Intermec MobileLAN 21 Series, Системное руководство

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MobileLAN access 21XX System Manual
3-22
The next table explains each parameter.
Parameter Explanation
ExprSeq
(Expression
Sequence) Chains expressions together for filtering. After you change the
parameter, the statements are reordered and renumbered so the
Expression Sequence order is maintained. The range is from 0 to 255.
This parameter works with the Action parameter; for example, if the
action is set to And, then the next sequence in another expression is
processed.
Offset Identifies a point inside a bracket where testing for the expression is to
start. The range is from 0 to 65535.
Mask Applies a data pattern to the packet. If the data pattern in the mask
matches the packet, then the specific action is performed. The mask
indicates the bits that are significant at the specified offset. A bit is
significant if a bit in the mask is set to one. If this field is empty, the
length of the field is determined by the longest value in the Filter
Values menu for the specified value ID. The mask values are entered in
hexadecimal pairs. You can enter 0 to 8 pairs.
Op (Operation) Performs a logical operation when a data pattern matches a value in the
Filter Values menu to determine if the specified action should be taken.
Valid operations include:
•
EQ (equal)
•
NE (not equal)
•
GT (greater than)
•
LT (less than or equal)
Value ID Represents a value in the Filter Values menu. The bytes after the packet
offset are compared to the data pattern indicated by the value. Value ID
can be from 0 to 255 and must match one or more value IDs in the
Filter Values menu.
Action Sets the action to Pass, Drop, or And. If you set the action to And, the
filter expression with the next highest sequence is applied.