Figure 6 shows the per node saturation throughput for different size 2D grids and Clos networks under random traffic as a function of the packet length. The Clos shows better per node performance, this is because of the higher cross-sectional bandwidth. The effect of packet length on throughput can also be seen, for small packets the throughput is reduced due to fixed packet overheads. Medium sized packets give the best performance because of the buffering present in the STC104, each switch can buffer 32 bytes in both the link input and output ports. Long packets fill the entire path from source to destination, and therefore throughput is reduced by head-of-line blocking.