Designing Enterprise Campuses

In typical campus designs, individual buildings connect to a central building by way of physical layer uplinks. You can create uplinks using optical wavelengths, where numerous wavelengths of light create separate logical channels on single mode fiber. Optical technologies including dense wavelength division multiplexing (DWDM) and Cisco coarse wavelength division multiplexing (CWDM) have major bandwidth benefits between buildings but at a much higher cost than more traditional campus cabling designs. A possible reason for the higher cost of using DWDM or CWDM is that you require dedicated physical layer optical networking gear to multiplex the wavelengths onto the single mode fiber. Traditional physical layer uplinks include dark fiber, copper cabling, or wireless connectivity between the buildings.

You should centralize your user’s access to corporate services, WAN connectivity to branch offices, and Internet access in the main campus building. Your users can connect through access switches at Layer 2 or 3 by routing or switching traffic to the central building through distribution switches located in the individual campus buildings. To provide resiliency for user access to centralized corporate resources, you can use Spanning Tree Protocol (STP), Etherchannel, or redundant routed links between the campus backbone and distribution switches. Figure 4-2 gives a fully redundant campus network design.