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Performance Routing and iBGP

I'm just starting to get my feet wet with Performance Routing and I was wondering how I should classify my iBGP link. Is it internal or external? Does is really matter? My topology consists of two Cisco ISR G2 3945s running 15.2(4)M6a acting as border routers. Each router has one eBGP connection to a single ISP. The routers are directly connected to each other as well and I'm running iBGP across that link so each router has routing information from both of the ISPs. If the directly attached ISP doesn't have the best path to a given prefix, the traffic gets sent across the iBGP link to egress the other ISP. The MC is on another router. The iBGP link is 1Gbps and our two eBGP links are about 100Mbps. 

I'm thinking it should be classified as internal. I obviously don't need to worry about capacity on the link since its fed by 2 x 100Mbps connections and I don't need to set any specific PfR policies on it. Can anyone share their experiences on how they configured PfR in this situation

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The external interfaces are those you want PfR to analyze performance for.  So, from what you describe, your iBGP would be defined as internal.

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