Modular Interfaces

The modular-interface remote access products provide the designer with a few benefits, including
an upgrade path and, typically, higher densities that are unavailable in the fixed-interface
models. This flexibility comes at a price; however, and the costs associated with the removal and
replacement of network equipment easily offsets this initial cost difference.
The benefits of the modular router also lead to potential savings in the initial acquisition of
the device. Sometimes the fixed-interface router provides interfaces that are not needed—Cisco
still charges for the unused ports. Although port disparity is uncommon given the wide array of
fixed-configuration routers in the Cisco product line, it is possible to find situations in which a
high number of Ethernet ports also require a high number of serial ports on a fixed router,
which greatly adds to the cost. Modular routers provide the following positives and negatives:
Again, it’s usually best to select modular routers to avoid forklift upgrades in the future—
ones that require the complete replacement of the chassis. However, the use of modular routers
comes at higher initial and support costs.

Pros Cons
Defined upgrade path Higher cost
Potentially lower total cost of ownership More complex installation
More difficult and costly to stock spare
equipment