Re: [kmip] Protocol versioning

[Tim Hudson <tjh@cryptsoft.com>]

On 22/01/2011 7:12 AM, Bruce Rich wrote:
> I took an action item on the last TC call to write a note to the 
> reflector, requesting that folks cogitate a bit about KMIP versioning.

The objectives of what a major and minor protocol version is meant to indicate
should be captured clearly with the concepts of cross-version interoperability
in mind.

There are various aspects in the protocol which allow for determining what
'features' are supported already (the QUERY operation) and there are extensions
available for each defined enumeration and also vendor defined tags.

The "usual" approach is for a major version change to indicate incompatible
changes in the protocol and a minor version change to indicate compatible
versions which should be 'safe' to handle. And this should be about the protocol
itself and not about the version of the specification supported in my opinion.

Some guidelines we need to establish:
- adding a new operation should not change the major version
  (as this can be indicated with the QUERY operation)
- changing an existing structure in an incompatible manner
  should change the major version

Issues to discuss:
- how do a client and server determine the 'right' version to use when both
support a range of versions
- how does a client discover the full range of versions supported by a server

Tim.