A set of flag bits which control the operation of the filter. Filters will not prevent packets from being accepted by the ES/1 as a final destination. The following bits are used: bit 13, bit 12, bit 11, bit 10. bits 9-8 used for filterFrame. bits 7-6 used for filterSource, filterSourceEnd, and filterSourceMask. bits 5-4 used for filterDest, filterDestEnd, and filterDestMask. bits 3-2 used for filterSrcLan. bits 1-0 used for filterField, filterOffset, and filterMask.