tMacFilterParamsFwdSapEncapVal specifies the sap port encap value
of the destination SAP for this Mac filter entry.
A value different from 0 can only be specified if the
tMacFilterParamsFwdSvcId object also has a non-zero value,
the tMacFilterParamsFwdSapPortId object has a non zero value,
and if the the value of the tMacFilterParamsAction object of this entry
is 'forward'.
In addition a non-zero value can only be given if the object
tMacFilterParamsFwdSdpBind has a zero value.
A value of 0 indicates that either
1) the sap encapsulation value is not specified when
tMacFilterParamsFwdSapPortId and tMacFilterParamsFwdSvcId
have valid values; or
2) that there is no SAP destination.