332
Network-on-Chip
≈ 20 μm
≈ 5 m m
≈ 10 mm
Figure 11.7
A 3D 2 × 4 × 4 Mesh-1 network.
layer are few micrometers long, whereas between the two adjacent layers,
the links are 20 μm long. Here, mesh topology having a single core attached
to each router is termed as Mesh-1 network, whereas that having two cores
attached to each router is termed as Mesh-2 network.
A BFT-based NoC with four cores attached in each leaf level router is shown
in Figure 11.9. The BFT-based network connecting 32 cores also has three types
of routers: (1) leaf having node degree 6, (2) stem having node degree 6, and (3)
root having node degree 2. The routing decisions are taken by leaf and stem
routers, whereas the root router is replaced by a FIFO and is used to pipeline
the links. In 2D NoC implementation, as shown in Chapter 4, the length of the
longest wire of the BFT-based network is min (l 1 ,l 2 )/ 2 , where l 1 and l 2 are