John,

What you describe is the intended behavior.

Thomas

On Wed, Nov 15, 2017 at 9:30 AM, Tengfei Chang <[email protected]>
wrote:

> Hi John,
>
> Before switching parent, the node still can keep synchronized to it's old
> parent through the TXRXSHARED cell. That cell is only shared between the
> node and its parent.
> The keepalive on TXRXSHARED cell should be able to keep the node
> synchronized.
>
> Tengfei
>
> On Wed, Nov 15, 2017 at 12:34 AM, john rubis <[email protected]>
> wrote:
>
>> I think the MSF draft states/infers this, but I wanted to verify.
>>
>>
>>
>> In the case a node has a valid preferred parent and wishes to switch to a
>> new one then:
>>
>>
>>
>> Dedicated link(s) to its current parent initially remain in place. This
>> way, while dedicated link(s) are being setup with the new, I’ll call it the
>> ‘Candidate Parent’, the node and its possible children remain connected and
>> reachable. During this period, the node also maintains its rank and time
>> synchronization to the current parent, not the candidate parent. Once
>> dedicated link(s) are established to the new parent, the node updates its
>> rank and time syncs to the new parent. All up stream packets now are routed
>> through the new parent and link(s) to the old parent are cleared.
>>
>>
>>
>> It has been observed in our system,  that the links to the new parent can
>> take some time to setup over the single minimal cell. Especially in dense
>> networks. This may cause a node to desync or loose connectivity for an
>> extended period of time.
>>
>>
>>
>> Thank  you,
>>
>>
>>
>> John Rubis
>>
>>
>>
>> _______________________________________________
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>> [email protected]
>> https://www.ietf.org/mailman/listinfo/6tisch
>>
>>
>
>
> --
> Chang Tengfei,
> Pre-Postdoctoral Research Engineer, Inria
>
> _______________________________________________
> 6tisch mailing list
> [email protected]
> https://www.ietf.org/mailman/listinfo/6tisch
>
>


-- 
_______________________________________

Thomas Watteyne, PhD
Research Scientist & Innovator, Inria
Sr Networking Design Eng, Linear Tech
Founder & co-lead, UC Berkeley OpenWSN
Co-chair, IETF 6TiSCH

www.thomaswatteyne.com
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