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Choosing WAN Equipment 49
Obviously, all the possibilities for a central site router cannot be discussed at this time. There
are too many variables (and the exam doesn't even touch on all of them anyway). However, you
should know that many mid- to high-range routers, including WAN access and Access server
routers, support multiple technologies and port densities for the central site router.
In this chapter we discuss the 36X0, 4000, AS5X00, and 7200 series routers. Keep in mind that
there are high-end routers, such as the 7500 series, 12000 series, and so on. However, these
high-powered routers are beyond our scope at the moment.
3600 Router Series
The 3600 series is a versatile family of routers; for variations of supported technologies, it is
hard to beat. It is a multifunctional platform that enables routing of data, voice, video, and dial
access capabilities in a single chassis.
The 3600 series offers three chassis variants: 3620, 3640, and the new 3660. The 3620 has two
module slots, the 3640 has four module slots, and the 3660 has six module slots. Each module
slot can contain MICA modems for dial-in access, voice network modules for telephone
connectivity directly to the router, and data network modules.
The beauty of this series is that all these technologies can be implemented simultaneously in
one chassis. All the interface components can be removed, serviced, and inserted without taking
the chassis out of the rack. In addition, all the modules use spring screws that won't detach from
the component, so there is no more looking for that dropped screw.
NOTE
The modules for this router are not hot-swappable! You must turn off the power before inserting
or removing any component.
The 3620 probably is not the best choice for a central installation. Although it is a highly
versatile and capable router, it simply doesn't have the port density necessary for deploying a
wide spectrum of technologies simultaneously.
The 3640 and 3660 shine in their support of the varying technologies and speeds in the typical
Enterprise deployment. These two models combine mix and match capabilities with the
horsepower necessary to support a wide array of variables. For instance, these two routers can
provide dial-up access (through MICA modem modules), ISDN, Frame Relay, and X.25
services in a single chassis. In any central site deployment, this type of flexibility is imperative.