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Question: in computer networks, circuit switching guarantees the arriving order while packet switching does not, is it the same case here? Is there kind of virtual circuit approach applies here?


@yingchai I think that it should still apply for the "network-on-chip" network. If you consider the case where a certain path has high contention and 1 packet is waiting for another packet to be sent due to buffering of packets, and another packet (with the same source and destination as the first) gets sent but the path for this packet has less contention. This second packet can definitely reach the destination before the first.


In circuit switching, sending a message requires establishing a connection to the destination, upon which to send the entire message in full; During this transaction, the resources that comprise the connection remain dedicated to it, meaning that no other data can use them and all pieces of data follow a fixed, unchanging path.

In circuit switching, quality and reliability are guaranteed: no pieces of data will fail to arrive, and no sharing of resources means that one can expect full bandwidth to be dedicated to the transaction. Also, since the path is predetermined beforehand, less transfer time is used than packet switching. However, this method does not use bandwidth efficiently, as no other transactions can use resources until the given one completes.

In packet switching, the data is broken up in the small parts which are sent, irrespective of one another, through the network; these packets independently seek out the shortest path on the fly as circuits become available. Once all packets have reached their destination, they are reassembled according to the original data order (each packet contains a header that denotes its original order and how many packets comprise the original data).

Packet switching makes the most efficient use of bandwidth: Unlike in circuit switching, where the path is laid out prior to data transfer, packets can set and revise the most efficient path as resources become available. In addition, sending data does not require waiting until a direct path is available. Packet switching also tends to scale better, as there is little overhead or unnecessary seizure of resources. However, packet loss can hinder efficiency, and reliable transfer requires more elaborate protocols than circuit switching.