Optimized Edge Routing/Performance Routing

In a nutshell, Optimized Edge Routing(OER)/Performance Routing(PfR) enables dynamic routing of traffic into or out of an enterprise based on various metrics including interface counters, throughput, delay, etc. I find it interesting Cisco wants to now call it PfR but all of the IOS commands are still OER....and this folks, is why IOS can be confusing as all hell. 

OER has five phases, Profile Phase, Measure Phase, Apply Policy Phase, Control Phase and Verify Phase. OER deployments include a Master Controller (MC) and the Border Routers (BR). 95% of your configuration happens on the MC. The BR reports metrics to the MC, which processes the statistics and enforces the policies at the BR. At least one external interface must be present on each BR and a group of BRs should have at least two external interfaces.

During the Profile Phase, traffic is discovered , OER learns traffic flows that experience issues automatically. You can also configure traffic classes manually. 

During OER measure phase, measurements can be passive or active. Passive measurements include items such as interface counters and netflow data. Active measurements include border routers simulating traffic using IP SLA to discover performance characteristics. 

In setting up OER, a very important and sometimes forgetten task is to setup a local interface on the border routers that communicate with the master. In most labs I see, the MC and BR within OER are setup with the loopback addresses. This obviously make's things easier. Also, when setting up the internal/external interfaces, all interfaces are defined.

oer master

border 150.1.4.4 key oer

interface f0/0 external

interface s0/0.1 internal

interface s1/2 internal

To setup a BR...

oer border

master 150.1.5.5 key oer

local lo0

To enable automatic learning of the prefix traffic classes using netflow, issue the following on the MC:

oer master

learn

throughput

The number of learned flows could exceed the MTC capacity. This is why prefix aggregation is enabled by default (/24) and resulting metrics are summarized or averaged. You can also use BGP aggregation, non-bgp (static routes) and manually configured prefix-length.

To configure a prefix traffic class, first create a prefix-list matching the prefix.

ip prefix-list OER permit 112.0.0.0/24

Then, create an oer map.

oer-map OER 10

match ip add prefix OER

You can also 'set' policies/monitoring within the OER map.

Then apply the oer map to the master.

oer master

policy-rules OER

To enable specific protocols/ports, simply use the 'protocol' keyword from within the MC Learn prompt.

oer master

learn

protocol tcp port 80 src

To test your OER deployment, you can utilize IP SLA, and this is where my dynamips problems started. You may experience some latency and dropped pings so make sure you set your frequency and timeouts appropriately. Also, to test file transfers, make sure your routers have enough disk space (disk0=256 in Dynagen .net configuration file). I wasn't able to transfer an IOS image to my routers so instead I used a very large text file. I used a Terminal Server with an ethernet interface pointed to a loopback adapter on my PC to send the text file to the router's flash.

I'm not going to cover the Apply, Control and Verify phases. I had way too many problems using dynamips on my work laptop and spent way too much time troubleshooting instead of labbing. I did make it through the lab. This is my third time through an OER lab and I am feeling pretty comfortable.

If anyone has any specific questions regarding OER, I would be happy to hear them. I will try to answer them intelligently.