IP SLA - Monitor the Network Performance

Probably most typical usage of IP SLA is to measure the and UDP Jitter and Echo, to make sure that the path is good enough to send the sensitive VoIP traffic. Two sides need to be configured, CLIENT and SERVER (RESPONDER).
IP SLA can be configured without configuring a specific PROBE, just configure sending a generated packet to the  RESPONDER, where the RESPONDER is configured to respond with a TIME STAMP information, so the source can calculate the performance values. CAREFULL with the times, configure NTP if you're not certain the devices are synced.

To configure the RESPONDER with the IP and PORT of the RESPONDER:
(config)#ip sla  monitor responder

Make sure you configure the CLIENT device in accordance with these defined parameters:
(config)#ip sla monitor 10
(config-sla-monitor)#type udpEcho dest-ipaddr 10.187.122.2 dest-port 500
(config-sla-monitor-udp)#frequency 5 <- IN SECONDS
(config-sla-monitor-udp)#hours-of-statistics-kept 1 <-HOW MUCH TIME THE STATISCICS ARE KEPT
(config-sla-monitor-udp)#request-data-size 1500 <- PACKET SIZE

And then just START the IP SLA on the CLIENT (in this case starts immediately and lasts for 100 seconds only):
(config)#ip sla monitor schedule 10 start-time now life 100

Check the statistics:
#sh ip sla moni statistics
Round trip time (RTT)   Index 10
        Latest RTT: 2 ms <- THIS IS WHAT YOU WANT TO KNOW, ROUND TRIP TIME (RTT)
Latest operation start time: *14:47:06.923 UTC Fri Dec 6 2013
Latest operation return code: OK
Number of successes: 10
Number of failures: 0
Operation time to live: 52 sec

And on the RESPONDER:
#sh ip sla monit responder
IP SLA Monitor Responder is: Enabled
Number of control message received: 17 Number of errors: 0
Recent sources:
    10.187.122.1 [14:25:11.241 UTC Fri Dec 6 2013]
    10.187.122.1 [14:25:06.241 UTC Fri Dec 6 2013]
    10.187.122.1 [14:25:01.237 UTC Fri Dec 6 2013]
    10.187.122.1 [14:24:56.237 UTC Fri Dec 6 2013]
    10.187.122.1 [14:24:51.237 UTC Fri Dec 6 2013]

If you are using IP SLA for ROUTING, meaning - you want to TRACK a certain route using ICMP (ping), and depending on the result - "tune" the routing table, you have 2 options:

OPTION 1: Use a TRACK object and attach it to the STATIC ROUTE:
(config)#track 10 ip route 10.1.12.0 255.255.255.0 reachability
(config)#ip route 1.0.0.0 255.0.0.0 10.1.12.2 track 10

Check the status of the TRACK 10 object, and based on that - you can know if your STATIC route is UP:
#sh track 10
Track 10
  IP route 10.1.12.0 255.255.255.0 reachability
  Reachability is Up (connected)
    3 changes, last change 00:04:04
  First-hop interface is Serial0/1/0
  Tracked by:
    STATIC-IP-ROUTING 0

IMPORTANT: Make sure that the prefix you are tracking isn't available using some other protocol, like OSPF:
#sh track 10
Track 10
  IP route 10.1.12.0 255.255.255.0 reachability
  Reachability is Up (OSPF) <- THIS IS NOT WHAT WE WANTED TO ACHIEVE HERE
    3 changes, last change 00:03:59
  First-hop interface is FastEthernet0/0
  Tracked by:
    STATIC-IP-ROUTING 0

OPTION 2: Use the IP SLA ICMP ECHO (ipIcmpEcho) to monitor end-to-end response

STEP 1: DEFINE THE IP SLA OBJECT
(config)#ip sla monitor 10
(config-sla-monitor)#$type echo protocol ipIcmpEcho 10.1.12.2 source-ipaddr 10.1.12.1
(config-sla-monitor-echo)#frequency 5

STEP 2: DONT FORGET TO LAUNCH THE IP SLA:
(config)#ip sla monitor schedule 10 start-time now life forever

STEP 3: DEFINE THE TRACK Object using the defined IP SLA:
(config)#track 15 rtr 10 reachability <- 15 is RTR NUMBER, 10 is the IP SLA we're attaching

*Make sure the TRACK is UP before you attach it to the route:
#sh track 15
Track 15
  Response Time Reporter 10 reachability
  Reachability is Up
    2 changes, last change 00:00:18
  Latest operation return code: OK
  Latest RTT (millisecs) 36
  Tracked by:
    STATIC-IP-ROUTING 0

STEP 4: Attach the TRACK OBJECT to the STATIC ROUTE, like in the option 1:
(config)#ip route 1.0.0.0 255.0.0.0 10.1.12.2 track 15

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