors. The minimum QOS is subjectively
defined by
the user based upon the quality they desire within certain limits. For
example, a user with
a 400 Kbps network connection and a fast computer may have a choice of a 28
Kbps, 56
Kbps, or 128 Kbps stream for an audio clip from which the user chooses the 128
Kbps
stream. So long as the datarate provided by the client computer is in the
range of 128 -
400 Kbps, adequate QOS is possible for that stream.
Although the above embodiment primarily uses the Internet 120 to
connection between the various blocks, other embodiments could use private
links outside
the Internet 120. Additionally, content objects outside the system 100 could
benefit from
. the system 100 to the extent caching, encryption and compression is
provided.
With reference to Fig. 2, a block diagram of an embodiment of an active
directory portion 104 of the content distribution system 100 is shown.
Included in the
active directory 104 are a dynamic domain name server (DNS) 204, a server
manager
208, a directory page 212, a search page 216, a download page 220, a
subscriber database
224, a server database 228, a content exchange database 232, and a route
database 234.
The content distribution system 100 interacts with the active directory 104 to
provide
directory information to the user and assist in downloading a content object
to the user.
Both the user of the client computer 112 and the administrator of the origin
server 108 are subscribers to the content distribution system 100. Software is
downloaded from a download page to the user and/or administrator. The software
for the
client computer 112 is optional in some embodiments and improves QOS. The
software
for the origin server 108 allows the active directory 104 to update the
content available on
the system 100 and to direct the client computer 112 to a preferred source for
receiving
that content.
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The client computer 112 attaches to the domain of the active directory 104
to find a desired content object. Depending on preference, the user may use a
directory
page 212 or search page 216 to find the content object. The search page 216
may be a
traditional boolean search engine that accesses a catalog of the content
objects provided
by all origin servers 108 as well as information gathered from the crawling
directory 124.
Other embodiments could only display information from the crawling directory
124 after
a search of the content from the origin servers 108 is unsuccessful or omit
information
from the crawling directory 124 altogether. The catalog of content objects for
all origin
servers 108 is maintained in the server database 228.
The directory page 212 organizes the possible content objects in a
hierarchy of categories that are organized by subject. For example, the first
page might
show a number of topics of general interest where the user selects sports. In
the next
page, which is one level down in the hierarchy, a number of sports are
displayed where
the user selects football. Down another level in the hierarchy, the user may
select the San
Diego ChargersTM to see another page of related content object links.
The administrator categorizes the content on the origin server 108 to allow
the directory page 212 to present it properly. On a site, directory or file
basis, the
administrator can choose a category for content objects in an HTML SSI tag
associated
with that content object. This classification is harvested and stored on the
active directory
to. allow presenting content objects in different categories. Additionally, a
moderator may
describe and arrange content objects in the categories for the directory page
212. For
example, the moderator could mark certain content objects for more prominent
display
and/or add a review for the content object.
The server manager 208 maintains information on all client computers
112, all origin servers 108, all external origin servers 118, all content
exchanges 116, and
all content objects on origin servers 108. The information related to client
computers 112
and origin servers 108 is maintained in the subscriber database 224. The full
name, a
login name, a password, a unique identifier, token credits available, and
other information
is maintained in the subscriber database 224 for each user associated with a
client
computer 112. This database 224 also holds the last time the origin server 108
was
verified, an Internet Protocol (IP) address for the origin server 108, the
port the content
manager server runs upon, on-/off-line status of the origin server 108, a
banner ad URL, a
name for the origin server 108, a description of the origin server 108, the
credits or tokens
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needed to use the origin server 108 or other billing model, and the number of
connections
or viewers allowed at one time.
Information on content objects for all origin servers 108 is maintained in
the server database 228. For each content object, the origin server name,
content object
file name and path are stored along with category information, a brief
description and
keywords. The server database 228 is queried to provide content selections to
the user
during navigation of the directory and search pages 212, 216. To maintain
current
information in the server database 228, the server manager 208 periodically
interacts with
the origin server 108 to get the most recent changes to the catalog of content
objects and
to determine if the origin server 108 has gone offline. Whenever an origin
server 108
goes offline, the entries in the server database 228 corresponding to that
origin server 108
are removed and the status information in the subscriber database 224 is
updated.
In some embodiments, the entries in the server database 228 remain even
after the origin server 108 goes offline. The status is updated to reflect
that the content
associated with the origin server is unavailable, but the information remains
stored in the
server database 228. If the status is updated to online, the information is
once again
presented to users that are searching for content objects. In some
circumstances, an origin
server 108 may indicate to the active directory 104 that it is going offline
for a period of
time. Presuming the period of time is short, the active directory can keep
information in
the server database 228 without presenting it to users.
A list of the content exchanges 116 available to the system 100 is
maintained by the server manager 208 in the content exchange database 232. In
some
embodiments, the content exchange database 232 can include a list of IP
addresses for all
possible content exchanges 116 within the content distribution system 100.
Further, the
content exchange database 232 can include a number of content exchange fields
associated with each content exchange 116. For example, fields associated with
each
content exchange 116 in the content exchange database 232 can include a
content
exchange identifier, a content exchange site, a content exchange provider, a
content
exchange name, a content exchange location, a content exchange status, an
icon, or any
other desired or needed information.
Together, the content exchange identifier and content exchange site
identify a unique content exchange 116 at a particular content exchange site.
The content
exchange provider is an indicator of the party responsible for the content
exchange, such
as XYZ company. The content name is a domain name and the content exchange
location
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can be geographic coordinates for a content exchange 116. In an exemplary
embodiment,
the content exchange database 232 includes a content exchange identifier, a
content
exchange site, a content exchange lP address, a content exchange provider, a
content
exchange name, a content exchange location, and an icon for each content
exchange 116
in the content exchange database 232.
In general, the content exchange database 232 can be regionalized or
partitioned by a variety of methods including, but not limited to, improved
QOS criteria
or subscription services criteria. Additionally, the content exchange database
232 can
include a listing of alternative active directories 104, origin servers 108,
or any other
useful or necessary information.
The content exchanges 116 in the system 100 regularly provide status to
the server manager 208. As content exchanges 116 become available or
unavailable, their
operational status is reported to the server manager 208 and recorded in the
content
exchange database 232. In some embodiments, the content exchange database 232
can
include additional status information including content exchange 116 loading,
capacity,
utilization, and health.
The routing database 234 includes a list of external origin servers 118. In
some embodiments, the routing database 234 includes identification, status and
organization information related to the external origin servers 118.
Identification
information can include an IP address and a domain name for an external origin
server
118. Status information can include availability, loading or other status
about the external
origin server. Organization information can include a list of alternative
external origin
servers 118. In an embodiment, the routing database 234 includes an EP address
and a
domain name for each external origin server 118. In some embodiments,
identifying an
external origin server 118 in the routing database 234 is the mechanism for
associating
the external origin server 118 with the content distribution system 100.
For each external origin server 118 in the routing database, there are a list
of user names that are allowed to use a content exchange 116 to access the
information on
the external origin server 118. The user name is unique to the user of the
client computer
112. A list of external origin servers 118 a client computer can route through
a content
exchange is provided to the client computer 112. The client computer 112 uses
the
information from the routing database to redirect user requests for an
external origin
server 118 to a content exchange 116. After the content exchange 116 populates
with the
content objects from the external origin server 118, bandwidth is offloaded
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external origin server 118 to the content exchange 116. The user may pay the
owner of
the content exchange and/or the administrator of the origin server for this
enhanced
service.
The dynamic DNS 204 provides an origin server name for each IP address
for the origin servers 108. The origin server name uniquely identifies the
origin server
108 on the Internet 120. This information is maintained in the subscriber
database 224.
The content exchange 116 does not know the IP address of the origin server 108
that
provided the content object to the content exchange 116, but knows the origin
server
name. When a content exchange 116 wants to populate its cache with a content
object or
a portion of a content object that is not available from other content
exchanges 116, the
dynamic DNS 204 is queried to determine the IP address or domain name of the
origin
server 108 that is the source of the content object. If a domain name is
retrieved from the
dynamic DNS 204 the IP address corresponding to that domain name is retrieved
from a
DNS.
Referring next to Fig. 3A, a block diagram of an embodiment of an origin
server portion 108 of the content distribution system 100 is shown. The origin
server 108
is managed by an administrator and provides one source of content objects to
the content
distribution system 100. QOS is provided by the origin server 108 directing
the client
computer to a content exchange 116 that can efficiently deliver the desired
content object.
Included in the origin server 108 are a content source 304, a content server
308, a content
manager 312, a local content catalog 316, a content location database 320,
content
exchange information 324, and a health check 330.
Content is provided to the origin server 108 by a content source 304. The
content source 304 could be a live web cam, a video or audio feed, a data
object, a data
stream, a video tape or audio tape, an optical or magnetic disk, or any other
content
delivery mechanism. Content objects are delivered by the content source 304 to
the
content server 308 for possible distribution to the system 100.
Time and date information is maintained in each content exchange 116 for
the content objects or portions of content objects maintained therein. The
time and date
information allows distinguishing content objects which may have the same
origin sever
name, path name and file name. Other embodiments could use any unique code
such as a
checksum, CRC or hash to uniquely identify a content object.
All content objects of the origin server 308 are stored on the content server
308. The administrator can select a content object or groups of content
objects for
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publishing to the system 100 while leaving other content objects on the
content server 308
that are unavailable to the system 100. Some content objects are discreet
files, but others
are streams of content produced, for example, by live web cams. The software
that runs
the content server 308 may be integrated with the software of the content
manager 312.
