https://www.soclib.fr/trac/dev/wiki/Component/VciAnocANOC stands for Asynchronous Network-on-Chip (NoC) and has been developed by the CEA-Leti. ANOC is a wormhole packet switching NoC. Its architecture is composed by five ports routers interconnected by bidirectional links using send/accept asynchronous handshake protocol. Thus, the ANOC protocol offers naturally a GALS architecture. As the ANOC routers are asynchronous, the entire end-to-end path traveling the packets is completely asynchronous. The ANOC topology is not reduced to regular 2D mesh. Irregular 2D mesh or 2D torus topology can also be implemented as ANOC uses a source routing algorithm. Moreover, source routing can be used to minimize the congestion on some links, and thus reduce the packet latency. A flit is the smallest flow control unit of the network. Each flit contains two control bits, Begin of Packet (BOP) and End of Packet (EOP). BOP is set on the head flit, and EOP is set on the tail flit. Furthermore, the first flit of the packet contains the routing information and the router uses this “path-to-target” to decide the correct routing destination. The routing information is enclosed on 18-bits and two bits encodes each routing hop, which allows addressing a path of at most 9 router hops. Tags: gals, noc
|