ExtAddress changes

[dakhnod]

When running ot-ctl extaddr, the cli reports some Address, which mostly stays persistent.
When I use the same RCP with another computer, or sometimes on the same computer, the ExtAddr changes.

Here are my questions:

1. When is the ExtAddr generated?
2. Under what circumstances does it change?
3. Besides the ExtAddr, how can I uniquely identify an RCP?
4. How can I uniquely identify a Border router?

[jwhui]

1. When is the ExtAddr generated?

Thread randomly generates a new Extended Address when the interface is commissioned.

2. Under what circumstances does it change?

See above.

3. Besides the ExtAddr, how can I uniquely identify an RCP?

You can try observing the EUI-64 value, which is a factory-provisioned unique identifier.

4. How can I uniquely identify a Border router?

How to uniquely identify a device is product specific. One possibility is by using the EUI-64.

[lancersky2017]

Hi @jwhui
Is there any way to know the mapping between EUI64 and Extended Address when the Joiner is commissioned?
The meshdiag command can only obtain Extended Address.

[jwhui]

The Joiner generates a new random Extended Address after successfully completing the commissioning process:

openthread/src/core/meshcop/joiner.cpp

Line 572 in d3d9163

Get<Mac::Mac>().SetExtAddress(extAddress);

The device will need to report its EUI-64 and Extended Address after to properly map them.

[dakhnod]

@jwhui Thanks, great! Is there a way to discover the EUI64 via CoAP diagnostics or similar?

[jwhui]

Yes, see:

openthread/include/openthread/netdiag.h

Line 67 in cb27207

#define OT_NETWORK_DIAGNOSTIC_TLV_EUI64 23 ///< EUI64 TLV

[dakhnod]

ah, perfect! thanks!