Internet DRAFT - draft-beck-opes-esfnep
draft-beck-opes-esfnep
Internet Draft A. Beck
M. Hofmann
Lucent Technologies
M. Condry
Expires: May 2001 Intel Corporation
Document: draft-beck-opes-esfnep-01.txt November 21, 2000
Category: Informational
Example Services for Network Edge Proxies
Status of this Memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026 [1].
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Table of Contents
1 Introduction...................................................2
2 Virus Scanning.................................................3
2.1 Abstract.....................................................3
2.2 Business model...............................................3
2.3 Technical Challenges.........................................4
3 Insertion of Ad Banners........................................4
3.1 Abstract.....................................................4
3.2 Business model...............................................4
3.3 Technical Challenges.........................................4
4 Insertion of Regional Data.....................................5
4.1 Abstract.....................................................5
4.2 Business model...............................................5
4.3 Technical Challenges.........................................6
5 Caching of Personalized/Customized Web Pages...................6
5.1 Abstract.....................................................6
5.2 Business Model...............................................6
5.3 Technical Challenges.........................................6
6 Content Adaptation for Alternate Web Access Devices............6
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6.1 Abstract.....................................................7
6.2 Business model...............................................7
6.3 Technical Challenges.........................................7
7 Limited Client Bandwidth Adaptation............................8
7.1 Abstract.....................................................8
7.2 Business model...............................................8
7.3 Technical Challenges.........................................9
8 Adaptation of Streaming Media..................................9
8.1 Abstract.....................................................9
8.2 Business model...............................................9
8.3 Technical Challenges.........................................9
9 Request Filtering..............................................9
9.1 Abstract....................................................10
9.2 Business model..............................................10
9.3 Technical Challenges........................................10
10 Request Filtering through Content Analysis....................10
10.1 Abstract...................................................10
10.2 Business model.............................................11
10.3 Technical Challenges.......................................11
11 Creation of User Profiles.....................................11
11.1 Abstract...................................................11
11.2 Business model.............................................11
11.3 Technical Challenges.......................................12
12 Search Engine Index on Cached Web Pages.......................12
12.1 Abstract...................................................12
12.2 Business model.............................................12
12.3 Technical Challenges.......................................13
13 Language Translation..........................................13
13.1 Abstract...................................................13
13.2 Business model.............................................13
13.3 Technical Challenges.......................................13
14 Author's Addresses............................................14
15 References....................................................15
1 Introduction
The rapid growth of the Internet and the increasing number of
Internet users have resulted in many scaling and growth problems
with application designs focused on operations at the ends (i.e. the
client or the server). This has led to a wide deployment of network
edge caching proxies as a key strategy to address these problems.
These systems have been very successful in accelerating Web content
delivery and reducing the load on origin Web servers.
However, the specific role of these network edge caching proxies as
a gateway between Web users and content providers suggests utilizing
them for intelligent services beyond simple caching.
There are already a variety of existing or proposed approaches that
implement particular services on top of a proxy platform. ICAP [5]
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extends the basic idea of implementing value-added services on
proxies by handling transport of web objects between proxies and
content modification servers, thus, enabling remote call out
mechanisms. EPSFW [2, 7] describes an extended framework to provide
general services on top of an open proxy platform.
This document discusses several service examples possibly being
implemented on top of an open proxy platform as described in [2, 7].
Each of the following service description consists of three
subsections: a short abstract that describes the service idea, a
description of the underlying business model, and finally a section
that mentions technical challenges to be addressed when implementing
these services.
Section 2 describes virus scanning as an example service, which
currently is one of the most frequently cited service ideas. Section
3, 4, and 5 describe services that dynamically assemble personalized
content. These services exhibit the use of the proxy device managing
information about the client. Sections 6 and 7 present services that
adapt content to the capability of client devices and client access
bandwidth. Some of the previous service ideas can also be applied to
streaming media, which is discussed in Section 8. The services given
in Section 9, 10, and 11 operate on client requests rather than on
the content itself. More service examples are given in Sections 12
and 13.
