Adapt different identifiers for the same thing across Bounded Contexts

Question

Meanwhile, I learned that Aggregate Roots should be wired explicitly by identifiers, not by actual associations to the other AR.

What if, for technical reasons, the identifiers of a same "thing" are different ones because I am not able to influence them?

Look at this picture for example,

(Source: http://martinfowler.com/bliki/BoundedContext.html

Imagine the Support Context is a total different third party system and uses its own identifiers, and I am not able to put my identifier in that system in any way.

So, in my Sales Context I am the master of the identifiers, my Customer and Product have identifiers which I gave; and I need to somehow wire the Sales Context's Customer to the Support Context's Customer.

Where would that adaption take place?

Answer 1

The most likely place is the anti corruption layer of the Sales Bounded Context under your control. You can keep a simple mapping around that translates from and to the Support Bounded Context identifiers. The relationship between these contexts will influence how you'll go about it. I suppose a product is sprouted from R&D and makes it into something that is put in the catalog by sales which - once sold - will need to be supported. Granted, this is guess work on my behalf.