This is the number of inbound SCTP streams negotiated for this association during setup, determining how many independent, parallel delivery sequences the peer can use to send data without one stream's ordering requirements blocking another's. It matters for applications that use multiple streams to avoid head-of-line blocking, such as separating different message types onto different streams so a delayed message on one stream doesn't stall unrelated ones. An M3UA signaling association might negotiate a modest number of streams like 2, while a bulk multiplexed data application could negotiate dozens to maximize parallelism.