f blade servers that reside in a chassis. These chassis-based servers usually allow aggregation of networking links into multiple 10 Gb links. This may lower the number of ports required for your network, though you'll need to provision properly with 10 Gb-capable network devices. Additionally, virtual servers have become very popular. Combined with blade servers, the IP requirements can be staggering. With physical network interfaces replaced by virtual devices (within virtual servers), it's very tempting for server admins to just add another NIC to a server where they might not with traditional hardware. When de- signing for these new server architectures, remember that they will likely need 10 Gb ports, usually configured as trunks. To get the most from your links, consider multi- chassis link aggregation such as VSS or Nexus vPC. Watch your QoS, too, as some blade server chassis "carve up" bandwidth without using QoS. Small Networks Many small companies don't need elaborate three-tiered networks. Maybe they have only one office, or even three, but the offices are small and the networks are simple. Even some larger companies do not have elaborate networks. No matter the size or complexity of the network, every aspect of it should be thoroughly documented. Chapter 35: Designing Networks CHAPTER 36 IP Design When a network or group of networks is designed well, the payoff can be substantial. The payoff, however, is in hours not spent, which can be very hard to quantify. Believe me, though-designing IP space the right way the first time can save literally thousands of work hours over the lifetime of the network. IP address allocation is rarely done properly, and many unlucky network administrators end up inheriting a mess of IP networks that's just been thrown together over time. In many cases, small networks are built with no vision of where the companies might end up, resulting in massive undertakings when the IP networks need to be changed. And even the best of IP address schemes can be rent asunder by a merge