The content manager 312 publishes the desired content objects to the
system 100 and directs users to the preferred content exchange 116 for
downloading
content objects associated with the content manager 312. At the direction of
the
administrator, the content manager 312 selects content objects or groups of
content
objects by filename, directory or drive volume for publishing to the active
directory 104.
Some content objects on the content server 308 may be excluded from publishing
such
that they are not available to the system 100.
The content objects selected for. publishing to the system are maintained in
a local content catalog 316. Entries in the local content catalog 316 are kept
current by
the content manager 312 as the objects corresponding to those entries may
become
unavailable or updated. For each entry, the content object file name and path
are stored
along with category information, a brief description and keywords. Upon
attachment to
the system 100, the local content catalog 316 is sent by the content manager
312 to the
active directory 104 for entry to the server database 228. Periodically,
changes to the
local content catalog 316 are sent to the server database 228 to keep the
directory
information as current as possible. Updates could happen on a regular interval
such as
every two minutes and/or whenever a change in the local content catalog is
made.
The content manager 312 also knows the location of all portions of content
objects associated with that content manager 312. Upon attaching to the system
100, the
content manager 312 contacts each of the content exchanges 116 for status. The
content
exchange 116 periodically reports on its content object or content object
portions to the
associated content managers 312. Armed with this information, the content
manager 312
can direct a client computer 112 to a content exchange 116 that may have some
or all of
the desired content object available for download.
Location information for content objects that is reported by all the content
exchanges 108 is maintained by the content manager in the content location
database 320.
By querying the content location database 320, the content manager 312 can
determine
the content exchanges 116 that contain a content object or a portion of a
content object.
During the routing of the client computer 112 to a content source, the
presence of the
content object in a particular content exchange 112 can affect the routing
determination.
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The content exchange information store 324 holds information on all
active content exchanges 116. Upon power-up of the origin server 108, the
content
exchange database 232 in the active directory 104 is downloaded into the
content
exchange information store 324. All the content exchanges 116 listed in the
content
exchange information store 324 are queried after power-up for status
information that is
retained as content exchange information 324. The status information includes
the
number of concurrent links used, total number of concurrent links allowed,
bandwidth
utilization, and cache chum rate. The chum rate of the cache is the amount of
time
unused data remains in the cache and is indicative of the loading of the
cache. For
example, data is usually flushed out of the cache quickly for content
exchanges 116 that
are busy relative to the amount of storage in the cache. However, some
embodiments that
could have sticky content objects that remains pinned in the content exchange
116 for a
period of time regardless of use.
The content manager 312 intelligently redirects the client computer 112
wanting a content object to the preferred source for that object. Preference
information
provided from the client computer 112 is used to determine the sources of the
content
object preferred by the client computer 112. This information is used along
with the
current locations of the content object and the loading of the possible
content exchanges
in order to direct the client computer 112 to the preferred content exchange
116 for
download of the content object.
In some embodiments, the content manager 312 can regulate access to
content objects. When a client computer 112 attempts to download a content
object
associated with a content manager 312, a login dialog can be presented if the
administrator has secured the content object. The user may enter a user name
and/or
password in the login dialog to enable redirection of the client computer 112
to a source
for the content object. This username and/or password is in addition to any
required for
the active directory 104. Before redirecting the client computer 112 to that
source, the
user name and/or password or login information is checked against a list of
acceptable
login information previously stored on- the origin server 108. Access to a
whole origin
server 108 or a volume, a directory or a content object on the origin server
108 may be
regulated in this manner.
Some embodiments, allow the origin server 108 or active directory 104 to
preload content objects on a content exchange 116. The requests for content
objects are
monitored to determine desirability. Desirability information, billing
information and/or
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other considerations are used to determine which content objects to preload on
a content
exchange 116. Either the origin server 108 or active directory 104 can request
the content
objects from a content exchange 116 to preload them there. Periodically, the
content
objects could be requested to keep them loaded on the content exchange such
that they
are not unloaded because of inactivity.
The health check 330 can be either a hardware or software application
which provides operational characteristics of an associated origin server 108.
In an
embodiment, the health check 330 provides a single indication of origin server
108 status.
The single indication is a normalized value between zero and one indicating a
combination of origin server characteristics. For example, it could include a
CPU load, a
CPU temperature, a number of concurrent connections, and/or a number of
requests an
origin server is facilitating. In an alternate embodiment, the health check
330 could
monitor characteristics of a content exchange 116 while running on another
content
exchange 116 or origin server 108.
Referring next to Fig. 3B, a block diagram of an embodiment of an
external origin server portion 118 of the content distribution system 100 is
shown. The
external origin server 118 differs from the origin server 108 in that the
external origin
server 118 does not have content manager software installed upon it. Included
in the
external origin server 118 are a content server 308 and a content source 304.
_ The administrator of the external origin server 118 determines one or more
client computers 112 authorized for receiving content objects through a
content exchange
116. The routing database 234 is updated by the administrator to allow
individual client
computers 112 to access the content objects through a content exchange 116. A
web page
on the active directory provides an interface to entering information on
client computers
112 into the routing database 234. Other embodiments could automate the
interface
between the external origin server 118 and the routing database 234.
The updates to the routing database 234 are downloaded and stored locally
by client computer 112. Subsequent attempts to access the external origin
server 118 are
redirected to a content exchange 116 to service that request. Redirection in
this way
allows an external origin server 118 to redirect client computers 112 to a
content
exchange 116 without assistance from content manager software.
An external origin server 118 may have one or more content exchanges
116 assigned to carry content objects for the external origin server 118. The
routing
database 234 could redirect subscribing client computers to one or more of
these content
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exchanges 116. If the client computer were allowed to use two or more of these
content
exchanges 116, a client-side routing analysis would be performed on the two or
more
content.exchanges to allow ranking of the relative QOS between them:
The content objects of an external origin server 118 can be preloaded to a
content exchange(s) allocated to provide those content objects. To decrease
latency when
a content object is requested for the first time, the active directory 104 can
crawl the
external origin server 118 to determine the content objects available from
that server 118.
The available content objects may be added to the crawling directory 124. Once
the
available content objects are known, the active directory 104 requests each
content object
from the associated content exchange(s) in order to cause loading of each
content object
on the associated content exchange(s). In this way, content objects are
preloaded on the
associated content exchanges.
With reference to Fig. 4A, a block diagram of an embodiment of a content
exchange portion 116 of the content distribution system 100 is shown. The
content
exchange 116 caches content objects requested by client computers 112 under
the control
of the content manager 312. Included in the content exchange 116 are a
tracking system
402, and a content node 406. The tracking system includes a content tracker
404, a health
check426, status information 420, a local content catalog 416, and an origin
server
database 424 while the content node 406 includes a content controller 408 and
a. content
store 412.
The health check 426 can be either a hardware or software application
which provides operational characteristics of an associated content exchange
116. In an
embodiment, the health check 426 provides a single indication of content
exchange 116
status. The single indication may be a normalized value between zero and one
indicating
a combination of content exchange characteristics including, for example, a
CPU load, a
CPU temperature, a number of concuixent connections, and a number of requests
a
content exchange is facilitating. In an alternate embodiment, the health check
426 could
monitor characteristics of a content exchange 116 while running on another
content
exchange 116, origin server 108 or location.
The content store 412 holds the content objects. available for download to
the client computers 112 from that content exchange 116. The name of the
origin server
108 providing the content object along with path information and the filename
is stored
with the content object in the content store 412. Via the Internet 120, the
client
computers 112 connect to the content store 412 and download the content object
file or
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data stream. As new content objects are added to the content store 412, old
content
objects are removed. The age of a content.object relates to the last time a
content object
was accessed. Some content objects on the store 412 never age such that they
stay in the
store 412 for a predetermined time. An origin server 108 could arrange for the
content
exchange 112 to store a content object for a predetermined period of time.
When the client computer 112 requests a content object from the content
store 412, the content object may not be currently loaded in the content store
412. The
content store 412 notifies the content controller 408 of the unfulfilled
request for the
content object. The content controller 408 locates missing content objects or
portions
thereof in other content exchanges 116 or from the content server 308 that
originated the
content object. The missing content objects are loaded into the content store
412 by the
content controller 408 such that the client computer 112 can download this
information.
When a content object is missing from content store 412, the content
controller 408 first checks with other content exchanges 116 to determine if
the object is
available. If no content exchange 116 has the desired content object, the
content server
308 that originated the information is queried for the content object. The
content store
412 does not include the lP address for the originating content server 308 so
the dynamic
DNS 204 is queried for that information. Given the origin server name, the
dynamic
DNS 204 provides the IP address such that the content controller 408 can
request the
content object from the proper content server 308.
The content tracker 404 reports to the system 100 the current items in the
content store 412 and status information for the content exchange 116. The
local content
catalog 416 records the origin server name, path and filename for each content
object or
portion of a-content object in the content store 412. As new items are added
to and old
items are removed from the content store 412, the local content catalog 416 is
updated.
When a content manager 312 connects to the system 100, a query is made to all
content
trackers 404 to determine what portions of content objects are stored on the
content stores
412. The initial query provides a baseline to which the content tracker 404
updates as
changes are made to the content store 412. The changes are sent directly to
each of the
content managers 312 that has content stored in the content store 412. The
dynamic DNS
204 is used during this process to determine the IP address corresponding to
the origin
server name for each content object.
