I have intensively worked in this area for the last three years. I could say that there are three ways of inter/intra-chip communication, namely, multilevel bus, serial link, and parallel link.

The multilevel bus (shared bus) is simply several channels in parallel for data and another separated channel for clock (e.g. 8 channels for data and additional one for clock). This is a very old way of data communication and has several drawbacks specially when it's used with more than couples of modules.

As the NoC normally contains few hundreds of modules, it is almost impossible to use the shared bus with this large number of required channels. So we have to use either parallel or serial point-to-point link (without any channel sharing between the modules).

which one is better serial link or parallel ?? there is no absolute answer. it mainly depends on the channel length and the technology node.

However with the advancement in the technology, serial link has shown a potential in being the preferred. as it consists of a single channel which transfer both clock and data. The later initially is for instance eight channels in parallel but get squeezed (compressed by a faster clock ) and serialized into single stream then transferred to the destination. at this stage it is converted back to eight channels. So it is able to transfer the same amount of data as the the shared bus but with much less area utilization as it only need one channel and with much faster speed.

for more info you can follow my publications or "Design and modeling of low-power clockless serial link for data communication systems"

thank you Mohammed Alser sir :)

Please give some more detail about multilevel bus architecture with an example.

Thanks

NoC is scalable and extensible.

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