HP ProLiant BL620c HP BladeSystem c-Class architecture - Page 7

Scalable interconnect form factors The interconnect bays also scale in a single-wide/double-wide form factor for efficient use of space and improved performance. A single interconnect bay can accommodate two single-wide interconnect modules in a scale-out configuration or a larger, higher-bandwidth double-wide interconnect module (Figure 5). Figure 5. Single-wide/double-wide interconnect form factor Single-wide interconnect modules Double-wide interconnect modules Two midplane connectors on the same PCB The scalable interconnect form factor provides similar advantages as the scalable device bays:  Supports the maximum number of interconnect modules  Allows enough space in the double-wide module to include two signal connectors on the same PCB plane, providing reliable and simple connectivity to the NonStop signal midplane Star topology The device bays and interconnect bays connect in a fan-out, or star, topology centered around the interconnect modules. The exact topology depends on your configuration and the enclosure. For example, if you place two single-wide interconnect modules side-by-side (Figure 6a), the architecture is a dual-star topology: Each blade has redundant connections to the two interconnect modules. If you use a double-wide interconnect module, then it is a single star topology, providing more bandwidth to each of the server blades. Figure 6b shows the redundant configuration using double-wide interconnect modules. 7