OC3port Plus
Users Manual
5-20
Coset Polynomial Option
The OC3port Plus has a coset polynomial (X
6
+X
4
+X
2
+ 1) option, which is used to
verify the incoming header checksum.
One of the chief benefits of using this option is that you can improve the efficiency
of the cell delineation process and facilitate the recovery of the frame structure,
thereby reducing the likelihood of signal loss errors.
Whether you choose to use the coset polynomial or not depends on your particular
application. Most ATM equipment supports the coset polynomial, but some
equipment does not. If you set this option to OFF on the tester and the equipment
supports the coset polynomial, it can cause interoperability problems. It is best to
check and then make sure that both sides (the OC3port Plus and the equipment)
have the same setting.
To enable or disable the
Coset Polynomial
option, do the following:
1.
Press the
ATM
key. The
ATM SELECTIONS
menu is displayed.
2.
Press the
Down Arrow
key to move
ATM Options
to the selection line. Press
ENTER
. The
ATM OPTIONS
submenu is displayed.
3.
Press the
Down Arrow
key to move the
Coset Polynomial
option to the selection
line, as in:
ATM OPTIONS:
Payload Scrblng ON
Coset Polynmial ON
Correction Algr OFF
za073f.eps
This option has two settings:
ON
and
OFF
.
When set to
ON
(the default), the OC3port Plus adds the coset polynomial to
the HEC.
When set to
OFF
, the OC3port Plus does not add the coset polynomial to the
HEC.
4.
Press the
Left
or
Right Arrow
key to select the desired setting.
The change takes effect immediately. The setting you selected is now the
current value of the
Coset Polyn0mial
option.
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