he fabric modules for the 7000s are installed in the rear. The connectors for all these modules are in the middle of the switch-hence midplane. Nexus 7000s are designed to minimize failure points. As you can see in Figure 18-2, there are three power supplies, five fabric modules, two fabric fan trays, and two system fan trays. With dual supervisors, these switches are pretty well suited for a high- availability network. ===== Airflow output Cable management System fan trays Fabric fan trays Slots 1-4: Modules Slots 5-6: Supervisors Slots 7-10: Modules Fabric modules Airflow intake Power supplies Figure 18-2. Nexus 7010 front and back; images courtesy of Cisco Systems, Inc.; unauthorized use not permitted It may seem odd to have the fabric modules separate when we made such a big deal out of them being included in the 6500 supervisors. On the 6500, there were only two fabric modules (one on each supervisor). On the 7010, we can have five. Why is this important? Because each fabric module adds switching capacity, and with five slots, Nexus Hardware they can offer N+1 redundancy. That means that although we need only four, we can have five installed SO that if one fails, there is no outage or degradation in capacity. Additionally, we can upgrade the capacity of the switch by adding more powerful fabric modules without having to shut down the switch. In a true high-availability network, this type of architecture is a must. Phone guys have been laughing at us for years because while networking equipment rarely incorporated these features, phone systems have used them for decades. Nexus 5000 There are three Nexus 5000 switches available at this time. They are the 5010, 5020, and the 5548. The 5010 is a one-rack-unit (1 RU) switch with twenty 10 Gbps ports and a single expansion port. The 5020 is a 2 RU switch with forty 10 Gbps ports and two expansion ports. The 5548 is a 1 RU switch with thirty-two 10 Gbps ports and one expansion port. The expansion ports on the 5010 and 5020 are the same, while the 5549 expansion por