Thank you Viktor for spotting this typo.
should be:
lane0 of DSP1 to lane0 of DSP2,
lane1 of DSP1 to lane0 of DSP$3$,
lane$2$ of DSP1 to lane0 of DSP4
and to be on the safe side:
lane1 of DSP2 to lane1 of DSP3,
lane 2 of DSP2 to lane 1 of DSP4,
lane 2 of DSP 3 to lane 2 of DSP4.
Alon.