âWires-onlyâ VDSL2 Modem Test Plan - NICC
âWires-onlyâ VDSL2 Modem Test Plan - NICC
âWires-onlyâ VDSL2 Modem Test Plan - NICC
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18<br />
<strong>NICC</strong> ND 1436 V1.1.2 (2013-09)<br />
A.3 Vectoring<br />
Compliance shall be determined by the following test :<br />
Vectored<br />
DSLAM<br />
48 interferers<br />
16<br />
Vectored<br />
CPE<br />
32 interferers<br />
16<br />
Vectored<br />
CPE<br />
16 interferers<br />
16<br />
Vectored<br />
CPE<br />
PC<br />
200m 300m 400m<br />
500m<br />
900m<br />
Figure A.3 : <strong>Test</strong> Configuration for Checking Vectoring<br />
Configure the DSLAM with an operator-specific <strong>VDSL2</strong> profile.<br />
The vectoring test configuration shown in Figure A.3 comprises three lengths of TP-100 100-pair<br />
cable (200m, 300m and 400m 1 ) which are connected in series to form a 500m length (i.e. 200m +<br />
300m) and a 900m length (i.e. 200m + 300m + 400m) of cable 1,2 .<br />
16 vectored CPE modems are located 200m from the DSLAM, another 16 vectored CPE modems<br />
are located 500m from the DSLAM and a final 16 vectored CPE modems are located 900m from<br />
the DSLAM. The same cable segments are used to construct the 200m, 500m and 900m lengths.<br />
This means that there are 48 (i.e. 3 x 16) interferers present in the 200m length, 32 (2 x 16)<br />
interferers in the 300m length and 16 interferers in the 400m length.<br />
1) Capture the performance data of the 48 CPE modems both with vectoring disabled and with<br />
vectoring enabled. This enables the performance to be benchmarked.<br />
2) Replace one of the modems located 200m from the DSLAM with the CPE under test.<br />
3) Measure the non-vectored performance and then the vectored performance (assuming that<br />
the CPE supports vectoring).<br />
4) Repeat for 500m and 900m cable lengths.<br />
5) Compare the results obtained using the CPE at each cable length against those obtained<br />
using the 48 vectored CPE. Note whether the CPE under test supports vectoring and whether<br />
there is any significant drop in performance either to the modem or the rest of the vector group<br />
when vectoring is enabled<br />
Expected Outcome – “Pass” if the CPE modem is capable of supporting vectoring and does not<br />
adversely affect the performance of the vector group, “Fail” if not.<br />
1 These loops are selected as being representative of typical lengths encountered in the UK access network. Other lengths can be substituted.<br />
2 Alternatively a suitable crosstalk emulator & loop simulator for vectored <strong>VDSL2</strong> can be substituted.<br />
<strong>NICC</strong> Standards Limited
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