EIGRP - SIA Process and RTP retry attempts

EIGRP uses the Reliable Transport Protocol (RTP) to send EIGRP messages reliably, which requires acknowledgments for reliable delivery. RTP may retry failed attempts up to 16 times before EIGRP considers a neighbor unreachable.

Conversely, EIGRP's Stuck in Active (SIA) process uses timers to function.

It is important to note that the RTP retry process runs concurrently and independently of the SIA process. In fact, the 16 retries of RTP operate at the Transport layer (i.e. within the RTP protocol) while the SIA process operates at the Application layer (i.e. within EIGRP itself).

Because of the large difference between the RTO and the SIA timer, it is almost certain that the 16 retries have already been attempted well before any SIA query is sent.

Links

https://networklessons.com/eigrp/eigrp-queries-and-stuck-in-active