
PMC-Sierra, Inc.
PM73488 QSE
L
PMC-980616
Issue 3
5 Gbit/s ATMSwitch Fabric Element
Released
Datasheet
20
1.5
A powerful application of the QRT and QSE devices is the creation of modules that can be used in a range of
switches with only the interconnection changing between different sizes. ATM switches from 5 Gbps to 160 Gbps
can be realized with only two unique cards. A port card has one QRT, and a switch card has two QSEs. The switch
fabric consists of three stages, each with 32 QSEs (or 16 switch cards). To plan for future scalability, the middle stage
must be built-in upfront. This is a one-time cost. Then, in order to scale in 5 Gbps increments, one switch card and its
accompanying eight port cards should be added. Finer bandwidth scaling is possible by populating the additional
switch card with port cards as needed (in increments of 622 Mbps). With this switch fabric topology, scaling is possi-
ble up to 160 Gbps. Once the initial middle stage cost has been incurred, the per-port cost for 5 Gbps through
160 Gbps systems remains constant
5 Gbps to 160 Gbps Application Example – LAN-to-WAN
Figure 8. 5 Gbps to 160 Gbps Switches Modeled Using Only Two Cards
QRT
(PM73487)
Port Card - One QRT
One UTOPIA
Level 2 Interface
Switch Card - Two QSEs
QSE
(PM73488)
QSE
(PM73488)
x32
x32
x32
x32