SequenceNumber

[cacamille3]

Hello,

I am using UA Expert 1.2.2 175
One I have 2 or more subscriptions with MonitoredItems from the same Server and with DataNotification publishResponses are emitted like :

Publish Response 1 - Subscription 1 - SequenceNumber 1 - DataNotification [...]
Publish Response 2 - Subscription 2 - SequenceNumber 2 - DataNotification [...]
Publish Response 3 - Subscription 1 - SequenceNumber 3 - DataNotification [...]

Then UA Expert ask for a Republish :
Republish Request - Subscription 1 - SequenceNumber 2
But there was no publish for Subscription 1 with SequenceNumber 2 since it was used by Subscription 2 !


So my question is :
Why UaExpert is using SequenceNumber counter per Subscription ?
I think there is a lack of precision about it in the specification since SequeceNumber counter might be per Subscriptions/Sessions/Servers.
Or do you know where I could find more precisions about it ?

[Support Team]

Hello,

The OPC UA specifications are unambiguous at this point. Please refer to Part 4 of the spec.

Best regards
Support Team

[cacamille3]

Ok, i found a bit more and I think i know what I got wrong.

SubscriptionAcknowledgment is linked to Session even if client send the SubscriptionId
SequenceNumber is linked to Subscriptions.

It means that if I receive a PublishRequest with 1 SubscriptionAcknowledgment for Sub1
and then I have a PublishResponse for Sub2, I shall also set the Results StatusCode to prove I deleted the queued DataNotification of Sub1...