2 Virus Scanning
2.1 Abstract
Viruses, Trojan Horses, and worms have always posed a threat to
Internet users. Just recently we have seen a number of e-mail based
worms that have hit millions of Internet users worldwide within a
few hours.
With the help of a content scanning and filtering system at the
caching proxy level, Web pages and also file transfers could be
scanned for malicious content prior to sending them to the user. In
Web pages active content like ActiveX, Java and JavaScript could be
scanned for harmful code (e.g. code exploiting security holes). File
transfers could be scanned for known viruses. If a virus is found,
the adaptation server could try to remove it or deny the delivery of
the infected content. A general rule could be that the caching proxy
may store and/or deliver content only, if it has been scanned by the
content adaptation server and no viruses are found.
2.2 Business model
This service could be offered as an additional feature to ISP
customers who are concerned about security issues. Likewise
enterprises could be interested in this solution to prevent any
malicious content from entering the company network.
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2.3 Technical Challenges
Web pages/files should be scanned for viruses by sending them to a
separate server where virus-scanning software would analyze them.
ICAP [5] is an example protocol for this purpose. The virus scanning
operations should not be performed on the caching proxy as they will
probably affect the performance of the caching proxy.
If HTTP file transfers are to be scanned for viruses and the
requested file cannot be found in the cache, we have to use a
different approach than for Web pages. It would not be feasible if
the proxy waited for the requested file to be received completely
before sending it over to the content adaptation server for the
virus scan. This approach would lead to a long delay at the userĘs
end, which is not acceptable. Instead, we would have to scan the
file transfer continuously, as it is being sent to the user (similar
to streaming media).
3 Insertion of Ad Banners
3.1 Abstract
Many Internet companies rely heavily on revenue made by selling
advertisement space on their Web pages. Whenever advertisement
banners are inserted dynamically depending on who requests the page,
they cannot be cached, even when the content of the page itself is
static. This behavior prevents Web pages from being cached, although
their static content would allow for it.
Therefore it seems reasonable to cache the static part of those Web
pages at a caching proxy near the client and to insert ad banners
into the cached Web pages before serving them to the client.
3.2 Business model
This service is a sales item to Internet advertising networks. They
obtain a market from customers wishing a low cost network access in
return for advertising. This is the free ISP market. Also, content
providers who do not want to outsource their ad space management and
sales might be interested in providing banner images and insertion
rules to proxies/content adaptation servers to accelerate the
delivery of their Web pages.
An ad insertion module at the caching proxy of the Free ISP could
insert ad banners (in addition to any ad banners from the content
provider) into every Web page requested by a customer. That way the
customers of the Free ISP will not have to install any special
software in order to use its service.
3.3 Technical Challenges
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The caching proxy would have to recognize when and where to insert
ad banners into a Web page before serving it to the client. The
proxy could for instance scan the Web page for a specific marking
(e.g. a special tag). In the case of a Free ISP ad banners would
probably always be inserted at the same position (e.g. in a frame at
the top of each page) or in a separate pop-up window.
If we wanted to insert advertisements based on the user and his
interests, we would have to identify the user (by using cookies for
example) and create user profiles. The user profiles could also be
provided by the content provider.
A standard model for identifying space where the content providers
allow for advertising insertion is critical. This will have to be
coordinated with groups defining content structure, such as XML with
W3C [4].
4 Insertion of Regional Data
4.1 Abstract
If a content provider wants to add user-specific regional
information (weather forecasts for certain areas for example) to his
Web pages, he has little choice but to have the user select his
location from a list of regions. Usually it is not possible for
origin servers to reliably detect from where Web users connect to
Web sites because user requests can get routed through a number of
proxy servers on their way from the client to the origin server.
In a network edge caching proxy environment user requests are
usually redirected to the nearest proxy that is available to respond
to the request. Regional information that is relevant to all users
who are likely to connect to a certain proxy could be stored at the
corresponding caching proxy. Whenever the proxy receives a user
request, a module on the caching proxy could insert the regional
information into the requested Web page. If the Web page does not
contain any user-specific non-cacheable content other than the
inserted regional information, the Web page content can now be
cached for future requests.
