The value of svcTlsBackboneVplsSvcId specifies the
Backbone-VPLS service associated with this service.
An inconsistentValue error is returned if an attempt
is made to set this object when the value of
svcVplsType is not 'iVpls'.
Setting the value of this object to its default
value will also set the value of
svcTlsBackboneVplsStp to its default value.