In methods and apparatus for acquiring VPN reachability information at a node of a data network, a VPN reachability information request is transmitted from a requesting node. The stack has at least a lower electronic module connected via flipchip connections to a central area of a rewiring substrate. Furthermore, the capacitance multiplier is implemented with a plurality of multiplying paths to reduce effects of noise for more stable generation of the multiplied capacitance. The static classifier is searched only if a dynamic classifier key for the frame is not found, or the dynamic key actions indicated that the static classifier should also be searched. The mismatch noise shaper selectively overrides the quantizer when the quantizer output has prevented the mismatch noise shaper from controlling selection of elements at the mismatch noise shaper output for a predetermined time period.