4.2 Business model
This service could be sold to content providers who want to offer
regional information on their Web sites and want to accelerate the
delivery of their Web content. There are many cases in which a
content provider could profit from knowing the location of the user.
Users could be targeted with regional advertisement banners (see
also ad insertion scenario). Regional distinctions (e.g. sales
taxes, differing laws etc.) could be taken into consideration when
the Web pages are prepared for the client. It would not be necessary
any more to ask the user for his location prior to presenting him
relevant information.
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4.3 Technical Challenges
The regional content that is to be inserted into the Web pages would
have to be distributed to the corresponding caching proxies. Since
the regional content represents only a component of a whole Web
page, it cannot be cached in the same way a complete Web page can be
cached (unless it is an image). We have to find a mechanism to
determine when a regional text component needs to be updated (or if
the content provider should be responsible for this).
5 Caching of Personalized/Customized Web Pages
5.1 Abstract
Many Web sites (e.g. Yahoo) offer a service where users can create
their own personalized version of the Web site (e.g. MyYahoo). It
basically means that a user can choose from a number of components
(e.g. stock information, weather forecasts, news etc.) and create a
personalized Web page with them. This leads to dynamic Web pages
that usually cannot be cached. However, the components of the
personalized Web page can be cached. Therefore, it is possible to
have a service module on the server create the user-specific Web
pages by assembling the cached Web site components. In that case the
origin server would not have to be contacted again and the page
could be served to the client directly from the network edge caching
proxy.
5.2 Business Model
This service would be another method of accelerating the delivery of
Web content to the user, particularly the delivery of
personalized/customized Web pages that would not be cacheable
otherwise. It also saves bandwidth between the origin server and the
proxy cache.
Content providers who offer their customers the possibility of
personalizing their Web pages are likely to be willing to pay for
this kind of service.
5.3 Technical Challenges
We would have to find a caching mechanism for the separate
components of the personalized Web pages (unless a component
consists of an image only). These components could be stored at the
caching proxy.
The page components would have to be refreshed just like complete
Web page whenever they become stale.
6 Content Adaptation for Alternate Web Access Devices
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6.1 Abstract
There is a growing diversity and heterogeneity in types and
capabilities of client devices as well as the forms of network
connections that people use to access the Web. Clients include cell
phones and PDAs as well as PCs, TVs (with SetTop boxes), etc.
However, these appliances have quite diverse display capabilities,
storage, processing power, as well as slow network access. As a
result, Internet access is still constrained on these devices and
users are limited to only a small fraction of the total number of
Web pages available in the Internet today. Organizations such as the
WAP forum [4] have suggested custom Web page design but this results
in special code frequently required on the content server.
Since the number of different access devices is growing constantly
content providers cannot be expected to provide different versions
of their Web pages for each and every Web access device that is
available in the market.
Therefore, if it is possible to transcode the general full-fledged
Web pages at some point on their way from the origin server to the
user so that they are optimized for (or at least adapted to) the end
users' specific requirements, it would provide a valuable service
for the end customer, the service provider, and the content
provider.
6.2 Business model
With the above-mentioned service in place, Web content providers
could reach a much wider audience and the manufactures of diverse
Web access devices could offer potential customers access to a
bigger part of the Internet content, which should make a very good
selling point. It would encourage more people to buy non-desktop Web
access devices like cell phones and PDAs expanding the market.
We would expect this service would be offered as an additional
feature to ISP customers who want to access the Web through
different Web-enabled devices. Also, the service might be paid by
content providers because they could serve their existing content to
more users; likewise, the non-desktop device makers may contribute
to this service cost making their client devices more effective at
the Web.
