Google's peering, GGC, and congestion management

[Baptiste Jonglez <baptiste () bitsofnetworks org>]

Hi,

In its peering documentation [https://peering.google.com/about/traffic_management.html],
Google claims that it can drive peering links at 100% utilisation:

> Congestion management
>
> Peering ports with Google can be run at 100% capacity in the short term,
> with low (<1-2%) packet loss. Please note that an ICMP ping may display
> packet loss due to ICMP rate limiting on our platforms. Please contact
> us to arrange a peering upgrade.

How do they achieve this?

More generally, is there any published work on how Google serves content
from its CDN, the Google Global Cache?  I'm especially interested in two
aspects:

- for a given eyeball network, on which basis are the CDN nodes selected?

- is Google able to spread traffic over distinct peering links for the
  same eyeball network, in case some of the peering links become
  congested?  If so, how do they measure congestion?

Thanks for your input,
Baptiste

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