Subject: RE: [xri] Link Back?
[Resending due to accidental sending before msg was finished.] Nat, I believe where we are with regard to XRD2 linking back to XRD 1.0 is "profound simplicity". By that I mean that the backlink in XRD2 is nothing more than an <XRD:Subject> value that resolves back to XRD1. Another way to say it is that XRD linking involves two basic cases: 1) Independent linking. 2) Dependent linking. INDEPENDENT LINKING With independent linking, XRD1 has <XRD:Subject> value #1 (within the scope of XRD signing authority #1), and XRD2 has <XRD:Subject> value #2 (within the scope of XRD signing authority #2). The only link is a forward link from XRD1 in the form of an <XRD:Link:URI> that resolves to XRD2 (and OPTIONALLY this link also contains an <XRD:Link:Subject> whose value is equivalent to <XRD:Subject> value #2). In this case, XRD1 has an independent link to XRD2, but XRD2 has no backlink to XRD1. With this scenario, any number of XRD1s can point to XRD2, and all the links will still validate, because XRD2 is entirely independent. DEPENDENT LINKING With depending linking, XRD1 has <XRD:Subject> value #1 (within the scope of XRD signing authority #1), and XRD2 has ***the same*** <XRD:Subject> value #1. In this case, XRD 1.0 has the forward link (described above) and XRD2 has the backlink in the form of an <XRD:Subject> value #1 that is NOT within the scope of XRD signing authority #2. This "foriegn subject" triggers the XRD trust verification rule that a processor must resolve the <XRD:Subject> value #1 to verify that XRD1 has a forward link to XRD2. That's why I call this "dependent linking". Hope this helps, =Drummond > -----Original Message----- > From: Nat Sakimura [mailto:email@example.com] > Sent: Monday, July 06, 2009 4:41 PM > To: XRI TC > Subject: [xri] Link Back? > > Hi. > > Just wanted to know what is the status for link back from XRD2 to XRD1. > > I have seen a lot of discussion for forward linking XRD1 to XRD2, > but I am not so sure about XRD2 back to XRD1. > > Presumably, we can just define <rel> that signifies the link back, > but have we defined or discussed it? > > Regards, > > =nat > > --------------------------------------------------------------------- > To unsubscribe from this mail list, you must leave the OASIS TC that > generates this mail. Follow this link to all your TCs in OASIS at: > https://www.oasis-open.org/apps/org/workgroup/portal/my_workgroups.php