tIPFilterParamsFwdSapPortId specifies the sap port identity of the
destination for this IP filter entry.
A value of 0 indicates that there is currently no SAP destination
defined. A value different from 0 can only be specified if the value
of the tIPFilterParamsAction object of this entry is 'forward'.
In addition a non-zero value can only be given if the object
tIPFilterParamsFwdSdpBind has a zero value.