High-speed routing constraints and algorithmshandle differential pairs, net scheduling,timing, crosstalk, layer set routing,and the special geometry requirementsdemanded by today’s high-speed circuits.The autorouting algorithms intelligentlyhandle routing around or through vias,and automatically conform to definedlength or timing criteria. Automatic netshielding is used to reduce noise on noisesensitivenets. Separate design rules maybe applied to different regions of thedesign