CPA negotiation removes all but one ChannelId element?

[Sacha Schlegel <sacha_oasis@schlegel.li>]

Hi CPA negotiation group

Sorting out preferences among elements is thought to be handled by the
CPA negotiation process.

Example:  To show the support of several transport protocols, a party
can have a list of several ChannelId elements in a
ThisPartyActionBinding element.

<CPP>
  ...
  <ThisPartyActionBinding ...>
    <BusinessTransactionCharacteristics .../>
    <ActionContext ...>
    <ChannelId>x</ChannelId>
    <ChannelId>y</ChannelId>
    <ChannelId>z</ChannelId>
  </ThisPartyActionBinding>
  ...
</CPP>

If the CPA negotiation process sorts out WHICH delivery channel is taken
(x, y, or z) does that mean that a CPA will allways have only ONE
ChannelId element per ThisPartyActionBinding element (variant a)?

OR does it just reorder the list (variant b)? 

sample variant a:

<CPA>
  ...
  <ThisPartyActionBinding ...>
    <BusinessTransactionCharacteristics .../>
    <ActionContext ...>
    <ChannelId>y</ChannelId>
  </ThisPartyActionBinding>
  ...
</CPA>

variant a: the CPA negotiation would make sure the two DelvieryChannels 
(of CPP one and CPP two) are compatible (might get tricky as the 
negotiation actors (human or computer) would need to know the 
interdependance of the elements/attributes). The CPA composition tool
might have provided the list of elements/attributes to check in its
NDD. Then once a delivery channel is chosen, the other delivery channels
and its NDD entries can be removed.

variant b: Compatibility  issue as in variant a. I could imagine, that 
a "dynamic" MSH could switch Delivery Channel in case that one 
Delivery Channel goes down, eg becomes unreliable. The MSH's then 
must be able to track both Delivery Channels. 

What is the consus of this one?

Kind regards.

Sacha Schlegel

PS: Just got Individual OASIS member yesterday, hurray
-- 
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