Overview:
The ICMP Echo operation measures end-to-end response time between a Cisco router and any devices using IP
Study Notes:
- The ICMP Echo operation measures end-to-end response time between a Cisco router and a device using IP
- ICMP Echo is useful for troubleshooting network connectivity issues
- An IP SLA (Service Level Agreement) is configured on the source router
- The ICMP echo-based IP SLA detects packet loss when no ICMP echo responses are received
- Response time is computed by measuring the time taken between sending an ICMP Echo request message to the destination and receiving an ICMP Echo reply
- Response time is round-trip time (RTT) regardless of the number of hops between source and destination
- The IP SLA source router sends an ICMP echo packet to a specific destination at the configured time and frequency
- The SLA may be configure with a timeout value, which specifies the amount of time the source will wait for a response from the destination
- The SLA may be configured with a threshold value, which is used to set the number of missed responses before the SLA is considered to be violated
- The SLA may be configured with history settings to specify how the statistics from previous ICMP responses are maintained
- The ICMP Echo operation can be displayed and analyzed to determine how the network IP connections are performing
Configuration
config t ip sla <operation-number> icmp-echo <destination-ip-address> source-ip <source-ip-address> history buckets-kept <size> history filter failures frequency <seconds> history hours-of-statistics-kept <hours> history lives-kept <lives> history statistics-distribution-interval <milliseconds> threshold <milliseconds> timeout <milliseconds>
Schedule the SLA
ip sla schedule 1 life forever start-time now
Troubleshooting Tips
- If the IP Service Level Agreements (SLAs) operation is not running and not generating statistics, add the verify-data command to the configuration (while configuring in IP SLA configuration mode) to enable data verification
- When data verification is enabled, each operation response is checked for corruption. Use the verify-data command with caution during normal operations because it generates unnecessary overhead
- Use the debug ip sla trace and debug ip sla error commands to help troubleshoot issues with a IP SLA operations