Request for comments: routing through federations

[Joe M. Lamy (AEGIS.net)]

Hello Charles and Vassil,

I am working on a work item for ITI Tech called "MHD to a Federation" - although it refers to MHD, which is FHIR based, it isn't limited to FHIR. I'm also taking on some tasks to enhance mCSD to advertise service endpoints to any IHE actor, as well as to identify federated routing logic and mechanisms where there aren't any.

A federated routing example where the logic and mechanisms are already defined would be XDR ITI-41, using the Submission Set Intended Recipient.

Client A wants to send to recipient C, but can only get there through system B. Could be that A and B speak XDR and C speaks MHD, could be C is a person accessible through an internal messaging system, etc. Let's stipulate that it would be much better if A could look up a suitable endpoint for C and send directly to C. My use case is the fallback for when this can't be done.

Ok, so in XDR, A can send an ITI-41 request to B, identifying the Intended Recipient of C. XCDR is similar, identifying a HCID.

But we also have use cases to similarly target edge systems / recipients for transactions like XCPD and XCA query (XCA retrieve already targets a community). The Technical Committee has been looking at ways to do this.

For XCPD:

• Pass HCID or org id in HL7 receiver/device/id
• Pass HCID or org id in HL7 receiver/device/asAgent/representedOrganization/id (matching sender format; this is being done on eHx)
• Pass AAID in OtherIDsScopingOrganization (used by PDQV3 but omitted from XCPD)

and for XCA query:

• Route based on AAID in patient ID in request (this is being done on eHx)
• Pass HCID in AdhocQuery/@home

And I've been asked to reach out to you two, to check two things:

• To make sure I wouldn't be interfering with any routing in WS-Addressing or AS4.
• To see if I should be considering WS-Addressing or AS4 instead to do this multi-hop routing, where you send a message to B addressed to C.

Thanks.

Joe Lamy

Specification Expert

AEGIS.net, Inc.

joe....@aegis.net

www.aegis.net

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