One of the annoyances of working with OER (Optimized Edge Routing) in labs is that it is based on timers for different actions. This can be very annoying when you are doing labs since it means you will be staring for minutes (or hours) at your console screen waiting for OER to take any action.
We can however optimize the OER timers to make it learn and react faster, in this lesson I want to give you an overview of the timers we can change.
First of all you might want to consider changing the load interval of your external interfaces on the border routers. By default the load interval is calculated each 5 minutes which is an eternity when you are doing labs. We can change this to a minimum of 30 seconds like this:
BR(config)#interface serial 0/0 BR(config-if)#load-interval 30
30 seconds is the lowest value we can use, configure it using the load-interval command.
The next step is to take a look at the actual OER timers. For the learning process there are two important timers:
The learning process for OER has a periodic-interval and a monitor-period. The periodic-interval is a sleep timer that tells OER how often to start the learning process and how to long to sleep and retain the information that it has learned. By default this is 2 hours which is way too long for a lab. If you keep it at the default you might find yourself restarting the OER master cotroller more often than you wish for.
The monitor-period defines how long we will learn the different traffic flows. By default this is 5 minutes but we can reduce it. Simply said…OER will learn for a period and then go back to sleep, wake up after a while to learn again and so on. This is how we can change these timers:
MC(config)#oer master MC(config-oer-mc)#learn MC(config-oer-mc-learn)#periodic-interval 1 MC(config-oer-mc-learn)#monitor-period 1
I will set both timers to 1 minute. This makes it suitable for a lab.
There are two more OER timers that you should adjust:
The backoff timer tells OER that once a traffic flow is out of policy, the master controller will wait for a certain amount of time before it tries to find another exit path. This backoff timer tells the master conroller how long to wait and it increases each time the master controller is unable to find an optimal exit path. We use this backoff timer so the master controller gets more time to find an exit path after each time it is unsuccessful.