Performance+Routing+(OER)

OER provides automatic route optimization and load distribution for multiple connections between networks. It allows you to monitor IP traffic flows and define policies based on class performance.

=Phases=

The OER process is classified into 5 phases:


 * 1) Profile
 * 2) Measure
 * 3) Apply Policy
 * 4) Control
 * 5) Verify

Profile Phase
In this phase, a subset of routes in the RIB are selected for optimization. This can be done in two ways:


 * 1) OER can monitor flows to these routes and select those with the least delay or highest throughput
 * 2) A class of traffic to performance route can be manually configured

Measure Phase
In this phase, the actual performance of the select traffic is measured. This is done either actively or passively. Passive monitor is done as the traffic transits the device. This cannot be done for all traffic classes and has some hardware and software limitations.

In active measuring, fake traffic is generated that matches the selected traffic flows and that fake traffic is measured for performance.

Apply Policy Phase
Once the traffic is measured, it is compared to a set of low-high thresholds. There are two types of policies that can be defined: traffic-class and link policies. Traffic class policies are defined for prefixes or applications. Links policies are defined or entrance or exit paths at the network edge.

Control Phase
In this phase the traffic is controlled so that it conforms to network standards. This can be done by manipulating the prefix reachability. Policy based routing can also be used for this.

Verify Phase
Once control has been applied, OER verifies the traffic is taking the preferred path and conforming to network standards. If it isnt, the control policy applied is removed and the cycle loops.

=Network Components=

OER consists of two primary components: The master controller and border routers.

The master controller is a router that coordinates all OER functions within a network. It maintains communication and authenticates the sessions with the border routers. It also monitors inbound or outbound traffic flows and then applies the defined policies.

The border router is a device on the network edge, and this is where all policy changes are implemented. It helps in monitoring by reporting prefix and performance measurements to the master controller.

Configuration:

http://www.cisco.com/en/US/docs/ios-xml/ios/oer/configuration/12-4t/oer-setup-ntwrk.html