Cisco CRS-1 System Description page 39

Switch Fabric
This chapter describes the Cisco CRS 4-slot line card chassis switch fabric and switch fabric card (SFC).
The following sections are included:
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•
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Switch Fabric Overview
The switch fabric is the core of the Cisco CRS 4-slot line card chassis. The switch fabric is implemented
through switch fabric cards 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 an MSC and performs
the switching necessary to route the data to the appropriate egress MSC.
The switch fabric is divided into four planes (plane 0 to plane 3) that are used to evenly distribute traffic
across the switch fabric. Each switch fabric plane is independent and is 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.)
There are two types of switch fabric cards used in the line card chassis: QQ123 (40G fabric) and
QQ123-140G (140G fabric). Each fabric card implements all three stages of the switch fabric.
Figure 4-1
fabric. Note that the figure shows all three stages of the switch fabric provided by the fabric cards in the
line card chassis.
Figure 4-1
IP
Data
OL-10805-10
Switch Fabric Overview, page 4-1
Switch Fabric Operation, page 4-2
Switch Fabric Cards, page 4-3
shows the basic path of IP data packets through the Cisco CRS 4-slot line card chassis switch
Basic 4-Slot Line Card Chassis Switch Fabric
PLIM MSC
Ingress
Cisco CRS Carrier Routing System 4-Slot Line Card Chassis System Description
C H A P T E R
Switch fabric
S1 S2 S3
4
MSC PLIM
IP
Egress
Data
4-1