Cisco IP SLA: NoConnection/Busy/Timeout

Hi.

I'm running second-hand 3925E and have another issue (on 15.7.3). This time it's related to IP SLA.

Check the related config :

ip sla 1 icmp-echo 8.8.8.8 source-interface GigabitEthernet0/3 timeout 6000 frequency 10 ip sla 2 dns www.google.com name-server 8.8.8.8 source-ip 1.2.3.5 source-port 1024 timeout 6000 frequency 10 track 10 ip sla NUMBER reachability delay down 5 up 5 ip sla schedule NUMBER life forever start-time now route-map ISP2 permit 10 match ip address 40 match interface GigabitEthernet0/2 route-map ISP1 permit 10 match ip address 40 match interface GigabitEthernet0/3 access-list 40 permit 192.168.0.0 0.0.255.255 ip nat inside source route-map ISP1 interface GigabitEthernet0/3 overload ip nat inside source route-map ISP2 interface GigabitEthernet0/2 overload ip route 0.0.0.0 0.0.0.0 GigabitEthernet0/3 1.2.3.4 track 10 ip route 0.0.0.0 0.0.0.0 GigabitEthernet0/2 5.6.7.8 5 

Now to the issue. I'm testing the functionality by issuing shutdown/no shutdown commands on both primary (GE0/3) and backup (GE0/2) WAN interfaces. Procedure:

• shutdown of GE0/3. After 6 seconds, default route is replaced by the backup one. Everything works fine;

• no shutdown of GE0/3. Backup route isn't removed from the routing table. I get the following results after issuing show ip sla statistics:

i

IPSLA operation id: 1 Latest RTT: NoConnection/Busy/Timeout Latest operation start time: 18:48:38 GMT+1_DST Wed Sep 19 2018 Latest operation return code: Timeout Number of successes: 151 Number of failures: 143 Operation time to live: Forever IPSLA operation id: 2 Latest RTT: NoConnection/Busy/Timeout Latest operation start time: 18:48:39 GMT+1_DST Wed Sep 19 2018 Latest operation return code: Timeout Number of successes: 101 Number of failures: 136 Operation time to live: Forever 

I think "ip sla 2" worked for 1 or 2 toggles, while "ip sla 1" fails immediately after toggling the interface.

Of course, before switching interfaces on and off, both IP SLAs report correct stats.

Now, I've seen BUG1, BUG2 and some older ones but it looks like 15.7 should not be affected.

Any idea what to do now?

EDIT1: Typos, formatting fixed