6.3 Technical Challenges
Possible adaptations to meet the special requirements of different
Web access devices are:
- Conversion of HTML pages to WML (Wireless Markup Language) pages
- Conversion of JPEG images to black and white GIF images
- Conversion of HTML tables to plain text
- Reduction of image quality
- Removal of redundant information
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- Stripping of Java applets / JavaScript
- Audio to text conversion
- Video to key frame or video to text conversion
- Content extraction
We have to ensure that the automatic adaptation process will not
make changes to a Web page that are unwanted by either the content
provider or the recipient. Our suggested strategy to achieve this
would be to allow the content provider as well as the client to
define their preferences as to how they want Web pages to be
adapted. The actual adaptation decisions would then be made based on
the given preferences and a set of transformation rules. There would
have to be a mechanism of resolving potential conflicts between the
content provider's and the user's adaptation preferences. If neither
the content provider nor the client has expressed his preferences, a
default adaptation of the requested Web page may be possible but
investigation is needed.
A way for preferences to be specified representing the content
provider and client customer must be provided. For example, client
customers could set their preferences through a Web interface on the
ISP Web site. Content providers could express their preferences by
adding meta tags to their Web pages. This meta data offers the
content provider the ability to specify a number of alternatives and
the content adaptation server could then pick the most appropriate
one. This meta data should be independent of specific Web content
but is likely to depend on the types of content in the pages.
Another possibility in the ESPWF [2, 7] framework would be for the
content provider would be to provide an adaptation policy to all
ISPs that want to adapt Web pages for alternate Web access devices.
This policy could consist of general transformation rules or actual
code modules that perform the adaptation.
7 Limited Client Bandwidth Adaptation
7.1 Abstract
Different Internet clients can handle different Internet connection
speeds. Therefore it seems desirable to adapt the requested Web
content to the userĘs bandwidth.
7.2 Business model
One of the main benefits is to decrease the Web access time for
users. If a Web site loads too slowly, users tend to leave the site
even before it has completed loading the home page. The improved
perceived quality of service by adaptive content delivery means that
users are more likely to stay and return, thus resulting in a
greater profit for e-commerce sites. This can also result in higher
hit rates and return rates, which can lead to higher sales for e-
commerce sites and higher advertising revenues.
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7.3 Technical Challenges
Possible adaptations to reduce the size of Web objects are:
- Reduction of image quality
- Replacement of images by their ALT text
- Removal of redundant information
- Removal of HTML comments
- Stripping of Java applets / JavaScript
- Audio to text conversion
- Video to key frame or video to text conversion
- Text summarizing
- Content extraction
We would have to find a reliable way of determining the bandwidth
between the client and the proxy cache. One way of measuring this
would be to measure the round trip time (RTT) to determine the
connection speed. It is crucial that this bandwidth detection method
works more or less exact or otherwise the client will either
experience very slow Web browsing or be cut off of some (or all) of
the rich Web content. This service requires authorization by the
user like any other adaptation service that changes the content and
or format of Web pages.
The mapping of a userĘs connection speed to appropriate page
adaptations requires defining a set of adaptation rules.
8 Adaptation of Streaming Media
8.1 Abstract
Some of the above-mentioned services could not only be applied to
Web pages but also to streaming media like audio and video streams.
In particular, media streams could be adapted to meet the bandwidth
of the userĘs connection. It would also be possible to insert pre-
recorded advertisements into audio or video streams. Even content
analysis and content filtering could be applied to streaming media.
8.2 Business model
The business models for streaming media adaptation are similar to
those for Web page adaptation services.
8.3 Technical Challenges
The adaptation of streaming media will add more complexity to the
caching proxy platform and the technical challenges of these kind of
services have yet to be explored.
9 Request Filtering
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9.1 Abstract
The success of Web filtering/blocking systems like NetNanny
(http://www.netnanny.com) and WebSense (http://www.websense.com)
shows that there is a great need for solutions that let the owner of
a Web access device control what kind of Web content can be accessed
with his device. Parents, for instance, often demand a means of
blocking off offending material when their children browse the Web.
Also, companies might want to have control over what kind of Web
pages their employees can have access to. Companies might also want
to prevent their employees from using the available bandwidth
excessively for non-work related activities.
