Configuring Cisco IP SLA

Cisco IOS IP SLA (Service Level Agreement) is a tool that can be used to generate synthetic network traffic used for network management.  SLA can be configured to send dhcp, dns, ICMP, frame-relay, ftp, http, jitter, pathEcho, pathJitter, TCP connects, UDP Echo and voip packets.  These packets can be used to measure metrics to ensure you are getting the performance you expect.

One of the simplest, yet most valuable, SLA configurations is ICMP.  Cisco SLA can be configured to send ICMP packets to a remote device to ensure you are getting an appropriate latency across a link.  For our example this is exactly what we will be looking at.


Topology

CISCO IP SLA

Configuration Steps:

 1) Create SLA Session
 2) Define SLA Traffic Type
 3) Define SLA destination.
 4) Configure SLA frequency.
 5) Configure SLA Schedule
 6) Review Configuration
 7) Monitor Statistics

R1(config)#ip sla monitor 1

With the above command we configure an SLA session number of “1”.

R1(config-sla-monitor)#type echo protocol ipicmpEcho 1.1.1.2 source-interface serial 1/0

Above we define that we want to use icmp-echo traffic type and our destination is 1.1.1.1 with source interface as serial 1/0

R1(config-sla-monitor-echo)#frequency 5

Here we define the frequency, in seconds, of 5.  This means that ICMP echo packets will be sent every 5 seconds to 1.1.1.2

R1(config)#ip sla monitor schedule 1 life forever start-time now

With this command we set the schedule for the SLA monitor to use.  We have specified that the schedule for SLA 1 should run for a lifetime of forever and should start immediately, “now”.

R1#show ip sla monitor configuration 1
SA Agent, Infrastructure Engine-II
Entry number: 1
Owner:
Tag:
Type of operation to perform: echo
Target address: 1.1.1.2
Source Interface: Serial1/0
Request size (ARR data portion): 28
Operation timeout (milliseconds): 5000
Type Of Service parameters: 0x0
Verify data: No
Operation frequency (seconds): 5
Next Scheduled Start Time: Start Time already passed
Group Scheduled : FALSE
Life (seconds): Forever
Entry Ageout (seconds): never
Recurring (Starting Everyday): FALSE
Status of entry (SNMP RowStatus): Active
Threshold (milliseconds): 5000
Number of statistic hours kept: 2
Number of statistic distribution buckets kept: 1
Statistic distribution interval (milliseconds): 20
Number of history Lives kept: 0
Number of history Buckets kept: 15
History Filter Type: None
Enhanced History:

Above we are able to review our configuration for the SLA monitor 1.

R1#show ip sla monitor statistics
Round trip time (RTT)   Index 1
        Latest RTT: 20 ms
Latest operation start time: *23:12:50.503 UTC Tue Feb 5 2013
Latest operation return code: OK
Number of successes: 180
Number of failures: 0
Operation time to live: Forever

Here we can see the information we can hold over our ISP’s head. We can see that we have send 180 ICMP packets and they have been successful, we have had no failures and our latest RTT was 20 ms.

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