The content tracker 404 also provides status information for the content
exchange 116 to the content mangers 312. The status information is sent
periodically to
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each of the content managers 312 as a broadcast or multicast, for example,
every five
minutes and/or when changes occur. The .status information could include the
number of
concurrent links to the content exchange currently in use, the total number of
concurrent
links allowed, the bandwidth utilization, and the cache chum rate. In other
embodiments,
' the status information is posted to a central location that the content
manager 312 can
query when determining where to send a client computer 112 for a downloading a
content
object.
The content tracker 404 maintains the origin server database 424 to track
the origin servers 108 active in the system 100. After attaching to the
system, all origin
servers 108 identify themselves to the content trackers 404. The content
trackers 404
record the origin server name and IP address in the origin server database
424. A query
to the dynamic DNS provides the IP address for a given origin server name. If
an origin
server 108 notifies the content tracker 404 of impending unavailability or if
the content
tracker 404 cannot contact a particular origin server, the entry for that
origin server is
removed from the origin server database 424. Additionally, the content
corresponding to
that origin server 108 may be purged from the content store 412 and the local
content.
catalog 416 is updated. In some embodiments, the content object and content
object
portions are not purged, but are simply tagged for deletion as the storage
space is needed.
In some embodiments, the content controller 408 can be instructed by the
system 100 to acquire and retain predetermined content objects in the content
store 412.
Content objects that are anticipated to be wanted can be preloaded in
preparation for the
demand. The desirability of a content object can be determined by monitoring
click-
throughs to those content objects from the search and directory pages 212,
216. For
example, content objects related to a famous person could be loaded onto
content stores
412 immediately before a biography program on the famous person is aired on
network
television. Alternatively, users could subscribe to a service that loads
content objects to
some content exchanges 116. For example, a scheduled network program could be
loaded to coincide with a TV broadcast the user could view over the Internet
120 in lieu
of the TV broadcast. The content would be available without delay to the
subscribed
users.
With reference to Fig. 4B, a block diagram of another embodiment of a
content exchange portion 116 of the content distribution system 100 is shown.
This
embodiment includes multiple content nodes 406 coupled to a single tracking
server 402.
A content bus 428 allows content nodes 406 to check each others content stores
412 for
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missing content objects. The content bus 428 could also couple to other
content notes in
other locations. The content bus 428 may or may not travel in part over the
Internet 120.
Referring next to Fig. 4C, a block diagram of an embodiment of a content
exchange site 432 including multiple content exchange servers 116 is shown.
Even
though the content exchange site 432 includes multiple content exchange
servers 116, it
appears to the system a single content exchange 116. The load of the content
exchange
site 432 is distributed among the content exchange servers 116. A switch 436,
such as a
layer four switch, distributes the content object requests to the content
exchanges 116 and
aggregates the spooled responses to the Internet 120.
Referring next to Fig. 5, a block diagram of an embodiment of a client
computer portion 112 of the content distribution system 100 is shown. The
client
computer 112 communicates to the Internet 120 in order to deliver content to a
user.
Included in the client computer 112 are a viewer object proxy 504, a content
processing
program 508, preference information 512, a network interface 516, and hosted
server
routing 520.
The content processing program 508 is typically software that interprets or
processes a content object downloaded from the Internet 120. Examples of
content
processing programs 508 include web browsers, file transfer protocol (FTP)
software,
gopher software, news (NNTP), mail programs, streaming media players, non-
streaming
media players, and other software. The Internet communication from content
processing
program 508 that is normally sent directly to the Internet is redirected to
the viewer object
proxy 504.
The viewer object proxy 504 serves as intermediary between the Internet
120 and the content processing program 508. After installation of the viewer
object
proxy 504, it determines its general location relative to known points on the
Internet 120.
Content exchanges 116 that are reasonable candidates for providing sufficient
QOS are
tested to determine the number of hops necessary and the latencies between
each content
exchange 116 and the viewer object proxy 504. A weighting of QOS factors, such
as the
number of hops and bandwidth achieved, is recorded as preference information
512 and is
passed as meta-data to the content manager 312 in an HTTP header.
Other embodiments could pass meta-data in any sort of data channel and
not just through a HTTP header. 'For example, the meta-data could travel
through a
dedicated port, an IP address, a URL, a header, or other logical channel.
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The preference information 512 is the result of network analysis performed
from the client computer perspective 112. When a content object is requested,
the
preference information 512 is communicated to the content object manager 312
which in
turn selects an appropriate content exchange 116 for the client computer 112.
Periodically, such as every hour, the preference information 512 is updated
using
automated tests or is updated manually by the user. Subsequent tests take into
account
the previous results to efficiently consider preferred content exchanges. For
example, the
first analysis may check one hundred content exchanges, but a subsequent
analysis could
eliminate the poor performing content exchanges such that only fifty are
analyzed.
The preference information 512 includes a list of content exchanges 116
and their associated QOS values resulting from client-side network analysis.
In some
embodiments, there are multiple pathways to an external origin server 118. The
multiple
pathways are separated by port, IP address, server identification (ID), and/or
other
mechanisms. Client-side network analysis could be used to determine a QOS
value
associated with each pathway to an external origin server 118 or any source of
a content
object with multiple pathways.
After the user of the client computer 112 chooses a content object, the
origin server name is provided to the viewer object proxy 504. The origin
server name is
used for the viewer object proxy 504 to query the dynamic DNS 204 for the IP
address of
the origin server 108. Once theIP address is known, the content processing
program 508
is redirected to the content manager 312 for the desired content object. The
content
manager 312 is passed the preference information 512 to allow routing to the
appropriate
content exchange 116. In this embodiment, the preference information 512
includes the
preferred ten content exchanges, but could be adjusted by the user.
In some embodiments, the viewer object proxy 504 can be HTTP-specific
but protocol independent for routing information. Thus, routing information is
transferred according to HTTP, but the actual routing information is protocol
independent. However, one skilled in the art would recognize that the viewer
object
proxy 504 can also be configured to work with other network protocols
as'needed. For
example, the viewer object proxy 504 can also be configured to operate in
accordance
with FTP, NNTP, RTP, RTSP, SMTP, or SHOUT etc.
The client computer 112 includes a host server routing 520 database. This
host server routing 520 can include information related to external origin
servers 118
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accessible by the client computer 112. In an embodiment, host server routing
520 is a
portion of the routing database 234 included in the active directory 104.
The client computer 112 includes a network interface 516 that connects the
viewer object proxy 504 to the Internet 120. Common examples of network
interfaces
516 include analog modems, DSL modems, ISDN, cable modems, satellite modems,
cellular modems, etc.
In this embodiment, the client computer is associated with a home user. In
other embodiments, the client computer could serve digital movies to a theater
or provide
content objects to a corporate network user, a hotel patron or apartment
complex.
With reference to Fig. 6, a block diagram of an embodiment of a content
distribution system 600 is shown. This figure depicts data flow between data
blocks
without showing transport over the Internet 120. It is to be understood,
however, that the
Internet 120 is used in some embodiments. Also, the figure is somewhat
simplified in
that some blocks from Figs. 2-5 and the external origin server(s) 118 and
crawling
directory 124 are not included to simplify the Fig. 6.
The network interface 516 is the connection to the Internet 120 for the
client computer 112. The client computer 112 connects to the directory and
search pages
212, 216 to allow the user to select content objects for download. When a
content object
is selected, redirection of the client computer 112 from the active directory
104 to the
appropriate origin server 108 uses the dynamic DNS 204. Preference information
512 is
passed to the content manager 312 to assist its selection of the source for
the content
object. Depending on the selection made by the content manager 312, the
content object
is downloaded from one of the content exchanges 116 or from the content server
308.
The active directory 104 interacts with the other modules in the system
600. The client computer 112 accesses the directory and search pages 212, 216
to select a
content object. The content tracker 404 and content manager 312 respectively.
provide
status and catalog information to the server manager 208. Account information
is
provided to the server manager 208 by the administrator of the origin server
108 and by
the user of client computer 112 to maintain the subscriber database 224.
Redirection
from the origin server name to the IP address of the origin server 108 is
provided to the
viewer object proxy 504, the content tracker 404 and the content controller
408 by the
dynamic DNS 204.
The origin server 108 communicates with the server manager 208, the
client computer 112, the content tracker 404, the content store 412, and the
content
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controller 408. The local content catalog 316 is provided to the server
manager 208 from
the content manager 312 in order to maintain the server database 228 with
current content
information. Preference information 512 is provided to the content manager 312
from the
client computer 112 to facilitate selection of a source of the content object.
The content
tracker 404 interacts with the content manager 312 to know what content
objects are
stored on the content exchange 116. Content objects are read from the content
server 308
by either the content store 412 or the client computer 112.
The content exchanges 116 interact with the other modules in the system
600 as well. Status information is provided to the active directory 104 and/or
the content
manager 312. The dynamic DNS is used by both the content controller 408 and
the
content tracker 404 to find the IP address of an origin server 108 that
contains a content
object. A selected content exchange may contact other content exchanges when
an object
is needed for the content store 412. If the other content exchanges do not
have the
content object, the content controller 408 requests the object from the
content server 308
for delivery to the selected content store 412.
