What kind of DSL line will affect vectoring performance significantly at a site?

Question

Options

• AA vectoring ADSL2+
• BA vectoring VDSL2
• CA non-vectoring ADSL2+
• DA non-vectoring VDSL2

• A
  11% (4)
• B
  6% (2)
• C
  3% (1)
• D
  80% (28)

Explanation

Option D is correct because vectoring is a crosstalk-cancellation technology designed specifically for VDSL2, which operates at high frequencies where crosstalk between cable pairs is severe. A non-vectoring VDSL2 line in the same bundle creates exactly the kind of high-frequency interference that vectoring is built to eliminate - but since it doesn't participate in the vectoring group, its crosstalk cannot be calculated and cancelled, degrading performance for all other vectored lines in the bundle.

Why the distractors are wrong:

• A (vectoring ADSL2+): Vectoring is a VDSL2 standard; ADSL2+ does not support it, so "vectoring ADSL2+" doesn't exist as a meaningful line type.
• B (vectoring VDSL2): A vectoring VDSL2 line participates in the crosstalk-cancellation group, so it cooperates with the system rather than disrupting it.
• C (non-vectoring ADSL2+): ADSL2+ uses lower frequency bands with far less crosstalk overlap into VDSL2's frequency range, so its impact on vectoring performance is minimal compared to a non-cooperating VDSL2 line.

Memory tip: Think of vectoring as a choir that cancels noise by singing in sync. A non-vectoring VDSL2 line is a loud singer in the same vocal range who refuses to join - ruining the harmony. ADSL2+ is a different instrument entirely and causes far less disruption.

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