Agilent Technologies 622Vu Advisor, User Manual

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For each bit position, specify one of the values below, combining the 1s and 0s
into hexadecimal characters for purposes of data entry (e.g., entering four 1s as a
single hex F). Use hexadecimal if the Options menu Show Header Values in
Decimal Format setting is OFF; decimal if it is ON:
Bit (s)
Setting
Tells 622Vu Advisor…
0 (zero) Ignore this bit position; it’s not relevant to the filter.
1 Examine this bit position. Store the cell in this filterset if all positions corre-
sponding to 1s in the mask contain the values (0 or 1) specified in the same bit
positions in a filter entry.
X Ignore all the bits in this field. If you use Xs in a field, the entire field must specify
Xs.
By default (i.e., if you’re not using advanced masking), 622Vu Advisor looks at
the first 28 bit positions of each header (the GFC, VPI, and VCI fields). With
advanced masking, it examines the first 48 bits (also the PTI, CLP, HEC, and
first byte of the payload).
Change the mask as necessary, to
indicate those bit positions you want
to examine (mask value is 1), and
those you want to ignore (mask
value is 0). In the example shown to the right (and the corresponding bit mask
shown below), we’re asking 622Vu Advisor to look at the 1-bit CLP:
FilterSet
Mask
Bit:
Byte 5 Byte 1 Byte 2 Byte 3 Byte 4
8 7 6 5 4 3 2 1 8 7 6 5 4 3 2 1 8 7 6 5 4 3 2 1 8 7 6 5 4 3 2 1 8 7 6 5 4 3 2 1
Payload Byte 1
8 7 6 5 4 3 2 1
1 X X X X X X X X X X X X X X X X
X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X
HEC VCI
PTI GFC
VPI
CLP
Payload
Filter Entries in Advanced Filtering Mode
With Advanced Filtering Mode on, the filter-entry window lets you specify
selection criteria based on all the header fields, as well as the first byte position
of the payload. Any fields you’ve instructed 622Vu Advisor to ignore are grayed
out in the Filter Match area, and shouldn’t be entered.
Use the other character positions to specify bit values you want to match to
incoming cells:
8: Filtering Captures
8.6 Advanced Filtering Mode
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