A request filtering service could provide a solution for all of the
above. If all Web page requests of a specific user are routed
through a caching proxy server, the content adaptation server could
analyze the requests prior to fulfilling them. The service module
would have to identify the user and determine the userĘs access
level. The next step would be to look up the classification of the
requested Web page in a database.
9.2 Business model
This service could be offered to enterprises and to ISPs. A database
of Web pages that contain offending material could be obtained from
companies that have specialized in Web blocking systems.
9.3 Technical Challenges
The database on the proxy caching platform that contains the Web
page classifications needs to be updated on a regular basis. If the
database is provided by third parties, we have to provide them with
a secure way of updating the database.
If a Web access device is shared among different users who have
different access levels, it is not sufficient to identify the Web
access device. Therefore it will probably be necessary that
different users of a Web access device use different user accounts.
The owner of a Web access device must be able to define and change
the access rights of the user(s) of his device. This could be done
through a Web interface provided by the ISP/company.
10 Request Filtering through Content Analysis
10.1 Abstract
While this service is very similar to the one previously described,
it works more dynamically in that the content adaptation server
analyzes the Web content once it has been retrieved from either the
proxy cache or the origin server prior to sending it to the client.
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Through the use of sophisticated content analysis algorithms it
should be possible to classify the analyzed Web content. If the
classification of the Web page matches the userĘs access level, the
page will be delivered to the client. Otherwise, the client will be
denied the page. The analyzed page along with its classification
should be stored in the proxy cache so that future requests for the
same page do not require the cached Web to be analyzed again. This
will result in a better Web page delivery performance for popular
Web pages. The main benefit of this approach is that there is no
need to provide or maintain lists of forbidden Web sites, a process
that per definition must always lag behind the creation of new Web
sites. If common characteristics of a category of unwanted Web pages
can be defined, it should be possible to automatically detect
whether a requested Web page falls in a forbidden category.
10.2 Business model
This service could be offered to enterprises and ISPs. The content
analysis software could be obtained from software companies that
have specialized in this field.
10.3 Technical Challenges
In addition to the technical challenges described in the previous
service scenario, we would have to find a way of storing the
classification information of Web pages once they have been
analyzed. One way to do this would be to add a meta tag (possibly
using the Resource Description Framework [6] specification) with
content rating information to a Web page before it is cached.
Subsequent requests of the same Web page would then require the
request filtering service module to scan the cached Web page for
this metadata in order to determine the content rating of the
requested page.
11 Creation of User Profiles
11.1 Abstract
If all Web requests of a certain Web user were routed through a
certain caching proxy platform, it would be easy to log them in
order to create a profile of the userĘs Web browsing behavior. These
user profiles could be created anonymously with no personal data
(e.g. name or e-mail address) stored in the access log files.
Once a sufficient number of requests has been logged by the content
adaptation server, the marketing group could start analyzing the log
files. In most cases it should be possible to derive the userĘs
interests by analyzing what kind of Web sites the user visits and
how often he goes there.
11.2 Business model
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Companies that want to advertise on Web pages are very interested in
knowing more about the recipients of their advertisement campaigns
so that they can target their advertisements at people who are
interested in the kind of products/services that the company wants
to sell. These companies will pay for information that helps them to
target their campaigns at interested users. This money could be
offered to users (e.g. in the form of reduced Internet access fees)
to give them an incentive to agree to the profiling.
As explained above, we could derive the userĘs interests from his
Web browsing behavior and use this information to send the user only
those advertisements that match his interests/needs. This will most
likely result in a higher ad banner click-rate per user.
This service could be sold separately or in combination with the ad
insertion service.
11.3 Technical Challenges
The creation of user profiles requires a mechanism to identify Web
users. The ISP could provide a mapping from the userĘs (possibly
dynamic) IP number to some unique user ID. Another alternative would
be to use cookies, provided that the user has not disabled them in
his Web browser.
