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Re: OPES protocol, pre-draft

2003-03-16 23:34:37

Please apologize my late reply, but this just came to mind when catching-up with all the emails after coming back from vacation and reading through them for a second time on the plane...


Martin Stecher wrote:
Example 2:
Callout server analyzes beginning of application message and detects
that it is not interested in this app. message:

A. Traditional approach, ICAP/1.0 like with multiple preview
    0. C: Start of app. message 1
    1. C: Here is preview chunk 1
    2.                                S: Need another preview chunk
    3. C: Here is preview chunk 2
    4.                                S: Not interested (204 resp.)
    5. C: Start of app. message 2

B. Proposed OPES protocol
    0. C: Start of app. message 1
    1. C: Chunk 1 of data             S: Start of app. message 1
2. C: Chunk 2 of data 3. C: Chunk 3 of data S: Not interested 4. C: Chunk 4 of data 5. C: Start of app. message 2

In this case B sent more data and data chunks 3 and 4 will be ignored
by the callout server.

This might be obvious, but please allow me to add the following for clarification only... Chunks 3 and 4 can only be ignored (i.e. discarded) by the callout server if the OPES processor has sent them with the [copied] flag set in the respective <data-have amid offset size [copied]> message(s). If the [copied] flag was not set, the callout server must not ignore chunk 3 and 4, but simply copy/send them back to the OPES processor. Obviously, this can be done without further processing (i.e. servicing), but they still need to be sent back, since the OPES processor might no longer have a copy of these chunks. Note, that this is true even if chunks 1 and 2 were sent with the [copied] flag set.

Thanks,
  Markus



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