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IP SLA Questions

November 1st, 2018 Go to comments

Quick IP SLA Overview:

IP SLA is an active method of monitoring and reliably reporting on network performance. The word “active” here means it generates and monitors traffic continuously across the network actively. With IP SLAs, routers and switches perform periodic measurements. Using IP SLAs can provide these benefits:
+ Service-level agreement monitoring, measurement, and verification.
+ Network performance monitoring
 – Measures the jitter, latency, or packet loss in the network.
 – Provides continuous, reliable, and predictable measurements.
+ Edge-to-edge network availability monitoring
+ Troubleshooting of network operation

IP SLAs collects a unique subset of these performance metrics:

+ Delay (both round-trip and one-way)
+ Jitter (directional)
+ Packet loss (directional)
+ Packet sequencing (packet ordering)
+ Path (per hop)
+ Connectivity (directional)
+ Server or website download time

Question 1

Question 2

Explanation

The ICMP Echo operation measures end-to-end response time between a Cisco router and any devices using IP. 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. Many customers use IP SLAs ICMP-based operations, in-house ping testing, or ping-based dedicated probes for response time measurements.

Reference: http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipsla/configuration/15-mt/sla-15-mt-book/sla_icmp_echo.html

Question 3

Explanation

The Internet Control Message Protocol (ICMP) Echo operation measures the end-to-end response time between two devices that use IPv4. The 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.

An IP SLA can be used to performs network performance monitoring, including measure the latency, packet loss, jitter and response time in the network. The example below shows how to configure an IP SLA ICMP Echo (send an ICMP request to 192.168.1.254 every 300 second with a timeout of 500ms):

Device(config)#ip sla 1

Device(config-ip-sla)#icmp-echo 192.168.1.254
Device(config-ip-sla-echo)#frequency 300 //send an ICMP
Device(config-ip-sla-echo)#timeout 500
Device(config-ip-sla-echo)#exit
Device(config)#ip sla schedule 1 start-time now

Question 4

Explanation

The ICMP Echo operation measures end-to-end response time between a Cisco router and any devices using IP. 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. Many customers use IP SLAs ICMP-based operations, in-house ping testing, or ping-based dedicated probes for response time measurements.

Reference: http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipsla/configuration/15-mt/sla-15-mt-book/sla_icmp_echo.html

Question 5

Question 6

Question 7

Explanation

To measure end-to-end response time we have to use ICMP echo to continuously ping to a remote device. The difference between ICMP path echo and ICMP echo is the former can measure hop-by-hop response time on its whole path while the latter can only measure to a specific destination.

Question 8

Explanation

Verifying IP SLAs Operations
Perform this task to display and interpret the results of an IP SLAs operation. Check the output for fields that correspond to the criteria in your service level agreement to determine whether the service metrics are acceptable.
SUMMARY STEPS
1. enable
2. show ip sla statistics

Reference: https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipsla/configuration/15-mt/sla-15-mt-book/sla-any-percent.html

Verifying IP SLAs UDP Jitter Operations
SUMMARY STEPS
1. enable
2. show ip sla configuration
3. show ip sla group schedule
4. show ip sla statistics
5. show ip sla statistics 2 details

Reference: https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipsla/configuration/15-mt/sla-15-mt-book/sla_udp_jitter.html#task_49723D1D58A249DDAEF50E40059622BE

Note: You can find most of the “show ip sla …” command explanations and sample outputs at: https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipsla/command/sla-cr-book/sla_s1.html

Comments (1) Comments
  1. Leo
    January 10th, 2020

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