12 Search Engine Index on Cached Web Pages
12.1 Abstract
A proxy usually contains the most frequently requested Web pages of
the Web users whose Web requests are routed through it. If we
indexed the content of all Web pages currently contained in one or
more proxies, we would have an index of Web pages that Web users are
very likely to request (since they have been the most popular in the
past). A search engine based on this index could therefore yield a
high hit rate when used by a group of users who have similar
interests and usually connect to the same caching proxies. The
benefit of this approach would be that the index could be created
very fast (there is no Web crawling to do) and that the search
results could be returned to the user directly from the network edge
caching proxy. The drawback, however, is that this search engine
would index only a small fraction of the existing Web pages. Web
users have to be aware of this fact when they use the cache-based
search index service. Another approach would be to display the proxy
search results first while a global search engine prepares the
results of a global search in the meantime. As soon as the global
search results become available, they will be sent to the user.
12.2 Business model
The search engine service described above could be sold to big
companies who have users with similar interests and want to provide
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a fast search engine. Companies offering traditional search engines
could be interested in combining their services with a cache-based
search engine service to accelerate the delivery of their search
results.
12.3 Technical Challenges
If the cached Web pages of more than one caching proxy were to be
indexed, we would have to find a way of replicating the search index
to all affected caching proxy servers.
13 Language Translation
13.1 Abstract
Soon the majority of all Internet users will be non-English
speaking. As most of the current Web content is written in English,
it becomes desirable to be able to translate the English content to
the Web userĘs local language, even if the content provider does not
offer translations of his Web content. An automatic translation
service for all Web pages could be implemented with a content
adaptation server.
The proxy server will determine the Web user's preferred language(s)
and ask whether the content requested should be translated to the
user's preferred language. If the content is to be translated, the
proxy cache will forward the Web content to a translation server
where the page then is automatically translated. The proxy could
also locally store translated content eliminating the need to repeat
translations for different users.
13.2 Business model
The automatic language translation service will help break language
barriers and open new markets for e-commerce. The average non-
English speaking Web user will have access to more Web content.
ISPs, especially those with customers in non-English speaking
countries, could offer this service to their customers.
13.3 Technical Challenges
The automatic translation of text found on Web pages is not a
trivial task. It will not be possible to translate a Web page
automatically without running the risk of rendering parts of it
incomprehensible. Worse yet, the original meaning could be changed
and it is not said the reader of the translated page will notice the
change in meaning. It is questionable whether content providers
would even tolerate this kind of translation service.
Therefore it is very important that the client authorizes this
translation service and is fully aware of its potentially faulty
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behavior. It should also be considered to mark translated pages in a
specific way to remind the user of the machine translation.
Other technical challenges include the automatic detection of the
language used in the original document and the clientĘs local
language.
14 Author's Addresses
Andre Beck
Markus Hofmann
Bell Labs Research
Lucent Technologies
101 Crawfords Corner Rd.
Holmdel, NJ 07733
Phone: (732) 332-5983
Email: {abeck, hofmann}@bell-labs.com
Michael W. Condry
Intel Corporation
2111 NE 25th Avenue
M/S JF3-206
Hillsboro, OR 97124
Phone: 503-264-9019
Email: condry@intel.com
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15 References
1 Bradner, S., "The Internet Standards Process -- Revision 3", BCP
9, RFC 2026, October 1996.
2 Tomlinson, G., et al., "Extensible Proxy Services Framework",
Work in Progress, Internet Draft draft-tomlinson-epsfw-00.txt,
July 2000.
3 World Wide Web Consortium (W3C), http://www.w3.org.
4 The Wireless Application Protocol (WAP) Forum,
http://www.wapforum.org/.
5 ICAP Protocol Group, "ICAP - the Internet Content Adaptation
Protocol", submitted as Internet Draft draft-elson-opes-icap-
00.txt, (previous version available at http://www.i-cap.org/),
November 17, 2000.
6 Resource Description Framework (RDF), http://www.w3.org/RDF.
7 Open Proxy Extensible Services (OPES), http://www.extproxy.org.
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