The NoC is capable of handling AXI4-Stream connections and supports N:M configurations.
The intended use case for the N:M configuration is a cross-connect. Using the TDEST field, masters can dynamically direct their output to a given slave, such as in a video switching application.
In cases where multiple masters direct their output to a particular slave (N:1), the NoC arbitrates in a first-come, first served manner. If you require a different or more well-defined arbitration scheme you need to create your own multiplexer and routing algorithm.
In cases where a master broadcasts to multiple slaves (1:M), it is expected that the slaves do not appreciably back-pressure the master. Having one slave apply backpressure for more than a few cycles might stall the master and impact the other slaves.