Referring next to Figs.-'7A-B a flow diagram of an embodiment of a
process for distributing content to a user is shown. Before the depicted
process, the user
and administrator respectively download and install software for the client
computer 112
and origin server 108. The administrator chooses content on the content server
for
publishing to the system 600. To determine the preference information 512, the
viewer
object proxy 504 automatically interrogates nearby content exchanges 116 for
adequate
QOS.
The depicted process begins in step 704 where the user directs a web
browsing content processing program 508 to the directory or search page 212,
216 of the
active directory 104. In this embodiment, the user queries a search engine on
the search
page 216 using a boolean query in step 708 to find a content object. The
search engine
would search the server database 228 for hits and may also search a crawling
directory
124 in step 712. Alternatively, the user could navigate the directory page 212
to find a
desired content object.
The search or directory page 212, 216 presents links for each of the
content objects that the user might select in step 716. Each link includes the
origin server
name 108, port, path and name for the content object. Given the choices
available, the
user may select one of the links corresponding to the desired content object
in step 720.
The dynamic DNS 204 is queried by the viewer object proxy 504 to determine the
IP
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address of the origin server name from the link. Once the IP address is known,
the
content processing program is redirected to the IP address retrieved from the
dynamic
DNS 204 and the path and filename from the link.
Once the client computer 112 is connected to the content manager 312, the
preference information 512 is forwarded to the content manager 312 in step
724. The
content manager 312 analyzes the content location database 320, the preference
information 512 and the status information to determine the source of the
content object
to redirect the client computer 112 to in steps 728 and 732.
A determination is made in step 736 as to whether the source is a content
exchange 116 or the content server 308. The content server 308 maybe chosen if
the
content manger 312 determines it can provide adequate QOS or superior QOS. In
some
embodiments, the content server 308 is only considered as a source if there
are no content
exchanges 116 that can provide adequate QOS. If the content server 308 is
chosen, the
origin server 108 provides the content object to the client computer 112 in
step 740.
If the content manager 312 selects a content exchange 116 to host the
content object request, the content processing program 508 is redirected to
the chosen
content store 412 and processing continues in step 744 of Fig. 7B. The content
processing program 508 requests the content object in the link from the
content store 412
in step 744. If the whole content object is in the content store 412, the
object is
downloaded from that content store 412 to the client computer in steps 748 and
752.
Alternatively, a whole copy of the content object is assembled in the
content store 412 if any portion of the content object is missing. The
building of the
whole content object happens transparently to the user. In steps 756 and 760,
the content
controller 408 queries the other content exchanges 116 to determine which have
the
missing portion of the content object. The content object is reassembled in
the content
store 412 from beginning to end such that the beginning is available as soon
as possible
for download by the client computer 112.
In an iterative manner, the missing portions are retrieved from each
content exchange 116 in step 764 until the whole content object is in the
content store
412. If no other content exchange 116 has the missing portion of the content
object, a
query is made to the origin server 108 for the missing portion, in step 768.
The dynamic
DNS 204 is queried to determine the IP address of the origin server name for
the content
object. The content controller 408 is directed to the origin server 108 with
the content
object in step 772 by the dynamic DNS 204. The missing portion is downloaded
from the
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content server 308 of that origin server 108 in step 776. Processing loops
back to step
748 to retrieve any other missing portions..
This process of searching for portions continues in an interative manner
until all missing portions are copied to the content store 412. Although this
embodiment
sequentially retrieves the missing portions, other embodiments could determine
the
location of the missing portions and retrieve them in parallel, in any order
or in the order
found.
Referring now to Fig. 8, a block diagram of an embodiment of the viewer
object proxy 504 is shown. The viewer object proxy 504 includes the following
functions: a path evaluator 850, a weighting function 852, a display function
or routine
854, a look ahead logic function 856, a standard web access function 858, a
decompression function 860, a decryption function 862, an electronic commerce
function
866, a security function 864, and a main function 868 which interfaces the
various other
functions in the viewer object proxy 504. It should be recognized that the
preceding list
of possible functions included in the viewer object proxy 504 is merely
illustrative and
that one skilled in the art would recognize other functions relevant to the
viewer object
proxy 504.
Because the viewer object proxy 504 is a proxy with all viewer requested
content objects flowing through it, a look ahead logic function 856 can be
implemented.
In an embodiment, the look ahead logic function 856 anticipates the user's
next browse or
move and fetches the related browse information for storage on the client
computer 112
before an actual request by the user. The pre-fetched information is retained
until the
information is actually requested by the user. If the look ahead logic
function 856
incorrectly anticipates the user's next browse, the pre-fetched data is
discarded. As an
example, the look ahead logic function 856 performs a pre-fetch of a commonly
accessed
page lower in the hierarchy of the directory page 212 (as described with
reference to Fig.
2). By pre-fetching information, the look ahead logic function 856 is able to
reduce
access latency.
In some embodiments, the decompression function 860 and the decryption
function 862 are provided. These functions 860, 862 provide capability to
decompress
and decrypt information received from either an origin server 108, a content
exchange
116, an external origin server 118, or any other server on the Internet 120.
For any user request, the viewer object proxy 504, based on availability of
the decompression 860 and decryption 862 functions, can negotiate the form of
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compression and encryption that will be used during a content object transfer
with a
server on the Internet 120. Thus, anytime a user is surfing the Internet 120,
the viewer
object proxy 504 tells any contacted server what compression and encryption
are
supported. This does not require contacted servers to have special software,
but QOS can
be increased where a contacted server supports the same compression,
encryption and
security functions supported by the viewer object proxy 504. It should be
recognized that
many communication mechanisms can be used to decompress and decrypt. For
example,
FTP, NNTP, RTP, RTSP, or SMTP could be used.
In an embodiment, decryption and decompression negotiation is
accomplished by way of HTTP. More specifically, the negotiation is achieved
via an
extended HTTP header.
Further, in some embodiments, it is possible for the user to disable either
or both the decompression function 860 and the decryption function 862. If the
respective functions 860, 862 are disabled by the user, the viewer object
proxy 504 will
not negotiate for use of the disabled function.
In some embodiments, the viewer object proxy 504 includes the security
function 864. The security function 864 operates to permit or deny access when
appropriate. More specifically, the security function 864 provides control
such that
content objects will be decrypted only if authority is given by a trusted
system. For
example, a trusted system may only provide authority to accept and/or decrypt
data where
a specific dongle type hardware device is attached to the client computer 112
and the
attachment condition is reported by the security function 864 via the viewer
object proxy
504.
In some embodiments, the viewer object proxy 504 includes the electronic
commerce function 866. The electronic commerce function 866 can be integrated
tightly
with an electronic commerce engine resident on the Internet 120. By way of the
electronic commerce function 866, users are provided a mechanism for
purchasing
content objects. For example, token credits stored in the subscriber database
224 could be
credited to origin servers 108 to download content objects.
In addition, the viewer object proxy 504 can include the standard web
access function 858 which provides access to Internet domains residing outside
of the
content distribution system 100. In an embodiment, when the viewer object
proxy 504
receives a user request from the content processing program 508 for a content
object
sourced by a domain outside the content distribution system 100, the standard
web access
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function 858 determines if the content object was previously saved on the
client computer
112. If the requested content object was previously saved, the saved content
object is
returned by the standard web access function 858 to satisfy the user request.
If the
requested content object was not previously saved, the user request is passed
on by the
standard web access function 858 and the content object is retrieved as if the
content
processing program 508 had accessed the Internet 120 directly.
The path evaluator 850, weighting function 852 and display function or
routine 854 are described in relation to a flow diagram of a viewer object
proxy
background application 900 included as Fig. 9. The background application 900
utilizes
various viewer object proxy 504 functions to determine desirable content
exchanges 116
capable of providing sufficient QOS to the client computer 112. The desirable
content
exchanges 116 are stored in memory as preference information 512 and
subsequently
communicated to the content object manager 312.
Referring to Fig. 9, a setup 982 is performed at startup 980 and the display
routine 854 is launched. The setup 982 can include requesting and initializing
graphics
memory in the client computer 112, initializing a proxy, and launching the
display routine
854. Further, setup 982 may include any processes for initializing a graphics
display or a
proxy.
Following setup 982, an information request and receive 984 is performed.
During information request and receive 984, the content exchange database 232
from the
active directory 104 is downloaded to the client computer 112. As mentioned
above,
content exchange databases 232 can be regionalized or partitioned by a variety
of
methods including, but not limited to, improved QOS criteria or subscription
services
criteria. Thus, in some embodiments, information request and receive 984
results in
retrieval of a content exchange database 232 containing only content exchanges
116
.geographically proximate to client computer 112. As an example, a retrieved
content
exchange database 232 may include only content exchanges 116 located in North
America. In other embodiments, information request and receive 984 results in
retrieval
of a content exchange database 232 containing only content exchanges 116 which
support
a particular subscription service or which are attributed to a particular
provider.
Alternatively, the content exchange database 232 could be limited to content
exchanges
that are attributed to a particular Internet Service Provider, or that support
a particular
protocol, or even that provide content objects in a particular language. In
yet other
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embodiments, information request and receive 984 results in retrieval of a
content
exchange database 232 containing all possible content exchanges 116.
In some embodiments, information request and receive 984 further
includes requesting and receiving some portion of the routing database 234
which
includes routing information for external origin servers 118. The received
portion of
routing database 234 is stored to memory in the client computer 112 as hosted
server
routing 520.
