Why Peering Ratios?


Argument #1 - “I don’t want to haul your content all over the world for free.”

There are two hidden assumptions within this claim: First, that there is no revenue realized as a result of hauling this content traffic, and second, that there is an increased load on the backbone by “hauling” this traffic over a peering (“for free”) relationship. Let’s consider these broader arguments with a diagram.

Figure 1 – Content Heavy ISP A Peers with Big ISP.

In this example (see figure 1 above), the Content Heavy ISP A peers with a Big ISP which has a large global network spanning the United States and Europe. In this example, the Content Heavy ISP A is peered with the Big ISP Network in a single location and has a 30:1 outbound to inbound traffic ratio. As is typical with today’s web (http) traffic, we see small requests from the Big ISP access heavy customers generate large responses from the Content Heavy ISP A.

Next (see figure 2 below) let’s consider an Access Heavy ISP A in the exact same situation: Access Heavy ISP A peers with Big ISP, and Access Heavy ISP A Customers send small requests across to Big ISP’s Content customers, which in turn send big responses back.

Figure 2 – After Access Heavy ISP A Peers with Big ISP

Notice that the Big ISP Backbone load is identical in these two scenarios.

Counter Argument #1 – Since the load on the backbone is the same in both scenarios, there is no technical rationale for discriminating against one versus the other – the load on the Big ISP is identical!

Counter-Argument #2: The Big ISP in these scenarios is hauling the traffic across the globe on behalf of its customers. Massive outbound asymmetry or massive inbound asymmetry is an artifact of the type of customer served, regardless of whether served via peering or transit relationships.

What is different between these two scenarios is who is paying and in which direction the traffic is loading the backbone. In the first scenario, the Big ISP Content Heavy customers are paying Big ISP to distribute its content to the entire Internet (including to Access Heavy ISP A customers). In the second scenario, the Big ISP Access Heavy customers are paying the Big ISP for Transit (access to the global Internet including the Content Heavy ISP A content). In both situations, Big ISP is being paid for the traffic exchange – it is not “hauling the traffic all over the world for free.”

Argument #2The_Folly_of_Peering_Ratios_2.html