Connectivity Monitoring object mandatory resource "IP Addresses" during non-IP binding.

[boria8]

• Name, version and date of the document, (e.g. OMA-TS-LightweightM2M-V1_0-20160802-C):
  OMA-TS-LightweightM2M_Core-V1_1 and above.
• Section of the document, (e.g. section: 6.2):
  E.5

How should the client respond to server READ requests when "IP addresses" are not available?

[sbernard31]

IP addresses resource (/4/x/4) is a resource multi-instance.
So at LWM2M level I guess we should expect a kind of empty list of resource instance.

But now the question is how you encode this kind of empty list of resource instance in different ContentFormat.

I guess for TLV there is no issue to do that.
For OLD_JSON and SenML(JSON/CBOR) this is maybe not so clear. There is a related issue about this #494 but we (Leshan and Wakaama developers) was not able to get a clear answer about this.

[boria8]

Maybe a possible solution is to make this resource optional so the client could have an option to not support this resource if the binding mode is non-IP?

[sbernard31]

I double check the last version of this object and this resource is still mandatory : 4.xml

Maybe a possible solution is to make this resource optional so the client could have an option to not support this resource if the binding mode is non-IP?

It could 🙂 . I guess the only drawback is that you can not see the difference between :

• a NOT_FOUND which means "I didn't implement this resource"
• and another NOT_FOUND which means "I have no IP address available".

(but maybe it doesn't matter)

Regardless of the solution chosen for this particular use case, the "blur" raised above (#529 (comment)) will still be there for other use cases.

[mkgillmore]

@sbernard31 is does this issue still need to be resolved? Do you have a work around we can adopt to address this issue?

[sbernard31]

A clarification of #494 is still needed.

At Leshan side we decide to implement that : eclipse-leshan/leshan#915 (comment)

[mkgillmore]

@sbernard31 I've tagged this for the LwM2M 1.3 release

[sbernard31]

Thx @mkgillmore 🙏 !