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This field defines the bits in the received frame, starting at the specified
offset
, that should be tested against the contents of the
value
field. Only
the bits which have a value of B′1′ in the mask will be tested.
•
Logical Operator
The following operators can be used for testing:
− Equal
− Not_equal
− Less_than
− Greater_than
•
Value
This field specifies the 32-bit unsigned value against which the contents
of a frame starting at the specified
offset
should be compared.
When you install the Multiprotocol Interconnect module (or after a cold start),
the custom filter test table has 64 dummy entries defined for it. To define a
test, select the
Modify Entry
parameter on this panel. A pop up window will
be displayed, which allows you to define the parameters described above.
Once the entry is defined, select
Set Entry
to confirm or
Cancel
to abandon
the operation. An example of a Custom Filter Test Table entry is shown in
Table 39.
This example enables the Multiprotocol Interconnect module to test the
contents of two bytes, starting at offset 12 from the beginning of the MAC
address against the value X′5DC′ (1500 decimal). In Ethernet frames, this is
called the ″length″ or ″type″ field. In Ethernet V2 frames, this field always
contains a value higher than 1500, whereas 802.3 frames always contain a
value less than 1500. Therefore, this entry allows you to check and see if the
frame is an 802.3 or Ethernet V2 frame.
2. Once you have defined all the desired tests, you must define the tests that
should be performed on each port, using the
Custom Filter Statement Table
.
Note that there is one Custom Filter Statement Table for each port.
To define entries in the Custom Filter Statement Table, select Custom Filter
Statement Table from the
Bridge menu
. An example of this table is shown in
Figure 159 on page 277.
Table 39. Custom Filter Test Table
ID Test
Name
Filter
Start
Offset Mask Operator Value
1 802.3 MAC 12 FFFF0000 < 05DC
276 8260 Multiprotocol Intelligent Switching Hub