This value is a byte offset from the beginning of the packet. If this offset is such that any portion of the filter extends past the end of the packet (for wildcard filtering purposes, the FCS is part of the packet), then the filter is considered not to match, and the packet is not filtered.

For a particular filter, the wildcardUserOffset must be greater than or equal to the wildcardOffset.

wildcardUserOffset must be between 0 and 1514, inclusive.

The wildcardUserOffset, wildcardOffset pair must conform to one of the following four relationships and also be subject to the range restrictions listed above. For n = 0,..,378

Offset 4n 4n 4n 4n+2 UserOffset 4n 4n+1 4n+2 4n+3

As an example, consider four examples in the following table for locating the filter at or near the beginning of a packet:

- 6 filter/mask bytes - - desired - 0 1 2 3 4 5 6 - position - A|f/m0 f/m1 f/m2 f/m3 00 00 00 |0,4,8,12,... B| 00 f/m0 f/m1 f/m2 f/m3 00 00 |1,5,9,13,... C| 00 00 f/m0 f/m1 f/m2 f/m3 00 |2,6,10,14,... D| 00 00 00 f/m0 f/m1 f/m2 f/m3|3,7,11,15,...

Example A corresponds to a UserOffset/Offset pair such as 0/0 (4n/4n). Example B represents a pair such as 0/1 (4n/4n+1). Example C is 0/2 (4n/4n+2). Finally, example D is 2/3 (4n+2/4n+3).

If any of the above constraints is not honored, the SET Response will indicate genErr.