🎯 IP SLA Tracking Services

Master Network Monitoring & Failover on Cisco IOS

14% Complete

🎉 Welcome to IP SLA Tracking Services Lab!

In this hands-on lab, you'll master Cisco's IP Service Level Agreement (SLA) technology to monitor network performance and implement intelligent failover mechanisms.

📚 What You'll Learn

  • Configure IP SLA operations for ICMP echo (ping) monitoring
  • Set up IP SLA tracking objects for route manipulation
  • Implement automatic failover using tracked static routes
  • Monitor jitter, packet loss, and latency metrics
  • Configure HTTP and DNS SLA operations
  • Troubleshoot common IP SLA issues
  • Verify SLA operations and tracking states

💡 Why IP SLA Matters

IP SLA transforms your network from reactive to proactive by continuously monitoring critical paths and services. It enables automatic failover, ensures SLA compliance, and provides real-time visibility into network performance.

🏗️ Lab Environment

You'll work with a dual-ISP scenario where IP SLA monitors primary and backup links, automatically failing over when the primary path degrades or fails.

Ready to begin? Click on the Topology tab to see the network design!

🗺️ Network Topology

                     Internet
                    ╱        ╲
                   ╱          ╲
            ISP1 (Primary)   ISP2 (Backup)
            203.0.113.1      198.51.100.1
                 │                │
            Gi0/0│           Gi0/1│
                 │                │
            ┌────┴────────────────┴────┐
            │                          │
            │      Edge Router         │
            │     (IP SLA Source)      │
            │                          │
            │   Track 1 → ISP1 Path    │
            │   Track 2 → ISP2 Path    │
            │                          │
            └──────────┬───────────────┘
                       │Gi0/2
                       │10.0.0.1/24
                       │
                ┌──────┴──────┐
                │   LAN Switch │
                └──────┬──────┘
                       │
                   LAN Clients
                   10.0.0.0/24

📊 IP Addressing Scheme

  • ISP1 (Primary): 203.0.113.0/30
  • ISP2 (Backup): 198.51.100.0/30
  • LAN Network: 10.0.0.0/24
  • DNS Target: 8.8.8.8 (Google DNS)
  • HTTP Target: www.cisco.com

🎯 Design Goals

This topology implements automatic failover between ISP links using IP SLA tracking. The primary path through ISP1 is monitored continuously, with traffic automatically redirecting to ISP2 if the primary fails.

📋 Prerequisites & Planning

1

Hardware Requirements

  • Cisco ISR Router (2900/4000 series recommended)
  • IOS version 15.0 or higher
  • Minimum 256MB RAM
  • At least 2 WAN interfaces
2

Software & Licensing

  • IP SLA feature set (included in most IOS images)
  • DATA or SEC license for advanced SLA operations
  • Terminal emulator (PuTTY, SecureCRT, or Terminal)
  • TFTP/FTP server for config backup (optional)
3

Pre-Configuration Checklist

! Verify IP SLA capability show ip sla application ! Check available memory show memory statistics ! Verify interface status show ip interface brief ! Save current configuration copy running-config startup-config
⚠️ Important: Always backup your configuration before implementing IP SLA. Misconfigured tracking can cause routing loops or connectivity loss.

💡 Planning Best Practice

Document your IP SLA thresholds based on baseline measurements. Monitor your network for 24-48 hours to establish normal latency, jitter, and packet loss values before setting SLA parameters.

⚙️ Step-by-Step Configuration

Router#
1

Configure Basic ICMP Echo SLA

! Enter IP SLA configuration ip sla 1 icmp-echo 8.8.8.8 source-interface GigabitEthernet0/0 frequency 10 timeout 5000 threshold 3000 ! ! Schedule the SLA operation ip sla schedule 1 life forever start-time now

This creates an ICMP echo operation that pings Google DNS every 10 seconds through the primary ISP interface.

2

Create Tracking Object

! Configure tracking object for SLA 1 track 1 ip sla 1 reachability delay down 10 up 5 ! ! Optional: Set tracking description track 1 description Primary_ISP_Tracking
⚠️ Delay Timers: The delay prevents flapping. Down delay = 10 seconds before marking as failed. Up delay = 5 seconds before marking as restored.
3

Configure Tracked Static Routes

! Primary route with tracking ip route 0.0.0.0 0.0.0.0 203.0.113.1 track 1 ! Backup route with higher administrative distance ip route 0.0.0.0 0.0.0.0 198.51.100.1 10

The primary route is removed from the routing table when track 1 fails, allowing the backup route to take over.

