Configuring Bridging 15-7Figure 15-2 Bridge MAC Filter Configuration Screen[A],[A],[E],[F],[G] from Main MenuHow Filter Masks WorkMost Bridge filter parameters are assigned values and associated "masks." The maskdetermines (by the process described below) whether the filter will be applied to thepacket.The binary bits of the mask will be "ANDed" (0+0=0, 0+1=0, 1+1=1) to the value, asin this example:Assume the value (hex) is 1234 and the mask is F000. The binary "ANDing" is asfollows:Value: 0001001000110100Mask: 1111000000000000AND Result: 0001000000000000The mask will also be ANDed to its corresponding field in each Bridged packet asdetermined by Bridge Filter Applications. This result will be compared to the ANDresult of the configured value and mask. If the two results match, the filter will beapplied. This process allows a number of packet field values to match the AND resultof the mask and value; for example:Packet field = 1233, Mask = F000: Packet field = 1237, Mask = F000:Binary value: 0001001000110011 Value: 0001001000110111Mask: 1111000000000000 Mask: 1111000000000000AND Result: 0001000000000000 AND Result: 0001000000000000Nod e Name=nod e_xyzBrid ge Filter Defin itions* Filter C ategory 5–MAC* Filter I D 1A Filter N ame filter_abcB S ource MA C A ddress Value ff00ac00C S ource MA C A ddress Mask ffff0000D D es tin ation MAC Ad dres s Value 10ac45000001E D es tin ation MAC Ad dres s Mas k ffffff000000Option::
