Cisco - Monitoring Campus Networks - IP Service Level Agreement

IP SLA Overview

  • IP Service Level Agreement (IP SLA)
  • Used to gather information on how the work is performing from a point actually within the network
  • Takes the place of remote probes, all managed from central location
  • Legacy names
    • Response Time Reporter (RTR)
    • Service Assurance Agent (SAA)
  • Basic tests only require the source device to be configured
  • Advanced tests (E.g. Jitter) need a peer device to be configured as a “Responder” in order to collec the statistics
  • Control connection is setup between source and responder to carry out
    • Test setup
    • Time stamping of packets to account for latency
  • NTP is recommended to keep clocks synchronised
  • Tests can be triggered via SNMP as long as write access is permitted

Features

  • Generate SNMP Trap when thresholds are exceeded
  • Schedule further IP SLA tests when thresholds are exceeded
  • Track IP SLA to trigger NHRP failover
  • Gather voice quality measurements frm all over the network

Supported Tests

  • ICMP-Echo
  • Path-Echo
  • Path-Jitter (requires responder)
  • DNS
  • DHCP
  • FTP
  • HTTP
  • UDP-Echo
  • UDP-Jitter (requires responder)
  • TCP-Connect

Configuring IP SLA

NOTE: In IOS prior to 12.2(33) the commands has the “ip sla monitor” prefix

Enable responder on destination

ip sla responder

Enable IP SLA Authentication

key chain <name>
  key-string <string>

ip sla key-chain <name>

Create a new test

Note: In order to modify a test the existing test must be unscheduled then deleted before being recreated

ip sla <number>
  <test-type> <parameters>
  frequency <seconds>

Schedule the test to run

ip sla schedule <number> [life {forever | <seconds>}
       [start-time {<hh>:<mm>:<ss>] [<month> <day> | <day> <month>]
       | pending | now | after <hh>:<mm>:<ss>}]
       [ageout <seconds>] [recurring]

Configure Specific Test Types

Setup An ICMP Echo Test

ip sla <number>
  icmp-echo <ip> [<src-ip>]
  frequency <seconds>

Setup UDP Jitter Test

NOTE: Ensure that IP SPA Responder is running on the remote device

ip sla <number>
  udp-jitter <dst-ip> <dst-udp-port> [source-ip <source-ip>]
             [source-port <src-port>] [num-packets <packets>]
             [interval <ms>]

ip sla <number>
  udp-jitter <dst-ip> <dst-udp-port> codec
             {g711alaw|g711ulaw|g729a}

Advanced IP SLA Usage

Enable HSRP Failover based on IP SLA Result

track <number> ip sla <sla-number> {state | reachability}

interface <name>
  standby <group> track <sla-number> decrement <value>

Verify IP SLA

Display Configuration

show ip sla configuration [<id>]

Display IP SLA Test Result

show ip sla statistics [aggregated] [<number>]