Among other uses, information provided through information request and
receive 984 can be used to generate a display for the user. For example, in
some
embodiments, the location coordinates and icon information provided as part of
the
content exchange database 232 can be used as part of a graphical presentation
provided to
the user via the display function or routine 854. The graphical presentation
could show
the user what is available on the content distribution system 100 or elsewhere
on the
Internet 120. Further, the graphical presentation could show various paths
from the client
computer 112 to multiple content exchanges 116. In a particular embodiment,
physical
locations of content exchanges 116 and origin servers 108 are superimposed on
a world
map which is displayed to the user.
Beyond using the content exchange database 232 by the display function
854, information from the content exchange database 232 can be used to perform
a path
QOS evaluation 986. More specifically, QOS for paths between the client
computer 112
and each content exchange 116 or node specified in the content exchange
database 232
can be determined and stored in memory in the client computer 112.
It should be recognized that receiving a list of content exchanges 116
through information request and receive 984 is illustrative of a method for
determining
potential content exchanges 116. In alternative embodiments, one could obtain
a list of
possible content object sources, such as content exchanges 116, external
origin servers
118 and origin servers 108, or by using a list compiled by the viewer object
proxy 504.
The list could be based on knowledge of the viewer object proxy 504 obtained
during
earlier content object transfers inside or outside of the content distribution
system 100.
In an embodiment, the path QOS evaluation 986 is performed for paths
associated with all content exchanges 116 listed in the content exchange
database 232.
To start, a path associated with the first content exchange 116 listed in the
content
exchange database 232 is analyzed. Next, in step 988, a determination is made
if another
content exchange 116 is provided in the content exchange database 232. If
another
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content exchange 116 is provided, the path to the content exchange 116 is
evaluated.
This process continues until the path' QOS' evaluation 986 is performed for
all content
exchanges 116 listed in the content exchange database 232. It should be
recognized that
path QOS evaluation could be performed on any content object source or
transfer node
and is not necessarily limited to evaluating content exchanges 116 and origin
servers 108.
It should be understood that a transfer node can be a content exchange 116 or
other server
capable of storing and transferring content objects. It should be recognized
that as it is
used, in relation to path QOS evaluation, the term path incorporates routing.
In other embodiments, only a subset of the content exchanges 116 listed in
the content exchange database 232 are evaluated. Evaluating only a subset of
content
exchanges 116 from the content exchange database 232 provides more efficient
path QOS
evaluation 986. This increased efficiency can be achieved where it is known
that certain
content exchanges 116 are unlikely to provide sufficient QOS and are thus not
worth
evaluating. Thus, for example, where the client computer 112 is in North
America and it
is perceived that content exchanges outside North America are unlikely to
provide
sufficient QOS, path QOS evaluation 986 is only performed for content
exchanges 116
located in North America.
Alternatively, a site based path QOS evaluation 986 can be performed
where it is perceived that different types of content exchanges 116 are likely
to provide
similar service. More specifically, one content exchange 116 associated with
each
content exchange site 432 represented in the content exchange database 232 is
evaluated.
From this, it can be determined which content exchange sites 432 are likely to
provide
sufficient QOS. Subsequently, content exchanges 116 associated with the
content
exchange sites 432 determined likely to provide sufficient QOS are each
individually
analyzed. In this way, content exchanges 116 associated with content exchange
sites 432
unlikely to provide QOS are not evaluated.
In another embodiment, the path QOS evaluation 986 only for content
exchanges 116 that support particular protocols. Or, alternatively, path QOS
evaluation
986 may only be performed for content exchanges 116 at a content exchange site
432
where a particular protocol is supported by at least one content exchange 116
at the site
432.
Further, in some embodiments, path QOS evaluation 986 is performed
only once for a particular content exchange 116. Thus, where a particular
content
exchange 116 has multiple IP addresses, ports or names, path QOS evaluation
986 is only
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performed for one IP address, port or name. This eliminates redundant
evaluation during
path QOS evaluation 986. However; it should be recognized that path QOS
evaluation
986 could be performed for multiple IP addresses, ports or names for the same
content
exchange 116 where it is perceived that a different QOS is possible.
Selecting which subset of content exchanges 116 in the content exchange
database 232 to evaluate can be based on a criteria supplied by the client
computer 112
and based on client computer experience, by the active directory 104, by a
content
exchange 116, origin server 108, and/or a user.
In an embodiment, path QOS evaluation 986 is accomplished using a
combination of network analysis methodologies including, but not limited to,
traceroute,
bandwidth test via file transfer, server health check, server load/resource
check, ping, path
difference, Border Gate Protocol (BGP) routing information, and port response
time.
Traceroute includes any analysis which returns a route that packets take
between a particular content exchange 116 and the client computer 112.
Typically,
traceroute returns the number of hops traversed, the IP addresses of traversed
hops, and
the time required by a traverse between the client computer 112 and the
content exchange
116.
Bandwidth test via file transfer includes any analysis where a bulk
information transfer is performed between the content exchange 116 and the
client
computer 112. During the bulk transfer, various indices of performance are
derived
including, but not limited to, the time required to perform the bulk transfer.
Typically,
data transferred between the content exchange 116 and the client computer 112
is highly
random. The random nature of the data reduces the impact of any compression
occurring
between the client computer 112 and the content exchange 116.
Ping includes any analysis where information is sent by the client
computer 112 to a particular content exchange 116 and the client computer 112
awaits a
response from the content exchange 116. Typically, ping is performed via UDP
or any
other lossy protocol (i.e. a protocol which does not guarantee a response).
Ping is useful
to verify whether the content exchange is operational. Alternatively, the time
required to
receive the reply can be used as an indication of QOS.
Server health check and server load/resource check can include any
analysis which determines various heuristics related to the health, loading
and available
resources of a content exchange 116, origin server 108, or other transfer
node. In general,
a content exchange 116 is queried to determine various operating
characteristics
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including, but not limited to: an average and peak CPU load, -a CPU
temperature, a
number of pages transferred betweeir the hard drive and RAM to resolve cache
misses, a
rate at which the content exchange 116 ,is issuing read and write operations
to the hard
drive, a number of requests the content exchange 116 is currently servicing,
an average
'number of users accessing the content exchange, a number of concurrent
connections, a
rate of inputs and outputs to/from the content exchange 116, an average size
of a content
object requested from the content exchange 116, a size of a local memory,
including
RAM and hard drive memory, associated with the content exchange 116, an
average
content object size included in the local memory, a number of content objects
included in
the local memory, an average time a content object remains in the local
memory, a rate of
instances a content object is'not found in the local memory, and any other
error
indications and/or status information.
The aforementioned heuristics can be determined using the health check
330, 426 associated with a particular content exchange 116 or origin server
108. In an
embodiment, health check 330,426 are software applications running on a
content
exchange 116 and origin server 108 respectively. When queried by the viewer
object
proxy 504, the health check 330,426 may provide a CPU load, a CPU temperature,
a
number of concurrent connections, and a number of requests the content
exchange 116 or
origin server 108 is currently servicing. In some embodiments, viewer object
proxy 504
queries the content object exchange 116 via HTTP to retrieve server health
check
heuristics. It should be noted, however, that one skilled in the art would
recognize many
mechanisms for accessing server health heuristics including, but not limited
to, FTP,
NNTP, RTP, RTSP, SHOUT, SMTP, or connecting to the node through a designated
Port.
In other-embodiments, a request for status by the viewer object proxy 504
to the health check 330, 426 results in a single status indicia being
returned. The single
status indicia is between one and zero with one indicating poor
characteristics and zero
indicating good characteristics. Good and poor characteristics are determined
based on
the ability or capability for a content exchange 116 or other transfer node to
act as a
content object cache. Thus, in an embodiment, an indicia of 0.9 indicates an
inability to
maintain a content object local to a content exchange 116 for an extended
time.
Alternatively, an indicia of 0.2 indicates an ability to maintain a content
object for an
extended time.
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To determine the single status indicia, many machine characteristics can
be monitored and combined. In an embodiment, the single status indicia
includes the
following characteristics in combination: an average CPU load, a size of a
local memory
associated with the content exchange 116, an average content object size
included in the
local memory, and an average time a content object stays in the local memory.
The
combination of these individual characteristics serve to rate the ability of
the content
exchange to act as a content object cache. To combine the characteristics into
a single
indicia, each of the characteristics is first normalized to a percentage of a
predetermined
use level. The normalizing is performed such that 100% indicates the best
possible
characteristic value and zero indicates the worst characteristic value. Then
the
normalized values are multiplied by a predetermined percentage of the overall
status
indicia and the multiplied values are aggregated to create a single indicia
between one and
0. It should be recognized that a number of alternative sets of
characteristics can be used
to form a single indicia. For example, an embodiment could combine an average
CPU
load, a CPU temperature, an average number of users connected to the source,
and a rate
of inputs and outputs to/from a content exchange to form the single indicia.
The following provides an example of forming the single indicia where: a
CPU load of 90% of maximum, an average size of a content object normalized to
20%, a
size of a local memory normalized to 30%, included in the local memory, an
average
content object size included in the local memory normalized to 80%, and an
average time
a content object stays in the local memory normalized to 50% are found. These
normalized values can be aggregated such that each of the characteristics
plays an equal
role in the single indicia. Thus, each of the normalized values are multiplied
by 20% and
subsequently aggregated to create the single indicia. Accordingly, the single
indicia in
the example is 54% or 0.54. It should be recognized that the example and
embodiment
are merely illustrative and that a number of alternative methods for combining
multiple
characteristics into a single indicia are possible.
