Cisco IP SLA ICMP Echo Example

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This is how I setup an ICMP-echo IP SLA on my Cisco Router to monitor when my internet goes out. If it goes down, I re-route traffic (I’ve excluded this part of the config). When it comes back up, I set the routing/NATing back to the original state (again, excluded from this post).
IP SLA Configuration:

ip sla 10
 ! Connection Monitor
 icmp-echo 8.8.8.8 source-interface GigabitEthernet0/0
 frequency 10
ip sla schedule 10 life forever start-time now

Configure Cisco Embedded Event Manager (EEM) to handle an UP or DOWN state of SLA 10:

event manager applet primary_circuit_down
 event track 10 state down
 action 1.0 syslog msg "Primary Circuit is DOWN"
 ! You can insert other commands here to do something useful...
event manager applet main_circuit_up
 event track 10 state up
 action 1.0 syslog msg "Primary Circuit Appears UP"
 ! You can insert other commands here to do something useful...

This is the SLA configuration overview:

ciscorouter#sh ip sla conf
IP SLAs Infrastructure Engine-III
Entry number: 10 (Primary Circuit Monitor)
Owner:
Tag:
Operation timeout (milliseconds): 5000
Type of operation to perform: icmp-echo
Target address/Source interface: 8.8.8.8/GigabitEthernet0/0
Type Of Service parameter: 0x0
Request size (ARR data portion): 28
Verify data: No
Vrf Name:
Schedule:
   Operation frequency (seconds): 10  (not considered if randomly scheduled)
   Next Scheduled Start Time: Start Time already passed
   Group Scheduled : FALSE
   Randomly Scheduled : FALSE
   Life (seconds): Forever
   Entry Ageout (seconds): never
   Recurring (Starting Everyday): FALSE
   Status of entry (SNMP RowStatus): Active
Threshold (milliseconds): 5000
Distribution Statistics:
   Number of statistic hours kept: 2
   Number of statistic distribution buckets kept: 1
   Statistic distribution interval (milliseconds): 20
Enhanced History:
History Statistics:
   Number of history Lives kept: 0
   Number of history Buckets kept: 15
   History Filter Type: None

Statistics of the IP SLA:

ciscorouter#sh ip sla stat
IPSLAs Latest Operation Statistics
IPSLA operation id: 10
        Latest RTT: 32 milliseconds
Latest operation start time: 17:42:41 EDT Fri Mar 30 2012
Latest operation return code: OK
Number of successes: 103
Number of failures: 0
Operation time to live: Forever

#cisco, #snmp