Hello,
The <entry-ref/> and <external/> elements serves different purposes:
- <entry-ref/> is used to reference an <entry/> element. It can be defined
in another document but must be under the same XCAP root (RFC 4826 Para.
3.1). This way, the same <entry/> element can appear at different places by
reference and be defined in one place. The reference is relative as the
document and the reference share the same XCAP root.
- <external/> is used to reference a whole <list/> element.The list can be
defined in another document but it can also be placed on another server (RFC
4826 Para. 3.1). This way, composite list can be constructed (as defined in
OMA and RCS). The anchor is absolute as the anchor can be an another server.
Moreover:
- In OMA and RCS, it is common to use <external/> to build aggregate groups
("oma_grantedcontacts" contains "oma_buddylist", which contains
"oma_pocbuddylist", etc).
- It is common that anchors in <external/> elements reference the XDM
aggregation server XCAP root, which hides on which server the anchored
<list/> is stored. This adds a level of indirection that help hide real XDM
topology.
Regards, Laurent Etiemble.
Need an IMS Client ?
Try out the Mercuro IMS Client
Full support for OMA/3GPP XCAP/XDMS
More info at: http://www.mercuro.net/
2010/2/19 Iñaki Baz Castillo <[email protected]>
> Hi, RFC 4826 allows the usage of <entry-ref> and <external>:
>
> The <external> element is similar to the <entry-ref> element. Like
> <entry-ref>, it is only meaningful in documents obtained from an XCAP
> server. It too is a reference to content stored elsewhere. However,
> it refers to an entire list, and furthermore, it allows that list to
> be present on another server.
>
> I've realized that OMA and RCS specifications just do usage of <external>.
> I
> don't agree the "advantage" mentioned above for <external>, as the XCAP
> servers can know by itself the exact location of a XCAP
> resource/application
> without the need of inspecting the server URI and port.
>
> And also the usage of <external> introduces a complexity: if the server
> domain/port changes the document becomes unreachable. So, why to use
> <external> rather than <entry-ref>?
>
>
> --
> Iñaki Baz Castillo <[email protected]>
>
> _______________________________________________
> Sip-implementors mailing list
> [email protected]
> https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
_______________________________________________
Sip-implementors mailing list
[email protected]
https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
