Send probe out to the network to measure network performance
Can influence routing decisions base on delay.
Measure Network Performance
Verify first:
Perform a traceroute in R5 going to host 50.0.0.100 and check if the ping will go through ISP1. R1 ping to 50.0.0.100 should go over ISP2.
Configuration:
Mirror the configuration to R3 and R1 then verify and compare the result
#sh ip sla statistic
# sh ip sla summary
##Ave Jitter time should not go over 150ms
##Check MOS value
Influence Routing Decisions (measure RTT Delay / latency)
Example:
We need to send Data to 50.0.0.100 (from R5) but let say ISP1 path is
becoming congested, We can inform our Router to route that traffic to other
way if the delay is too much.
STEP 1
Let set a threshold value (ms). If exceed, take alternate route
R5
Router(config)#ip sla 2
Router(config-ip-sla)#icmp-echo 60.0.0.2 source-ip 192.168.1.3
Router(config-ip-sla-echo)#frequency 5
Router(config-ip-sla-echo)#threshold 100
Router(config-ip-sla-echo)#exit
Router(config)#ip sla schedule 2 start-time now life forever
STEP 2
Associate IP SLA with Tracking Object
Tracking Object = Keep an eye on something & give us a state of UP or DOWN.
If exceed threshold turn DOWN if not stay in UP
R5
Router(config)#track 2 ip sla 2
Router(config-track)#delay down 10 up 10 # Make sure things are good for 10 seconds
STEP 3
Lets set a condition just like this.
If TRACKING OBJECT == Up State:
Next-hop = 60.0.0.2
Else:
Next-hop = 192.168.1.2
#Floating Static route to 50.0.0.100/32
Router(config)#ip route 50.0.0.100 255.255.255.255 60.0.0.2 1 track 2
Router(config)#ip route 50.0.0.100 255.255.255.255 192.168.1.2 2