Interrouter Signals

summary of traditional NoC interrouter signals

summary of SMART interrouter signals

flit_valid and flit_value denote the valid flag and the flit content, respectively.

lookahead_route carries the route information for lookahead routing.

flit_vc_id is no longer needed.

This is because, in SMART, a VC is selected upon a head flit’s arrival instead of before the arrival ???此处不太明白。

vnet_id: In order to decide whether it can allow flit bypass, an SSR recipient router needs the virtual network ID to check whether its immediate downstream router has a VC available in the virtual network.

inject_router_id: If a head flit was allowed to bypass while a body/tail flit was prematurely stopped (due to allocation failure or lack of VC), the router at which the body/tail flit stops should include the original source router (injector) ID in the SSR. Otherwise, downstream routers cannot determine which VC the body/tail flit should use or release.

head_flit_flag: A head flit can bypass an SSR recipient router only if the immediate downstream router has a free VC. This flag is used for this check. This check is not needed for body and tail flits.