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Highlighted
Beginner

Cisco Tracking issue IP SLA mon

Hello, 

 

Just looking for a little advise.

 

Basiclly we have a router with two circuits on it.

 

The idea is that when one fails it will push over to the other and vice versa.

 

We already have tracking in place for some routes on a circuit, but they want some appliccations going over the other.

 

So the issue I have is i have placed tracking on the routes and within ip sla mon but it only goes over the backup circuit (1.102) the primary is 1.113.

 

So what i Did was the below:

 

ip sla monitor 3

 type echo protocol ipIcmpEcho 171.17.36.148 source-interface FastEthernet0/1.113

 timeout 400

 threshold 200

 frequency 15

ip sla monitor schedule 3 life forever start-time now

 

track 30 rtr 3 reachability

 

along with routes

 

 ip route 171.17.36.148 255.255.255.255 192.168.10.156 track 30

 ip route 171.17.36.148 255.255.255.255 192.168.10.36 10

 

Whatever address has the track next to it does not work and will only go to the other and will not failover when you shut down the circuit in question.

 

Not overly sure what im missing so any help or pointers would be appreciated

9 REPLIES 9
Highlighted
VIP Mentor

Re: Cisco Tracking issue IP SLA mon

Hello,

 

try and use the config below:

 

ip sla 1
icmp-echo 171.17.36.148 source-interface FastEthernet0/1.113
timeout 400
threshold 200
frequency 15
!
ip sla schedule 1 life forever start-time now
!
track 1 rtr 1 reachability
!
ip route 171.17.36.148 255.255.255.255 192.168.10.156 track 1
ip route 171.17.36.148 255.255.255.255 192.168.10.36 10

Highlighted
Beginner

Re: Cisco Tracking issue IP SLA mon

Hello, 


So ip sla instead of the monitor part?

Highlighted
VIP Mentor

Re: Cisco Tracking issue IP SLA mon

Exactly. Does the proposed config work ?

Highlighted
Beginner

Re: Cisco Tracking issue IP SLA mon

Havent tried it as yet, other ones are all ip sla monitor as opposed to anything else which work correctly.

 

I will try and implement this tomorrow and see if there is any change on how it reacts

Highlighted
Beginner

Re: Cisco Tracking issue IP SLA mon

Hello, 

 

the IOS only allows ip sla monitor....

 

when tracking is removed I am able to route and ping to the required IP host, but not when tracking is enabled

Highlighted
Beginner

Re: Cisco Tracking issue IP SLA mon

Hello,

 

That is because you are monitoring 171.17.36.148 which is reachable through both links. The following thing happens: When link 1 which is tracked goes down 171.17.36.148 is unreachable and the track is down removing the static route, when the link 2 route is installed 171.17.36.148 becomes again reachable and track is up installing again link 1 route and 171.17.36.148 is again unreachable, and thus you have ping-pong between the routes. Try using another destination to montior reachable only through the main link which is tracked. Then you would be certain that link 1 is down and it is reasonable to move to link 2, and when the host monitored is up the track is also up and link 1 is installed again.

Highlighted
Beginner

Re: Cisco Tracking issue IP SLA mon

Thanks for the response.

 

The issue is they are using this as a backup solution so the address will be valid on both links as it needs to reach them both.

Highlighted
Beginner

Re: Cisco Tracking issue IP SLA mon

No problem, just use another host reachable only through main link. Make another static route pointing to this other host through the main link, and replace the ip you are using with the ip of this other.

Take this example, maybe it is easy to speak about connection to the internet.

i have 2 default routes:

ip route 0.0.0.0 0.0.0.0 gi1 gateway-a - ProvierA

ip route 0.0.0.0 0.0.0.0 gi2 gateway-b 10 -ProviderB

google dns server is reachable through both, but I want to reach it only through gateway-a.

i make another static route: ip route 8.8.8.8 255.255.255.255 gi1 gateway-a

so i can monitor 8.8.8.8 being shore that if ping works ProviderA works, if ping doesnt work ProviderA is down.

i make:

ip sla monitor1
ping 8.8.8.8 sourge gi1
...ialaialaiala

track 1 ip sla 1 reachability

- apply track to gi1 

ip route 0.0.0.0 0.0.0.0 gi1 gateway-a track 1

 

you can replace 0.0.0.0 with any other destination, but you cant monitor a host accesible through both links. make a static route to that host only through a single link.

Highlighted
Beginner

Re: Cisco Tracking issue IP SLA mon

Hello, 

 

the IOS only allows ip sla monitor....

 

when tracking is removed I am able to route and ping to the required IP host, but not when tracking is enabled