Subject: [dtn] AMP comment on types

From: Brian Sipos <[email-masked]>
Date: Wed, 30 Mar 2016 18:36:00 +0000

This is a comment against "draft-birrane-dtn-amp-01".

It appears that all of the AMP data types are encoded as self-terminating units, i.e. given an indefinite-length octet stream each type can be unambiguously decoded from the stream. There is no need to have either an external encoded-size indicator nor an end-of-data marker.

If this is accurate, it would be useful to state this within the AMP data type discussion so that it is an apparent and obvious attribute of these types. Knowing this would assist in AMP implementation, and would provide guidance to AMP spec edits.

In fact, spec changes from amp-01 to amp-02 introduced a few "(OPTIONAL)" values which breaks this self-terminating behavior for the SRL type. If the self-terminating behavior _is_ desired then these values should be controlled by a present/absent bit flag similar to other optional protocol elements.