BGP routing information includes any information returned as a result of a
Border Group Protocol analysis. In general, this information is related to
path topology
and includes, but is not limited to an Autonomous System (AS) Path Attribute,
and AS
Next Hop.
Path difference includes any analysis which determines a bandwidth or
latency difference between alternative paths connecting the content exchange
116 and the
client computer 112.
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Port response time includes any analysis which provides an indication of
port response. In general, the test provides information related to the
response time of a
content exchange 116 port. For example, port time can include any analysis
where the
time required to transfer a zero length message is determined. Typically, the
result of a
zero length transfer is reported as the number of exchange messages per
second. The
number of exchanges per second can be used to infer content exchange 116
latency.
It should be recognized that any of the aforementioned methodologies may
be combined to provide an indicator of QOS or transmission quality for a path
connecting
a content exchange 116 and the client computer 112. Alternatively, any of the
aforementioned methodologies may be combined with other network analysis
methodologies to provide QOS evaluation 986. For example, in an embodiment,
ping,
traceroute and health check are used in combination to provide a QOS
evaluation.
In another embodiment, all of the aforementioned methodologies are
combined to determine QOS. To determine QOS, each of the methodologies is
performed and a QOS factor for each methodology is returned. The QOS factors
from
each of the methodologies are then normalized and aggregated to form a single
QOS
factor for each analyzed path. Normalizing the QOS factors can be done by
equally
weighting each of the methodologies.
For example, in an embodiment, the following normalizing and
aggregation occurs where: (1) traceroute returns 9 hops, (2) bandwidth test
via file
transfer returns 300 msec, (3) server health check returns a one for healthy,
(4) server
load/resource check returns 65% average CPU load, (5) BGP routing information
returns
four hops' 'and (6) port response time returns 45 msec. Also, each of the
returned values
is compared to a respective predetermined maximum value such as: (1) thirty
hops for
traceroute, (2) 500 msec for bandwidth test via file transfer, (3) one for
server health
check, (4) 100% for server load/resource check, (5) six hops for B GP routing
information,
and (6) 100 msec for port response time.
To normalize and aggregate, each of the returned values are divided by
their respective predetermined maximum. Thus, traceroute yields 0.33,
bandwidth test
via file transfer yields 0.6, server health check yields 1, server
load/resource check yields
0.65, BGP routing information yields 0.75,,and port response time yields 0.45.
Next all
of the normalized values are aggregated to provide 3.78 as an overall QOS
factor. This
QOS factor is then used to compare between various content exchanges 116.
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In other embodiments, values returned from each of the methodologies are
disparately weighted prior to aggregation., Weighting factors can be provided
by a user to
affect the QOS factor returned. Such an embodiment is described using the
values from
the previous illustration where the normalized values returned from the
various
methodologies are: (1) 0.33 for traceroute, (2) 0.6 for bandwidth test via
file transfer, (3)
one for server health check, (4) 0.65 for server load/resource check, (5) 0.75
for BGP
routing information, and (6) 0.45 for port response time. Continuing the
illustration the
following weighting factors are used: one for traceroute, three for bandwidth
via file
transfer, one for server health check, four for server load/resource check,
one for BGP
routing information, and three for port response time are used. Each of the
normalized
values are multiplied by their respective weighting factor to yield: (1) 0.33
for traceroute,
(2) 1.8 for bandwidth test via file transfer, (3) one for server health check,
(4) 2.6 for
server load/resource check, (5) 0.75 for BGP routing information, and (6) 1.35
for port
response time. Next, the weighted normalized values are aggregated to provide
7.83 as
an overall QOS factor. Again, this QOS factor is used to compare between
various
content exchanges 116.
In addition to providing the weighting factors, the user can manually select
a preset order of content exchanges 116, or provide only a single acceptable
content
exchange 116 either of which effectively overrides the automated analysis of
path QOS
evaluation 986. Thus, a user can achieve any desired result by either allowing
fully
automated generation of QOS factors for content exchanges 116, by manually
weighting
the path QOS evaluation 986 to effect QOS factors returned for content
exchanges 116, or
by overriding the automatic analysis and providing a list of desired content
exchanges
116.
In some embodiments, a multi-tiered path QOS evaluation 986 can be
performed by using a subset of the aforementioned methodologies to perform a
coarse
QOS analysis followed by a fine QOS analysis on a limited number of content
exchanges
116. This multi-tiered analysis increases efficiency of path QOS evaluation
986 by
avoiding fine QOS analysis of content exchanges unlikely to provide sufficient
QOS.
Accordingly, in an exemplary embodiment, both ping and traceroute are applied
to
perform coarse QOS analysis for all content exchanges 116 included in content
exchange
database 232. Subsequently, a pre-determined number of content exchanges 116,
preferably less than twenty-five, which provide sufficient QOS according to
coarse QOS
are evaluated using server health check as the fine QOS analysis. Results of
the fine QOS
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analysis define the content exchanges 116 which provide sufficient QOS. It
should be
recognized that any combination of methodologies can be applied to perform
either fine
or coarse QOS analysis. Alternatively, it should be recognized that either
fine or coarse
QOS analysis can themselves involve multi-tiered analysis.
After path QOS evaluation 986 is performed for potential paths and a QOS
factor for each evaluated path is stored in memory of the client computer 112,
the content
exchanges 116 associated with the evaluated paths are prioritized 990. Content
exchanges 116 are prioritized based upon the QOS factor determined in path QOS
evaluation 986. Based on the QOS factor, a predetermined number of content
exchanges
are chosen, ranked and stored as preference information 512. In an embodiment,
the
preference information 512 includes the preferred ten content exchanges 116.
As disclosed above, in alternative embodiments, one could perform path
QOS evaluation on any content object source, not necessarily just content
exchanges 116
and origin servers 108. In this case, the preference information 512 could
include content
object sources, origin servers 108, as well as content exchanges 116.
Preference information 512 includes a list of content exchanges 116 which
provide sufficient QOS as determined by network analysis performed from the
client
computer's 112 perspective. By analyzing QOS from the client computer's 112
perspective, QOS can be improved.
In some embodiments, preference information 512 is used to form a subset
of content exchanges 116 to be analyzed by path QOS evaluation 986. For
example,
content exchanges 116 may be tested that exist at the same site or are
associated with the
same provider as content exchanges 116 included in the preference information
512.
Thus, only content exchanges 116 that are most likely to provide sufficient
QOS are re-
evaluated in subsequent path QOS evaluation 986. Alternatively, content
exchanges 116
included in the preference information 512 can be analyzed by path QOS
evaluation 986
along with other content exchanges 116 that have been added to the content
exchange
database 232 since the last creation of the preference information 512. In
these ways,
experience of the viewer object proxy 504 can be used to effectuate a more
efficient path
QOS evaluation 986. It should be recognized that the preceding embodiments are
merely
illustrative and that many algorithms exist for selecting content exchanges
116 to increase
efficiency of path QOS evaluation 986. For example, prior operation of path
QOS
evaluation 986 may have returned sufficiently poor results for a particular
content
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exchange 116, that it is never again analyzed, but rather presumptively
rejected. In some
embodiments, this presumptive rejection can be manually overridden by the
user.
Results of path QOS evaluation 986 can be displayed 992 for the user. In
some embodiments, the results are displayed both to entice a user to keep the
viewer
object proxy 504 application running on the desktop of the client computer 112
and to aid
the user in modifying the weighting function 852 to manually control content
exchange
116 selection. In an embodiment, the display function 854 provides, among
other things,
a regional map illustrating hops between the client computer 112 and a
selected content
exchange 116 along with statistics describing operating characteristics.
In addition to updating preference information 512 at startup 980, the
preference information 512 can be updated either at the users request 994 or
based upon a
time interval 996. In an embodiment, preference information 512 is updated at
time
interval 996, which is set at 3600 seconds.
In addition to the background application described in relation to Fig. 9,
the viewer object proxy 504 can provide foreground operations including, but
not limited
to, servicing user requests for content objects from the content distribution
system 100,
the external origin servers 118, and the Internet 120 along with servicing
electronic
commerce requests. More specifically, the viewer object proxy 504 can handle
electronic
commerce requests as previously described in relation to the electronic
commerce
function 866.
Accessing content objects from the content distribution system 100,
external origin servers 118 and the Internet 120 are described in relation to
a flow
diagram of an embodiment of a viewer object proxy request servicing 1000
included as
Fig. 10. Referring to Fig. 10, a the user request 1010 for a content object is
received by
the viewer object proxy 504. In an embodiment, the content distribution system
100 is
accessed through the content processing program 508. More specifically, the
content
processing program 508, in reaction to a user command, issues a request for a
content
object. The request for a content object is passed to the viewer object proxy
504 as the
user request 1010.
Upon receiving the user request 1010, viewer object proxy 504 determines
if the received the user request 1010 can be fulfilled by content distribution
system access
1020. In an embodiment, this determination is done by comparing a source
location of
the user request 1010 with a known list of source locations associated with
the content
distribution system 100. If the source location of the user request 1010
matches a source
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location associated with the content distribution system 100, the request can
be fulfilled
by content distribution system access 1020. Accordingly, content distribution
system
service 1030 is performed to fulfill the user request 1010.