4

Advanced: HTTP SLA Operation

! Configure HTTP GET operation ip sla 2 http get http://www.cisco.com frequency 60 timeout 10000 ! ip sla schedule 2 life forever start-time now ! Track HTTP availability track 2 ip sla 2 reachability
5

Configure Jitter Operation

! Configure UDP jitter for VoIP monitoring ip sla 3 udp-jitter 203.0.113.1 5000 source-ip 203.0.113.2 frequency 30 request-data-size 172 tos 184 ! ip sla schedule 3 life forever start-time now
✅ VoIP Monitoring: This operation measures jitter, latency, and packet loss - critical metrics for voice quality.

💡 Configuration Best Practice

Start with ICMP echo operations for basic connectivity monitoring. Once stable, add HTTP or DNS operations for application-level monitoring. Use jitter operations only when monitoring real-time traffic like VoIP or video.

🔧 Troubleshooting Guide

1

SLA Operation Not Starting

Error: %IP_SLA-4-OPERNOTSTARTED: IP SLAs operation 1 not started
! Check SLA configuration show ip sla configuration 1 ! Verify scheduling show ip sla schedule ! Force restart no ip sla schedule 1 ip sla schedule 1 life forever start-time now
2

Tracking State Flapping

Symptom: Track state rapidly changing between Up and Down
! Increase delay timers track 1 ip sla 1 reachability delay down 30 up 30 ! Adjust SLA thresholds ip sla 1 threshold 5000 timeout 7000
3

High CPU Usage

! Check SLA process CPU usage show processes cpu | include IP SLA ! Reduce operation frequency ip sla 1 frequency 60 ! Limit concurrent operations ip sla group schedule 1 1-5 schedule-period 60 start-time now
4

No Route Failover

Issue: Track shows Down but route doesn't change
! Verify track binding show track 1 show ip route track-table ! Check route configuration show running-config | include ip route ! Debug tracking debug track debug ip routing

💡 Troubleshooting Tip

Use "debug ip sla trace" sparingly in production. It generates extensive output that can impact performance. Always use with "terminal monitor" and specific operation filters.

Common Issues Reference Table

Issue Cause Solution
Timeout failures Network latency Increase timeout value
Memory allocation error Too many operations Reduce operation count
Source interface down Interface failure Change source interface

✅ Verification Procedures

1

Verify SLA Operations

! Show all SLA operations show ip sla statistics ! Detailed statistics for operation 1 show ip sla statistics 1 details ! Expected Output: IPSLAs Latest Operation Statistics IPSLA operation id: 1 Latest RTT: 24 milliseconds Latest operation start time: 10:45:32 UTC Mon Dec 4 2023 Latest operation return code: OK Number of successes: 145 Number of failures: 2 Operation time to live: Forever
2

Verify Tracking States

! Show all tracking objects show track brief ! Detailed track information show track 1 ! Expected Output: Track 1 IP SLA 1 reachability Reachability is Up 5 changes, last change 00:45:23 Delay up 5 secs, down 10 secs Latest operation return code: OK Tracked by: Static IP Routing 0
3

Test Failover

! Simulate primary link failure interface GigabitEthernet0/0 shutdown ! Monitor route changes show ip route show track 1 ! Verify traffic uses backup traceroute 8.8.8.8 ! Restore primary link interface GigabitEthernet0/0 no shutdown
✅ Success Criteria: Traffic should switch to backup route within 10 seconds of primary failure and restore within 5 seconds of recovery.
4

Performance Metrics

! Show jitter statistics show ip sla statistics 3 ! Monitor real-time show ip sla statistics aggregated ! Historical data show ip sla history 1

✅ Verification Checklist

  • ☐ All SLA operations show "OK" return code
  • ☐ Tracking objects correctly bound to routes
  • ☐ Failover occurs within configured delay timers
  • ☐ No packet loss during failover (< 3 packets)
  • ☐ CPU usage remains below 50%
  • ☐ Memory utilization stable
  • ☐ Syslog shows tracking state changes

📝 Knowledge Check

1. What is the default frequency for an IP SLA ICMP echo operation?
2. Which command schedules an IP SLA operation to run indefinitely?
3. What does the 'delay down 10 up 5' command configure in tracking?
4. Which IP SLA operation type is best for monitoring VoIP quality?
5. What happens to a tracked static route when the tracking object goes down?
6. Which show command displays the current state of all tracking objects?