3Com LINKBUILDER MSH 4 PORT ETHERNET BRIDGE MODULE Network Hardware User Manual


 
1-28 C
HAPTER
1: I
NTRODUCTION
DUA1860-0AAA01
Bit Filtering
Bit filters
selectively filter out traffic based on bit values occurring
in the first 64 bytes of each frame. This provides extremely flexible
filtering. You can test any combination of bits within a six-byte
long field falling within the first 64 bytes of the frame and
beginning on a byte boundary. You can have up to five input
filters and five output filters.
When you set up a bit filter, you define a
bit pattern
. The bit
pattern consists of up to 48 bit values (1 or 0), for example,
10111001. The bridge compares this pattern against the pattern
found in a specified location for every packet. If the patterns
match, the bridge filters or forwards the packet as specified by
additional filter information.