Key Requirements of Campus Designs
The “ideal” campus network should strive to achieve certain objectives. Some of these aspects have already been mentioned, but several new and important issues are introduced here (the new points are mentioned first):
- Load balancing— Given redundant paths, load balancing allows you to utilize all of the bandwidth you paid for. As is discussed in more detail in Chapter 15, flexibility, intelligence, and ease of configuration can be critical factors when utilizing this important feature.
- Deterministic traffic patterns— Traffic that flows in predictable ways can be crucial to network performance and troubleshooting. This can be especially true during network failure and recovery situations.
- Consistent number of hops— One of the principle factors contributing to deterministic traffic flows is a consistent number of hops throughout the network. As is discussed later in the chapter, this can best be achieved through a modular and consistent design.
- Ease of configuration— The network should not be excessively difficult to initially configure.
- Ease of maintenance— Ongoing maintenance tasks should be minimized. Where required, the tasks should follow well-established patterns that allow “cookie cutter” configurations.
- Ease of troubleshooting— Some designs can appear extremely appealing on paper, but they are a nightmare to troubleshoot (for example, extremely flat networks). A good design utilizes scalable modules or building blocks to promote easy troubleshooting through consistency and predictability.
- Redundancy— A 10–20 percent increase in hardware costs can increase network reliability by several hundred percent.
- Cost— Cost per port is especially important for high-density IDF devices.