I'm studying for my BSCI and trying to get to grips with EIGRP Stuck in Active. I understand the theory (I think) and according to the book "Cisco Press BSCI Third Edition" if you have a remote site with a FS pointing back to the core then an SIA condition will occur. I wanted to see this with my own eyes and so built a lab reflecting the books topology on page 122 (I used 1 remote site (R3) instead of 3). Yet when I disable a route (18.104.22.168) that route doesn't go SIA, it works immediatly, SIAQueries or SIA replies aren't even being used.
I've attached a drawing of the topology along with capture of "debug ip eigrp packets" and all router and L3 switch configs.
R3 is the remote site, SW2 and SW3 are in the data centre.
I've changed the bandwidth and delay on the links between the data centre and the remote site so the FS is chosen correctly.
On the attached drawing I've tried to visual each step, from query to reply along all the paths in sequence as they occur using EIGRP sequence numbers. I've not added the "received" packets apart from the first one in the sequence.
What I don't understand is how can SW2 send a reply (Step 15) about a route that's active and awaiting a reply from R3? According to the book it states that no route can send a query down the interface on which it received the query, yet this is exactly whats heppening at step 12.
Am I looking at this backward or something? I've used the sequence numbers to make sure the steps are in sequence but yet it just doesn't make sense to me.
Has Cisco used some new functionailty in EIGRP that has made it to the latest version of code?
on R3 I'm using c2600-adventerprisek9-mz.124-15.T8.bin
on SW2 I'm using c3560-ipservicesk9-mz.122-50.SE3.bin
On SW3 I'm using c3550-ipbasek9-mz.122-44.SE2.bin