A system, a shelf, and a high density platform optimize physical arrangement of cards to maximize cooling effectiveness and line card pitch while minimizing backplane trace lengths between line interface and switch fabric cards. The shelf and system and associated card arrangement supports scaling to a larger, double size system that maintains the required length of backplane traces for card communications without compromising card cooling. Advantageously, the shelf and system maintains full NEBS compliance through an arrangement supporting full air intake/outtake through a front and/or back of the shelf or system, i.e. no side ventilation, and includes a false front to ensure all cards (switch fabric and line interface cards) are substantially flush with one another.