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New Member

OER

Hi,

I have just bagan to deploy OER in my network, however I have some confusions. In fact there are two internet links terminating on my edge router, on which I want to configure OER (same individual router will serve as MC and border router).

Kindly answer about the following:

1. In the configuration of MC, when we define the external and internal interfaces, are these the interfaces of border router?

2. If I only configure 'throughput' under 'learn', will the router be able to select one of the two internet paths available to it based on optimal throughput?

3. Shall I keep the floating static default routes on this edge routers towards internet links? and will it select one of the two while forwarding internet traffic?

Thanks in advance for your help.

3 REPLIES
New Member

Re: OER

If my query has been overlooked, I'm requesting it again pls. Thanks.

New Member

Re: OER

Hello,

I'm trying myself to use OER.

1. In the MC configuration, internal and external interfaces are of course the one from the border(s) routers. In your case, you need to use a loopback address, since the router is the MC and the Border with the minimum 2 external interfaces..

2. The learn phase is different than the exit selection phase. So configuring just throughput in the learn config section, tells the router to learn prefixes based on the highest throuhput only... By the way except with active probing, the default probing style which is passive will only notice prefixes acting in a TCP session..

But exit selection behavior depends on the policy of MC. The MC as a default policy that you can check with a "show oer master".

By default, it will look after throughput, delay, jitter.. and will decide wich parameter prevails upon the resolves parameters : they configure wich parameter will be used first in the exit link selection.

3.

For the routing part, let your floating static routes, as OER will inject more specific route toward a particular prefix for wich OER attempt to modify routing.

exemple : the OER border reports to the MC (again itself in your case) that a better throughput is available by a different external interface (lets say int B) than the current (int A) for the prefix 1.2.3.0/24 .

So the MC will command the border (itself) to inject a route 1.2.3.0 255.255.255.0 int B in the routing table.

You can check OER modifying routes with a "sh oer border route static".

The injected route (being more specific than the default route) will be used and the flow will change of outgoing path.

Hope that this will help

New Member

Re: OER

Hi,

Please see the answers inline:

1. In the configuration of MC, when we define the external and internal interfaces, are these the interfaces of border router? Yes

2. If I only configure 'throughput' under 'learn', will the router be able to select one of the two Internet paths available to it based on optimal throughput? It is recommended to only configure "throughput" under learn. The border routers will then learn of the top throughput talkers. This only applies to the learning of prefixes and applications. Then PfR has to monitor these prefixes and applications. You will configure PfR in such a way to define what is important to monitor (jitter, loss, delay, MOS, etc) based on either prefixes or applications.

3. Shall I keep the floating static default routes on this edge routers towards Internet links? and will it select one of the two while forwarding Internet traffic?

Thanks in advance for your help. Yes, this is an option. PfR requires parent routes on two or more external interface to allow for routing of traffic by either creating smaller routes (longer prefix match) or policy based routes.

Best Regards,

Steve Lyons - Cisco

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