The value of svcTlsBackboneVplsStp specifies whether
STP is enabled on the Backbone VPLS specified by
svcTlsBackboneVplsSvcId.
An inconsistentValue error is returned if an attempt
is made to set this object when the value of
svcVplsType is not 'iVpls' or if an attempt is made
to set this object to enable when the value of
svcTlsBackboneVplsSvcId is set to the default.
The value of this object is set to disable
when the value of svcTlsBackboneVplsSvcId is set to
default.