In some embodiments, the viewer object proxy 504 performs content
distribution system service 1030 by communicating the preference information
512 to an
origin server 108. Using the preference information 512, the origin server 108
selects a
content exchange 116 or origin server 108 that can provide sufficient QOS for
the user
request 1010. The origin server 108 then communicates the address of the
selected
content exchange 116 or origin server 108 to the viewer object proxy 504. In
an
embodiment the origin server 108 dynamically writes HTML to provide viewer
object
proxy 504 with the address of the selected content exchange 116 or origin
server 108.
Next the viewer object proxy 504 negotiates compatible compression, encryption
and
security with the selected content exchange 116 or origin server 108. In an
alternate
embodiment, the viewer object proxy.504 could itself select the content
exchange 116 to
provide a requested content object by using the preference information 512.
The viewer object proxy 504 fulfills the user request 1010 by requesting
content objects from the selected content exchange 116 or origin server 108.
As the
requested content object is received, decompression, decryption and security
are provided
by the viewer object proxy 504 according to the negotiated format. Thus, by
passing
client computer 112 specific information to the origin server 108, the origin
server 108 is
able to select a content exchange 116 capable of providing sufficient QOS. By
providing
analysis and content exchange selection from the client computer 112
perspective, more
accurate QOS analysis is achieved resulting in better QOS.
If the user request 1010 cannot be fulfilled by content distribution system
.25 access 1020, the viewer object proxy 504 next determines if the user
request 1010 can be
fulfilled by external origin server access 1040. In an embodiment, this
determination is
done by comparing a domain name indicated in the user request 1010 with domain
names
for external origin servers 118 provided in hosted server routing 520. If the
domain name
indicated in the user request 1010 matches a domain name of an external origin
server
118, the user request 1010 can be fulfilled from the matched external origin
server 118 by
performing external origin server service 1050. Accordingly, external origin
server
service 1050 is performed to fulfill the user request 1010. In other
embodiments, the user
request 1010 may include a directory name, a machine name, an IP address, or
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identifier which is compared with a corresponding identifier for external
origin servers
included in hosted server routing 520.
In an embodiment, the viewer object proxy 504 performs external origin
server service 1050 by accessing a content exchange 116 known to provide
content
objects sourced from the matched external origin server 118. Thus, the viewer
object
proxy 504 redirects the user request 1010 from the matched external origin
server 118 to
the content exchange 116. This redirection is transparent to both the matched
external
origin server 118 and to the content processing program 508. In some
embodiments, the
viewer object proxy 504 negotiates compatible compression, encryption and
security with
the selected content exchange 116. In turn, the content exchange 116 fulfills
the user
request 1010 according to the negotiated compression, encryption and security.
In
instances where the content exchange 116 does not have the requested content
object, the
content exchange 116 requests the desired content object from the matched
external
origin server 118. In either case, the requested content object is provided to
the client
computer 112 by the content exchange 116. As the requested content object is
received,
decompression, decryption and security are provided by the viewer object proxy
504
according to the negotiated format. Thus, by servicing user requests 1010 from
content
exchange 116, a content object provider maintaining an external origin server
118 is not
burdened with distributing content objects.
In an alternate embodiment, the viewer object proxy 504 could perform
external origin server service 1050 by communicating preference information
512 to an
origin server 108. Using the preference information 512, the origin server 108
selects a
content exchange 116 or an origin server 108 that can provide sufficient QOS
for the user
request 1010. The origin server 108 communicates an address to the selected
content
exchange 116 or origin server 108 to the viewer object proxy 504.
The viewer object proxy 504 then fulfills the user request 1010.by
requesting content objects from the selected content exchange 116 or origin
server 108.
The selected content exchange 116 or origin server 108 requests the desired
content
object from the matched external origin server 118 and subsequently fulfills
the user
request 1010 by providing the requested content object to the viewer object
proxy 504.
Thus, by providing for service tailored to client computer 112 better QOS is
achieved. In
addition, by servicing user requests 1010 from a content exchange 116, a
content object
provider maintaining an external origin server 118 is not burdened with
distributing
content objects.
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If the user request 1010 cannot be fulfilled by external origin server access
1040 or content distribution system access 1020, then the user request 1010 is
passed
through to the Internet 120. In an embodiment, the user request 1010 passed
through
1060 to the Internet 120 is handled as described in relation to the standard
web access
function 858.
Referring to Fig. 11, an embodiment of a method for tracking content
between an origin server 108 and a content exchange 116 is shown. Even though
this
figure primarily shows interaction between a single origin server and a single
content
exchange, it is to be understood that each origin server contacts many content
exchanges
and each content exchange contacts many origin servers. The interaction
between all the
origin servers 108 and all the content exchanges 116 allows the system 600 to
track
content object portions.
The process begins with the content exchange and the origin server in an
off-line or unavailable state. In step 1104, the content exchange 116 becomes
available
after beginning operation. When first becoming available, the content exchange
116 is
empty and waits for client computers 112 to request content. As requests by
client
computers 112 are fulfilled, the content store 412 fills itself with content
objects or
portions of content objects.
In step 1108, the origin server 108 of this embodiment begins operation
and becomes available. The origin server 108 publishes its local content
catalog to the
active directory 104 and identifies itself to all content trackers 404 in the
system 600. A
content exchange database 232 of operating content exchanges 116 is available
for
querying such that the content manager 312 knows the addresses of the content
trackers
404.
Each content exchange 116 maintains an origin server database 424 of the
origin servers 108 that have contacted it. Before an origin server 108 goes
offline, the
origin server 108 will attempt to contact all content exchanges 116 to notify
them 116 of
this change in status. Offline origin servers 108 are removed from the origin
server
database 424. Whenever an origin server 108 fails to respond to the content
exchange
116 sending status, that origin server 108 is presumed offline and is removed
from the
origin server database 424.
Whenever a content exchange 116 is about to go offline, it attempts to
notify the system 600. The origin servers 108 that have content objects or
portions of
content objects are notified such that the content exchange information 324
and the
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content location database 320 in each origin server 108 can remain current.
Additionally,
the active directory 104 is notified so the content exchange database 232 will
accurately
reflect the content exchanges 116 available to the system 600.
Each content tracker 404 that is contacted in step 1108, responds to the
content manager 312 with status information 420 and any content objects
associated with
that content manager 312 in step 1112. Since the content manager 312 is just
coming
online, it is unlikely there are any content objects on the content store 412
that originated
from the content server 308 associated with that content manager 312. The
status
information 420 from each content exchange 116 that responds is stored by the
content
manager 312 as content exchange information 324. In various embodiments, the
status
information 420 may be reported with or without content catalog information
416. When
routing a client computer 112 to a source for a content object, the content
exchange
information 324 is used to determine the loading for the content exchanges
under
consideration. Periodically, each content tracker 400 updates all active
content managers
312 with status information such that,the content exchange information 324 is
current.
Alternative embodiment content trackers 404 could provide updated status
information
420 when significant changes in status occur rather than periodically.
In step 1116, the content manager 312 sends a client computer 112 to the
content exchange 116 to fulfill a request for a content object. Before
redirecting the client
computer 112, the content manager 312 makes a determination that a particular
content
exchange is the preferred source for that content object. If the whole content
object is not
present on the preferred content exchange 116, the content controller 408
retrieves the
missing content object portions in step 1120. The client computer 112 begins
downloading the content object once the beginning of the content object is
available from
the content exchange 116.
At a predetermined interval or when changes occur, the content tracker
404 reports to all content managers 312 the content objects and/or content
object portions
that are stored in the content store 412. The local content catalog 416 stores
a list of the
content object and/or content object portions retained in the content store
412. In step
1124, the content object possibly added in step 1120 is reported back to the
origin server
108 that originally provided the content object. Each origin server 108 that
has
information on the content store 412 receives a report from the content
tracker 404.
At some later point, further information from the local content catalog 416
is sent from the content tracker 404 to the content manager 312 in step 1128.
Expiration
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of a timer triggers this report in step 1132, but other embodiments could
report this
information when changes occur. With the reports from all the content
exchanges 116,
the content manager 312 stores the location information in the content
location database
320. Future queries to the content location database 320 by the content
manager allow
knowing which content exchanges 116 currently hold any content object the
content
manager 312 may want to redirect a client computer 112 to.
When reports of status information 420 and/or content catalog information
416 are made to a particular content manager 312, the content tracker 404
determines if
the content manager 312 is accepting the information. If the content manager
accepts the
information, processing loops back to step 1116 where another content object
is
requested.
If the content manager 312 is offline, for example, the reported
information from the content tracker 404 is not accepted. It may take several
unsuccessful attempts at contact before the content tracker 404 concludes the
content
manager 312 is unavailable. The non-responsive content manager 312 is detected
in step
1136. Any content objects associated with the unavailable content manager 312
are
determined by a query to the local content catalog 416. The associated content
objects
are purged from the content store 412 to preserve room for new content
objects, or they
are tagged for deletion when storage space is needed. It is noted that the
content tracker
queries the dynamic DNS 204 during the above process to translate an origin
server name
to an IP address.
Referring next to Fig. 12, a flow diagram of an embodiment of a process
for communicating information from a content manger to a server manager is
shown.
The depicted flow diagram shows the interaction between the active directory
104 and a
single origin server 108. It is to be understood, however, that the active
directory 104
interacts with a number of origin servers in a similar manner to develop an
electronic
directory that catalogs the number of origin servers in a server database 228.
The user
queries the server database 228 with a search page, or directory page
paradigm.
