[[Clause_Requirements]]
== New Requirements Statement

=== Status Quo

The current synchronization protocol is defined in document OGC 15-010r4,
OGC® Testbed-11 WFS-T Information Exchange Architecture.  As defined in OGC
15-010r4, the protocol allows synchronizing peers to request each other's
change sets since some specified checkpoint on a per-feature-type basis.

=== Requirements Statement

There are several issues with the synchronization protocol as defined in
OGC 15-010r4:

First, there is no way for a requesting peer to determine the size of the
change set that a responding peer would generate in response to a sync
request.  Thus, a means is required for a requesting peer to be able to
request the size of the changes set since some specified checkpoint.
This is akin to the resultType parameter defined for WFS GetFeature
request (see OGC 14-102, 7.6.3.6).

Second, if a requesting peer is only interested in a subset of features 
defined by some filter, there is no means for the requesting peer to
indicate that the responding peer prune the change set based on that 
filter.

Finally, there is no means currently defined for a requesting peer to
request that the responding peer resolve references that might exists
in the features in the change set.  Thus a means is required for a
requesting peer to be able to specify that the responding peer resolve
references.  This is akin to the resolve parameters defined for the WFS
GetFeature request (see OGC 14-102, 7.6.4).