This is the per-path retransmission ceiling - how many times SCTP will retry sending DATA chunks to this specific destination address before marking that path inactive - with 5 attempts as the RFC-recommended default, distinct from the association-wide cSctpAssocMaxRetr. It's the threshold that actually triggers a multihoming failover to a backup address, so lowering it makes the association fail over to a backup path faster at the cost of being less tolerant of a few dropped packets. A latency-sensitive voice signaling deployment might lower this to 3 specifically on the primary path to trigger failover to the backup address sooner after real trouble starts.