CDNs for carriers

Jared Mauch jared at puck.nether.net
Mon Jun 29 14:21:05 UTC 2015


> On Jun 29, 2015, at 9:59 AM, Mike Hammett <nanog at ics-il.net> wrote:
> 
> Simple flows wouldn't necessarily tell you if you're pulling a bunch from a Netflix caching box on your upstream somewhere. You'd think you had a huge amount going to your current upstream because technically you do, but a local cache or peer could alter that significantly. As we've been starting up our IX, we're finding that we can send lists of ASNs and prefixes and the various CDNs will tell us how much traffic they see going to our customers. Combine that with what flows tell you and I think you've got a good approach. 
> 
> What are some good approaches to determining traffic levels to not only ASNs, but also that ASN's downstream ASNs? You may have ASNs A, B, C, D and E in your flows. Say none of them represent more than 5% of your traffic by themselves. If B, C, D and E all purchase transit from A and you can reasonably peer with A, you actually can move 25% of your traffic over to a peer. Maybe there is no good approach at doing that without a bunch of manual work or paying someone else to do it. 
> 
> Looking at some stats from one of our customers that is also going through Equinix Chicago, for their average inbound ~37% of traffic was Netflix, Google was 34% and the next highest was Apple at 5%. Note that Akamai had left Chicago Equinix by this point, so they wouldn't be reflected in those numbers. Those percentages are percent of all traffic they send to Equinix. I believe about 2/3s of their total transit went to Equinix when that got turned up. Their total traffic went up once joining the Equinix IX, presumably because they were now bypassing some congestion somewhere. 
> 

Sure.  There are a lot of dynamics to consider.  It’s fairly easy to look at TCP speeds and retransmissions to determine the link speed involved.  I’ve seen many CDNs quickly identify congested or paths without congestion and engage in some adaptive behaviors.

This being said, there is not a single solution to everything.  Chris mentioned using DNS, which is a nice method assuming you see all the queries within your traffic cone.

- Jared


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