PM73487 datasheet(21/251 Pages) PMC

21 / 251 page

PM73487 QRT

PMC-Sierra, Inc.

PMC-980618

Issue 3

622 Mbps ATM Traffic Management Device

Released

Datasheet

1.6

5 Gbps to 160 Gbps Application Example – LAN-to-WAN

A powerful application of the QRT and the 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 popu-

lating the additional switch card with port cards as needed (in increments of 622 Mbps). With this

switch fabric topology, scaling is possible 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 almost constant

Figure 9. 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

PM73487 Datasheet(PDF) 21 Page - PMC-Sierra, Inc