Re: [ws-rx] Issue i002 thoughts/proposal

[Anish Karmarkar <Anish.Karmarkar@oracle.com>]

Two corrections below (forgot to include the Sequence id).

-Anish
--

Anish Karmarkar wrote:
> All,
> 
> I had an action to send a proposal for issue i002 [1]. Here it is.
> 
> Issue i002 was raised during the 1st F2F. The issue was raised in the 
> context of long running Sequences where it was possible for the AcksTo 
> EPR to change. There was also some discussion on unending sequences (I 
> think Steve Winkler brought this up). In a long running Sequence it is 
> possible that the AcksTo EPR may change and therefore the RMS needs the 
> ability to let the RMD know of the new AcksTo.
> 
> Subsequently, I have been talking with our mobile folks and they have 
> brought up a different usecase (but which has the same issue):
> In the mobile world there are cases where the RMS is expected to have 
> different EPRs throughout the life of the Sequence (the device changes 
> cells/location/countries or is intermitantly offline), therefore it 
> necessary to provide the capability to change the AcksTo EPR for a 
> particular Sequence in progress.
> 
> Here is the outline of a proposed solution:
> 
> 1) The RMS is allowed to send a new message called wsrm:ChangeAcksTo 
> with the following pseudo-schema --
> 
> <wsrm:ChangeAcksTo Version="xs:unsignedInt" ...>

   <wsrm:Identifier ...> xs:anyURI </wsrm:Identifier>

>   <wsrm:AcksTo ...> wsa:EndpointReferenceType </wsrm:AcksTo>
>   ...
> </wsrm:ChangeAcksTo>
> 
> 2) The RMD responds with wsrm:ChangeAcksToResponse or a fault with fault 
> [Subcode] wsrm:ChangeAcksToDisallowed. wsrm:ChangeAcksToResponse has the 
> following pseudo-schema --
> 
> <wsrm:ChangeAcksToResponse Version="xs:unsignedInt" ...>

   <wsrm:Identifier ...> xs:anyURI </wsrm:Identifier>

>   ...
> </wsrm>
> 
> The /wsrm:ChangeAcksToResponse/@Version has to contain the same value as 
> the corresponding one in wsrm:ChangeAcksTo
> 
> Version numbers are strictly monotonically increasing numbers starting 
> at 1 (the AcksTo EPR in the CS message being version 0).
> 
> The reason to have a version number in the exchange is because 
> wsrm:ChangeAcksTo message may be retransmitted/lost/delayed/received 
> out-of-order and it is necessary to prevent the RMD from regressing to a 
> previous AcksTo.
> 
> On sending a wsrm:ChangeAcksToResponse message, the RMD sends subsequent 
> acks to the new AcksTo EPR.
> 
> Comments?
> 
> -Anish
> -- 
> 
> [1] 
> http://www.oasis-open.org/apps/org/workgroup/ws-rx/download.php/14604/ReliableMessagingIssues.xml#i002 
>