Hello Yvonne-Anne

Please see below

> In particular, this concerns resources such as flows that follow certain 
> routes,
> and bandwidth allocation. Depending on the traffic demands during
> alarm/emergency conditions, applications may decide to pre-empt or stall some
> of the ongoing traffic flows to accommodate new flows or to assign
> appropriate resources to existing flows. Is there a concept of priorities of 
> flows
> envisioned in the architecture?

2 things here
1) the schedule can be configured with some amount of Tracks designed for 
asynchronous control and alerting. The time slots will be opportunistically 
reused by best effort traffic to the same next hop if the flow is not present.
2) TSCH has the concept of priority. You can define a slotframe with a higher 
priority that you normally do not use, but if you do in emergency, it will have 
precedence.

> 
> Note that if there are cascading errors this often leads to an increase in 
> traffic
> (messages to trigger logging of abnormal conditions, alarms for operators, &).
> Certain protocols (e.g. GOOOSE) send bursts of messages in such situations
> (e.g., three messages with a very short time interval in between, while 
> normally
> one message every few seconds is sent) One could also envision applications
> having tighter control over network resources. For instance, an application
> might want to (i) increase the sensing rate (ii) activate additional sensors 
> (iii)
> create special routing paths, ... In current implementations the applications 
> are
> not designed to trigger such actions. However, the examples your point out can
> clearly be beneficial. As an easy and crucial part I see priorities and 
> bandwidths.
> 

Well, if the usage is not deterministic and not programmed in advance, 6TiSCH 
adds RPL to the picture. I think that this boils down to an interaction with 
OTF whereby slots would be granted in emergency and opposed to waiting for a 
statistical impact. Adding Diego here...


Cheers

Pascal

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