Subject: [core] transaction ID in COAP

From: Hari Hara Sudhan R <[email-masked]>
Date: Tue, 13 Jul 2010 14:51:04 +0530

Hi All,

I'm reading through the COAP specification.
Who is resposible for creating transaction ID?
Will the COAP application provide it as an argument to COAP implementaion
or
COAP implementation will automatically create a transaction ID for all
the requests made?

Thanks and Regards,
Hari Hara Sudhan R

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From: Klaus Hartke <[email-masked]>
Date: Wed, 14 Jul 2010 11:46:26 +0200

> Who is resposible for creating transaction ID?

The node that sends a confirmable (or non-confirmable) message.

A node that receives a confirmable message just echoes the transaction
ID in its acknowledgement/reset.

> Will the COAP application provide it as an argument to COAP
> implementaion or COAP implementation will automatically create
> a transaction ID for all the requests made?

The CoAP application "thinks" in REST and should not be aware of the
CoAP Transactions layer. So having the CoAP implementation
automatically create the transaction ID for all requests made sounds
like a good idea. (This is also what coap-01 section 2.2.5. indicates;
have a look at that section for requirements on how a transaction ID
should be created.)

Klaus