What is crosstalk and how is it mitigated in VLSI?

Crosstalk is unwanted coupling between adjacent signals via capacitance. Effects: Crosstalk delay (aggressor switching affects victim timing), Crosstalk noise (glitch on victim), and Functional failures. Analysis categorizes aggressor-victim pairs and checks timing impact and noise immunity. Mitigation: Increase spacing (routing rules for critical nets), Use shielding (grounded wires between sensitive signals), Minimize parallel run length, NDR (non-default routing rules) for critical nets, and Buffer insertion (reduce transition times). SI-aware routing and timing tools consider crosstalk during optimization.