---+ HeaderProposalThree
The header is used in both requests and responses to communicate directly with a single resource (datasource). Examples:
---+++++ Header from a "manual" request sent directly to a resource
Note: in this case no software has been specified, and there's only a single source element.
---+++++ Header from a response to the previous request
Note: the source address in resource responses must be the exact accesspoint of the resource, otherwise clients won't be able to easily identify which response belongs to each resource.
---+++++ Header from a client software request that has been dispatched by a portal
Note: Intermediaries such as portals (MessageBrokers) are not obliged to include a source element in the header, although that's a recommended behavior.
---+++++ Header from a more detailed response to the previous request
Note: each "source" has the freedom to specify other related software.