Confusing… Producers can’t by nature "roundtrip" because in that case, they also become consumers. The meaning is either nonsense, or should be clarified
If the concept is for a producer, to also act as consumer towards external sources in a publish/subscribe relationship or a request/response relationship, it need a clarification, which part the producer is responsible for.
Page 17
Line 25 Part 1
Section 9.1.9
Ed
Proposed Disposition of DIS 29500 Comment DK-0072 (Modified: 2007-11-08) Agreed; the following change will be made to Part 1, §9.1.9, page 17, lines 2526: Conforming producers that are also consumers are encouraged to roundtrip and preserve unknown relationships and their target parts. Similar Comments: DE-0126 , FR-0011 , GB-0038 , KE-0079 , PT-0029 , US-0262
