Subject: feedback: OCP version head_sid2 thread

From: "Abbie Barbir" <[email-masked]>
Date: Sun, 6 Apr 2003 15:06:46 -0400

Hi, this is the feedback on the head-si2 ocp draft.

1. 
application message: A sequence of octets that OPES processor
      designates for callout service processing or a sequence of octets
      that callout server sends back to the OPES processor.  Usually, an
      application message is the basic unit of application protocol
      communication, as defined by that application protocol (e.g.,
      HTTP/1.1 message). (XXX: This definition is bad because OCP
      messages themselves are also sequence of octets that OCP agents
      send to each other.  How to distinguish "OCP" from "application"
      if we do not have an application data definition?  What we want to
      say is that application message is whatever an OCP agent has
      marked as such. How to say that?)

I still do not like this defintion at all.

An application message is still an application message whether OPES
processor
will send it to the callout server or not. We need to remember that in some
cases the OPES processor will do all the work and if a trigger happens such
as CPU watermark, the processor will use the callout server as an additional
helper.

Furthermore, The OCP should be application agnostic, here I think we should
differentiate between the following:

 Application  +---------------+   OCP Message    +----------------+
 Protocol --->| OPES Processor| ---------------> | Callout Server | 
 Message <--- |               | <--------------- |                |
              +---------------+                  +----------------+

In this regard, it is possible to have only one OCP binding to TCP/IP
regardless of the Application layer Protocol

The same thing can happen for data

 Application  +---------------+   OCP Data       +----------------+
 Protocol --->| OPES Processor| ---------------> | Callout Server | 
 Data    <--- |               | <--------------- |                |
              +---------------+                  +----------------+

The arrow can be uni or biderectional ( in the general case).

In some cases, the OPES processor can infere the adaptation that is needed
from the application message and send a service request to the Callout
server. For example:

1. Service Type: Crop image to QCIF size and make it B/W
2. Here is the URL for the image.