I am trying to understand the command "ip sla responder udp-echo ipaddress a.b.c.d port xx" but I have a doubt, the ip address (a.b.c.d) in the command refers to the local IP address on the device where it is being configured or it is the IP address that belongs to the device where the udp packets are being sent.
For example, I have 2 routers A and B connected and with EIGRP so they both know each other's networks, on router A I have a loopback 192.168.0.1 and on router B the loopback 192.168.0.2.
In the router A I configured IP SLA
ip sla 1
udp-echo 192.168.0.2 5000 source-ip 192.168.0.1 control disable
ip sla schedule 1 life forever start-time now
On router B I want to configure ip sla responder udp-echo, the question is what IP should I put in the command "ip sla responder udp-echo ipaddress a.b.c.d port xx".
Is it the loopback IP of router A that is sending the packets (192.168.0.1) or is it the loopback IP of router B that is receiving the packets (192.168.0.2), I have already read information on the subject but I am confused. I did the simulation of this example and if I use the IP that receives the packets 192.168.0.2 the number of successful packets increases but if I use the IP 192.168.0.1 the number of failed packets increases.
I hope you can help me to understand this topic, I just want to confirm what is the correct use of the command ip sla responder udp-echo ipaddress a.b.c.d port xx".