IP SLA config and static route tracking

Technology: Routing
Area: Static Routes
Title: IP SLA config and static route tracking
Vendor: Cisco
Software: 12.X , 15.X, IP Services
Platform: Catalyst 3560, 3700, 3800, 4500, 6500,6800, ISR Routers, ASR Routers

IP SLA config sets up IP SLA (Service Level Agreement Monitor) as active monitoring feature which allows to determine connectivity in two ways. Firstly, by checking IP destination availability. Secondly, by measuring specific parameters of the network along the given path. IP SLA config is commonly used for performance statistics like Delay, Jitter or Packet Loss in SP and Enterprise environments. However here you can see the example of achieving the WAN redundancy in the easy way (i.e. without dynamic routing protocol implementation) using IP SLA.

Define the ip SLA, protocol type, destination and source:

Router(config)#ip sla 1
Router(config-ip-sla)#icmp-echo 10.10.10.1 source-interface FastEthernet1/0

Probing parametrs :


Router(config-ip-sla-echo)#timeout 2000
Router(config-ip-sla-echo)#frequency 5
Router(config-ip-sla-echo)#threshold 250

Run the probing:


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

Define tracking that will result with TRUE or FALSE depending on IP SLA status:
Router(config)#track 10 ip sla 1 reachability

Bidning the track to static route:
Router(config)#ip route 0.0.0.0 0.0.0.0 10.10.10.1 track 10

Configuring the alternate route in case of primary is removed by track result:
Router(config)#ip route 0.0.0.0 0.0.0.0 10.10.10.2 5

Track command next to particular route determines the route presence in routing table. If there is no echo response according to given parameters (IP SLA) the track statement takes the FLASE value and the route is removed from routing table leaving the lasting static route that uses another next hop thus assuring redundancy.