BRX-VDSL2 User Guide
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180-0153-001-R02
subscribers with pair bonding) from the recommended location. This is useful to determine
the Customer Serving Area (CSA) for a given access speed tier.
Please feel free to request a copy of our BRX-VDSL2 Calculator User Guide (180-0171-001) for any
assistance with using this tool.
3.5
Miscellaneous Other Placement Guidelines
3.5.1 Bonded Pairs
For convenience, the BRX-VDSL2 Calculator does include an option (checkbox) for pair bonding.
This feature assumes that the two loops are essentially identical and therefore doubles the resulting
bandwidth for both downstream and upstream. In reality, bonded pairs are often not the same length.
It is recommended to enter the longest loop in the calculator in order to optimize placement for this
loop. Since the other loop is shorter, the resulting bandwidth resulting from the bonded pairs should
be slightly better than what the Calculator will predict.
3.5.2 Vectoring and VDSL2 Profile Selection
The BRX-VDSL2 devices fully support vectoring. They also support the following VDSL2 profiles:
17a, 8a, 8b and 8d. When using the BRX-VDSL2 calculator, you should make sure to set the
vectoring and profile values that match the DSLAM settings for more accurate calculations.
3.5.3 Actual Raw Throughput is Different from Predicted Values
There will be times when actual raw throughput will be significantly different (>10%) from predicted
values from the Calculator. This may be caused by a number of factors. One of the most likely
reason is that the Target SNR default value in the BRX-VDSL2 Calculator (default set to 8 dB), is not
the same as the one provisioned in the DSLAM. If that is the case, change the value in the Target
SNR box to match the DSLAM setting. If this does not resolve the issue, then it may be because you
are faced with “less than ideal” line conditions where the bandwidth is negatively impacted by bridge
taps, influence from power lines and/or disturbances from other pairs or the use of other protocols in
the same binder such as T1/E1, HDSL, and G.SHDSL. As a result, it is difficult to predict what the
expected bandwidth will be but we recommend that you still follow the optimal placement
recommended by the BRX-VDSL2 Calculator for the actual loop length and gauge.
Note
: In order to predict the expected bandwidth as accurately as possible, it is recommended to use
the
“Optimized Bandwidth Analysis” button in the lower right corner of the Calculator and increase the
loop length (and recalculate) until the
“Raw Downstream Bandwidth” in column 4 is equal to what you
are measuring. Once that is achieved, the amount indicated in column 6 entitled
“With BRX-VDSL2
Downstream Bandwidth” should be a good estimate of what you can obtain.
Note:
please refer to the BRX-VDSL2 Calculator User Guide (180-0171-001) for more details.
