The value of the object svcTlsBackboneVplsSvcISID specifies
a 24 bit (0..16777215) service instance identifier for
this service. As part of the Provider Backbone Bridging
frames, it is used at the destination PE as a
demultiplexor field.
The default value of -1 is used to indicate the value of
this object is un-specified.
This object must be set along with svcTlsBackboneVplsSvcId.
An inconsistentValue error is returned if an attempt
is made to set this object when the value of
svcVplsType is not 'iVpls'.