Re: [cf-dev] Do you use CoapClient API?

[Simon Bernard <contact@xxxxxxxxxxxxxxx>]

Le 28/04/2016 12:43, Kovatsch Matthias a écrit :

From: cf-dev-bounces@xxxxxxxxxxx [cf-dev-bounces@xxxxxxxxxxx] on behalf of Simon Bernard [contact@xxxxxxxxxxxxxxx

Le 28/04/2016 09:10, Kraus Achim (INST/ESY1) a écrit :

Hi Simon,

 

Ø  What do you mean by several notifications transfered?

 

>This is the case where notifications is sent using blockwised (block2). If you send notification faster then server are able to handle (using block2), you can have several notification handle at the same time. Before as we have only one exchange for all the notifications, we dropped the older notifications. Now we are able to handle several at the same time.

 

If a resource, which is transferred blockwise, changes more frequently than you can transfer it, there is no guarantee that you still can read the old one!

Only the “memory monster approach of californium with its own in memory copy” will do that. For the most embedded devices I would guess, that they

could only provided the last version. (The blockwise therefore mentions to use E-Tag option to ensure, that the blocks of the resource belongs to the same

version of the resource).

Just to be clear about this point. This new behavior is not a wish, this is just a consequence. I just try to be exhaustive about the behavior changes.

[MK] The result, that this is now possible is an indicator that the concept behind Observe is now violated. The whole point of Observe is to make state synchronization scalable. Did you have a look at Carsten's mail that I forwarded (Re: Events, Subscriptions, Link Bindings, and RESThooks)?

Sry I missed the mail, I just read it. I think I get Carsten's meaning but I'm not sure to see the violation problem...
Did you mean that the current PR  made the Observe less scalable because of this ? Even if it's true, did you think this is a blocker issue ? As Achim said, there is not so many device which should be able to do this.
I would like to highlight that this is the current behavior for notifications transfered without blockwise. (I mean in master and 1.0.x branch)
If this is a blocker issue what did you propose ?

Best regards
Matthias

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