The switch fabric is the core of the Cisco CRS routing system. The Cisco CRS routing system fabric is implemented through multiple redundant switch fabric cards (SFCs) installed in the chassis. The switch fabric uses a cell-switched, buffered, three-stage Benes switch fabric architecture. The switch fabric receives user data from a modular services card (MSC) or Forwarding Processing card (FP) and performs the switching necessary to route the data to the appropriate egress MSC or FP.
The switch fabric is divided into eight planes (plane 0 to plane 7) that are used to evenly distribute trafficacross the switch fabric. Each switch fabric plane is independent and not synchronized with one another. Each cell traverses the switch fabric using a single switch fabric plane (cells are not bit-sliced across the switch fabric).
When operating as a single-shelf (standalone) system, the LCC uses one of the following SFCs:
- CRS-16-FC/S (40G)
- CRS-16-FC140/S (140G)
- CRS-16-FC400/S (400G)
Each SFC implements all three stages of the switch fabric. Note the following:
- The CRS-16-FC140/S fabric is able to operate in both 40G mode and 140G mode to allow interconnection between 20G, 40G, or 140G MSCs and FPs.