The process begins in step 1204, where the content manager 312 provides
status information to the server manager 208. The status information is
received by the
server manager 208 and stored in the subscriber database 224 in step 1208. The
subscriber database 224 holds information on all origin servers 108 currently
active in the
system 600.
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The server manager 208 can regulate how often each origin server 108
reports back with information from the local content catalog 316. The
frequency that
each origin server reports the local content catalog 316 is controlled by the
server
manager 208 providing a report-back time interval to the content manager 312
in step
1210. The loading or utilization of the active directory 104 is analyzed to
determine the
amount of bandwidth that is made available to updating information in the
server
database 228. Based upon that loading determination, a report-back time
interval is
chosen and passed to the content manager 312. In one embodiment, the report-
back time
interval is normally set to two minutes, but can increase if the active
directory becomes
overloaded.
Each origin server 108 maintains the local content catalog 316 of all
content obj ects selected by the administrator for publishing to the system
600. The first
time a content manager 312 contacts the server manager 208 to report the local
content
catalog 316, all the entries from the catalog 316 is sent. On subsequent
contacts only the
changes to the local content catalog 316 can be reported to save bandwidth. In
alternative
embodiments, the whole local content catalog can be reported with each
contact. The
server manager 208 receives the local content catalog 316 or changes to the
local content
catalog and stores the information in the server database 228 in step 1216.
Even if there
are no changes to the local content catalog 316 during the report-back time
interval, the
origin server 108 contacts the server manager 208 such that it is known that
the origin
server 108 is still available.
The server manager 208 detects if any origin server 108 stops contacting it
presumably because the origin server 108 is offline or otherwise unavailable.
In step
1220, the server manager 208 sets a timeout value for the origin server 108.
The timeout
value is set to three times the report-back time interval in this embodiment,
but other
multiples could be used. A counter is set for the timeout value and determines
when the
counter reaches the timeout value.
If the counter reaches the timeout value in step 1224, the active directory
104 removes all references to the origin server 108 or tags the references for
deletion
when space is needed in step 1236. It is presumed, that an origin server 108
is
unavailable if it does not initiate contact before the counter reaches the
timeout value.
The entries corresponding to the local content catalog 316 for that origin
server 108 are
removed from the server database 228 and the entry for the origin server 108
is removed
from the subscriber database 224. By removing the entries from the databases
224, 228,
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any user interfacing with the directory or search pages 212, 216 is not
presented links to
content objects associated with that origin server 108. Alternatively, the
entries
corresponding to the local content catalog 316 may be tagged for deletion
after the
counter reaches the timeout value. Content objects tagged for deletion are
overwritten
when the space is needed for other content objects.
If there is contact by the origin server 108 as determined in step 1228, the
active directory 104 knows the origin server 108 is behaving properly. The
contact
results in resetting of the counter storing the timeout value. Processing
loops back to step
1210 where the server database 228 is updated and a new report-back time
interval is
determined. The process continues in the loop until the origin server 108
fails to report
before the counter storing the timeout value expires.
Referring to Fig. 13, an embodiment of a flow diagram of a process for
publishing information by a content manger 312 to a server manager 208 is
shown. An
administrator of the origin server downloads software from a download page 220
of the
active directory 104. The software is installed on the origin server 108. At
this point,
content objects are available on the content server 308 in static or streaming
form. The
depicted process begins in step 1304 where the origin server begins operation
with
content objects ready and software installed.
The administrator performs a manual selection process to select content
objects in step 1308. Only a subset of the content objects on the content
server 308 may
be made available to the system 600 during this process. The selected content
objects are
entered into the local content catalog 316.
Upon first contacting the active directory 104, the content manager 312
passes information about the origin server 108 to the server manager 208 for
entry into
the subscriber database 224 in steps 1308 and 1312. If this is the first time
the content
manager 312 is contacting the active directory 104, the administrator may
provide some
of the information that is passed. The information added by the administrator
is stored
and provided with subsequent contact with the subscriber database 224.
In step 1316, the content manager 312 contacts the server manager 208 to
publish the information in the local content catalog 316. The server manager
208 takes
the local content catalog 316 and creates an entry in the server database 228
for each
content object in step 1320. The contents of the server database 228 are used
when
formulating the directory and search pages 212, 216 presented to the user
searching for
content.
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The server manager 208 controls the frequency at which all the origin
servers 108 report their local content catalogs 316. If the server manager 208
is getting
overloaded, the report-back period given to content managers 312 is increased.
The
server manager 208 can also request a content manager 312 to report-back when
changes
to the local content catalog 316 are detected. In this embodiment, the report-
back period
or interval time is two minutes and is provided to the content manager 312 in
step 1324.
Before reporting back to the server manager 208, the content manager 312
waits for the interval time to expire in step 1328. Once the timer expires,
the content
objects on the content server 308 are scanned to determine if there should be
changes to
the local content catalog 316. Once changes are made in step 1332, the
processing loops
back to step 1316 where the local content catalog 316 is published to the
server database
228 once again. The whole local content catalog could be provided in step 1316
for the
first contact, but only changes could be provided to update the information in
subsequent
contacts to reduce the size of the information.
Referring next to Fig. 14, a block diagram of an embodiment of the
content exchange 116 which shows multiple providers connected through separate
ports
1408 is shown. Three datapaths 1404 are logically separated by Internet
protocol ports
1408 for the content exchange 116. The ports 1408 are used to demultiplex the
logical
datapaths 1408 even though they may physically share a common conduit. By
having
multiple ports 1408, the traffic associated with those ports 1408 can be
regulated.
For example, the content exchange 116 may be used to provide content
objects from an external origin server 118. The administrator of the external
origin server
may wish to divide traffic between three bandwidth providers. Port A 1408-A
could be
associated with provider A, port B 1408-B could be associated with provider B
and port C
1408-C could be associated with provider C. The content exchange can monitor
activity
on any of those ports and report that information to the providers such that
they can bill
the external origin server 118 appropriately for carrying that bandwidth.
The requests from the client computers 112 could be divided among the
ports 1408 according to a scheme determined by the external origin server 118
to allocate
bandwidth among the providers. In one embodiment, each client computer 112
cycles
through the three ports 1408 according to a weighting function. In another
embodiment,
each client computer is assigned a different port 1408 to use. In yet another
embodiment,
a determination of QOS for each port 1408 influences the choice of port 1408
the client
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computer 112 uses. By using these techniques, the client computers 112 in the
system
,600 can influence the amount of bandwidth that is purchased from each
provider.
With reference to Fig. 15, a block diagram of another embodiment of the
content exchange 116 which shows multiple providers connected through separate
addresses 1508 is shown. In this embodiment, three IP addresses 1508 are used
to
logically separate the three datapaths 1504 from each other. Although the
logical
datapaths are primarily envisioned to separate bandwidth by provider, the
logical
datapaths could separate security levels, subsets of content objects, or other
things.
Referring next to Fig. 16, a hierarchical representation of an embodiment
of grouping of providers 1604 and content exchanges 116 is shown. In this
embodiment
there are two bandwidth providers 1604. Each provider 1604 has a site 1608-1,
1608-3
exclusive to themselves and a site 1608-2 that is shared. Sites 1608 are
physical locations
that house one or more servers 1612'and correspond to a single content
exchange 116 that
could include multiple servers 1612.
Each server 1612-3 in a shared site 1608-2 has separate IP addresses 1616-
3, 1616-4 for each provider 1604 sharing that site 1608-2. The two IP
addresses 1616-3,
1616-4 allow logical separation of the traffic to a given shared site 1602-2.
Logical
separation allows attributing content object requests and the bandwidth to
service those
requests to individual providers 1604 even though all traffic may share the
same physical
conduit at times. Some embodiments could keep the traffic associated with each
provider
physically separate by filtering on the IP address 1616. In this way the
bandwidth may be
allocated among providers 1604.
Referring next to Fig. 17, a hierarchical representation of another
embodiment of grouping of providers and content exchanges. In this embodiment,
ports
1716 are used to differentiate logical datapaths to servers 1612. Port one
1716-3 is
associated with provider one 1604-1 and port two 1716-4 is associated with
provider two
1604-2 on the sites 1608-2 that service multiple providers 1604. In some
embodiments,
each provider could have a range of ports associated with them rather than a
single
universal port on all servers.
Further, a content object provider is provided with a managed content
distribution system capable of providing sufficient QOS. Because a content
object is
provided from a transfer node, such as a content exchange 116, transfer of the
content
object to a requestor, such as a client computer, is transparent to the
content object
provider. The content object provider merely needs to associate an external
origin server
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to the content distribution system. Thus, instead of employing unpredictable
and costly
schemes of for distributing content objects, a content object provider need
only associate
with the content distribution system 100. This association effectively
virtualizes access to
content objects provided by the content object provider. Distribution
advantages of the
present invention are particularly important to small content object providers
who cannot
justify the costs associated with improving distribution.
Yet further, this method of providing content object providers with
distribution capability does not require a content object provider to provide
content
manager functions in an external origin server. Rather, the content object
provider gets
the benefit of any content manager existing elsewhere on the content
distribution system.
A number of variations and modifications of the invention can also be
used. For example, some embodiments could begin spooling the beginning of a
content
object from a content object store as the remainder of the content object is
retrieved from
other content exchanges and/or the content object server.
Although the invention is described with reference to specific
embodiments thereof, the embodiments are merely illustrative, and not
limiting, of the
invention, the scope of which is to be determined solely by the appended
claims.
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