The CS 2.1 document states in section 15.7 that only the elements to
be modified are included in a modify request. However, in the schema
the p2p parameters directionality,
capacity, sourceSTP and destSTP are not optional. As a result the
example modify requests in figure 154 and 155 will not pass schema
validation.
If the four parameters are made optional in the schema it will also
be possible to leave them out in the initial reserve request, which
will cause problems because all four of them belong to the minimum
set of parameters in this stage. Or the schema is left as is making
it mandatory to always send the minimum set of parameters in every
modify request, in this case section 15.7 should be updated to
reflect this.