Hi,
Regarding version negotiation for backward compatibility, let me approach
the problem from IoTivity perspective.
Regarding versioning scheme, there were several discussion and proposals
but all has some problems.
However, I?ll list up the proposal as follows because of better than
nothing.
Proposal1. /oic/d resource with version attribute(property)
This will affect the communication sequence as /oic/d always
first for version negotiation.
Proposal2. Use the CoAP optional field for version.
This will be big overhead even if version info only take 1 byte.
(CoAP header is 4 bytes)
Proposal3. Use the CoAP optional field for version only in /oic/res.
We can reduce the packet size after discover done. But two
issues happens.
. IoTivity stack internally manager the resource and version
mapping list.
. Some corner cases : RD/GW case, real target device can have
different version, OTA updated stack can have different version after
discovery.
In case of not start from discovery, no version info(becuase discovery is
not mandatory step always..)
Please raise the idea to make version negotiation realized.
Greg, any idea for this?
BR, Uze Choi
From: Dwarkaprasad Dayama [mailto:[email protected]]
Sent: Wednesday, March 23, 2016 3:41 PM
To: 'Mitch Kettrick'
Cc: ???
Subject: RE: Backward Compatibility for IoTivity
Dear Mitch,
?icv? may solve in some case while it will not in some case.
Think about /oic/res schema change, if a device using new schema responds
to old versioned client, client will not understand the schema at all.
So I was thinking something out of band or using CoAP header to communicate
the version number.
But again, we just started this discussion and hence will have to think
about every possible case, and make sure sender and receiver are able to
know versions without getting into payload.
This topic has been assigned to OSWG - Developer Eco Build TG (Uze) with
Ravi, Greg to share their expertise. You can share your thoughts too.
Regards
Dwarka
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Software R&D Center | Software Platform Team | IoT Lab
Open Connectivity Foundation - OSWG - Spec Coordination TG Chair
Iotivity Steering Group - Advisory Committee
From: Mitch Kettrick [mailto:[email protected]]
Sent: Wednesday, March 23, 2016 9:47 AM
To: Dwarkaprasad Dayama
Subject: Backward Compatibility for IoTivity
Hi Dwarka,
I saw this slide. You do know that the ?icv? Property of /oic/d contains
the version of the core spec that each device is implemented to.
Does this solve part of the problem (i.e. each device signaling its
capability)?
Mitchy
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