Subject: RE: WG Review: Open Pluggable Edge Services (opes)

From: Mark Nottingham <[email-masked]>
Date: Mon, 18 Jun 2001 12:51:47 -0700

ALthough I've raised these concerns in the past, it seems appropriate to
reiterate them.

OPES wants to interpose an intermeidiary processing model into HTTP (and
possibly other application-layer protocols), to allow services to be
applied to messages as they pass through.

While there are many scenarios where this is useful (especially when
there is knowledge and consent from either or both endpoints),
there are others where it is dangerous (where there is no such knowledge
or consent). In such solutions, the only thing an intermediary can do is
to use heuristics to determine how to interpose services.

As such, the OPES goals break end-to-end transparency at the
application layer. As a result, (using HTTP as an example, because it
seems the first target of OPES), the publisher loses control over a
resource once it leaves their server. It then becomes impossible to
makes statements about that resource (e.g., P3P, Semantic Web, legal
status of a resource, etc.).

I suppose this would be fine if there was an active need for client- or
server-driven OPES vectoring in the market (e.g., integration of OPES
into the browser, or into content delivery networks, etc.). However, I
see no market for OPES in the CDN world, despite ICAP's existence for
more than two years, and nothing on the client side. Instead, the only
ICAP services to date seem to be targetted at ISPs (e.g., virus
scanning, content transformation, ad insertion, etc.).

While nothing stops intermediaries from doing this now, it's another
thing, IMHO, to encourage these practices by standardizing them. HTTP
(perhaps unfortunately) does not preclude transformation of messages by
intermediaries, so OPES has authority to do what it wants to with the
protocol. My problem is that it provides considerable power to
intermediaries, before there are mechanisms (trust, etc.) in place to
mitigate its effects.

Cheers,

-- 
Mark Nottingham, Research Scientist
Akamai Technologies (San Mateo, CA USA)

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From: "Scott Brim" <[email-masked]>
Date: Mon, 18 Jun 2001 16:23:44 -0400

Publishers lose control of how a resource is treated but still
(optionally) retain control over the resource itself, e.g. through
watermarks.  I doubt that publishers care if their content is carried
over Ethernet or ATM today.  How much do publishers care how their
content is encapsulated, routed, encoded, etc.?  What do you think OPES
could do that a publisher (1) would be concerned about, and (2) could
not protect against?

...Scott

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From: Mark Nottingham <[email-masked]>
Date: Mon, 18 Jun 2001 13:40:04 -0700

From the publisher/consumer standpoint, OPES is not about encapsulation 
or routing and very seldom about encoding.

These are the most common potentially damaging uses of ICAP, either 
currently in use or discussed:

   Insert ads.
   Insert a 'console' to 'brand' the browsing session.
   Rewrite links.
   Translate a document (changing its meaning)
   Redirect to a local copy of the resource (making it impossible to
     access the authoritative resource)

Does Ethernet do these things?

Of course publishers can protect against these things; they can run all 
of their content over SSL/TLS, watermark everything, etc. What if OPES 
is sucessful? Is the trust model of the Internet ready for this? The 
infrastructure (imagine if all HTTP traffic moved to SSL, making caching 
useless)?

Putting the burden of mitigating the effects of OPES onto content 
publishers and end users isn't a nice thing to do.

---

From: "Scott Brim" <[email-masked]>
Date: Mon, 18 Jun 2001 16:50:00 -0400

OK

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From: Daniel Senie <[email-masked]>
Date: Mon, 18 Jun 2001 17:00:37 -0400

At 04:23 PM 6/18/01, Scott Brim wrote:
>over Ethernet or ATM today.

>  How much do publishers care how their
>content is encapsulated, routed, encoded, etc.?

Publishers care if their content is damaged in flight (e.g. proxies which 
remove or alter content, which includes AOL's mangling of graphics). They 
also may care to know how many people and which people are accessing content.

>  What do you think OPES

I think OPES will further the sale of SSL accelerator boxes and web 
certificates. If the only way to protect content from uninvited third-party 
intermediaries, then content which is not otherwise confidential is going 
to be encrypted.

It's one thing if the publisher purposely buys the services of a content 
delivery network, it's quite something else when someone inserts a 
transparent proxy, especially one which alters the content.

> > status of a resource, etc.).

-----------------------------------------------------------------
Daniel Senie                                        [email-masked]
Amaranth Networks Inc.                    http://www.amaranth.com

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From: "Michael W. Condry" <[email-masked]>
Date: Mon, 18 Jun 2001 15:42:00 -0700

I think it is difficult for any working group to assume the responsibility
for assuring that everyone will do everything correctly in terms
of services, regardless of their location in the client-server chain. Yes, 
things
can be mis-used. You might consider Ad insertion a mis-use others
who get reduced cost ISP because of them might feel differently.

By looking at the framework and associated protocols we might come
with a operational model so that the content providers, service agents
and consumers know what they are getting into. I think we better
get that trust model well organized.

At 01:40 PM 6/18/2001 -0700, Mark Nottingham wrote:

>Of course publishers can protect against these things; they can run all of 
>their content over SSL/TLS, watermark everything, etc. What if OPES is 
>sucessful? Is the trust model of the Internet ready for this? The 

Michael W. Condry
Director,  Network Edge Technology

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From: Keith Moore <[email-masked]>
Date: Mon, 18 Jun 2001 20:15:55 -0400

> things can be mis-used. 

yes, but there's a difference between technologies that are accidentally
misused and technologies whose primary purpose seems to be abusive.
 
> You might consider Ad insertion a mis-use others

check out the Opera browser or the Eudora mail reader.  there are other ways 
to put advertisements on somebody's screen without corrupting the content.

Keith

p.s. so if the ISP uses opes to insert advertisements, can I as a customer
of that ISP also use opes to remove them?   if you say no, I claim you're
being unfair by putting the ISP's interest over *both* that of the content
provider and the consumer.  if you say yes, I claim that opes is a useless
technology that serves only to increase operational complexity and to sell
faster cpus.

---

From: John Stracke <[email-masked]>
Date: Tue, 19 Jun 2001 10:42:29 -0400

>    Insert a 'console' to 'brand' the browsing session.

[...]

> of their content over SSL/TLS, watermark everything, etc.

Or they can file suit for copyright violation: I put up my documents to be
distributed to end users; there may be an implicit license to redistribute
them from a caching proxy, but that does not include a license to
redistribute *modified* versions.

(In the US, an ISP who does ad insertion may even be committing criminal
copyright violation, since they're profiting from the violation.)

--
/=================================================================\
|John Stracke    | http://www.ecal.com |My opinions are my own.   |
|Chief Scientist |================================================|
|eCal Corp.      |You're just jealous because the voices only talk|
[email-masked]|to me.                                          |
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