Internet diameter?

Christopher Morrow morrowc.lists at
Fri Nov 23 19:01:00 UTC 2018

On Thu, Nov 22, 2018 at 12:30 AM William Herrin <bill at> wrote:

> On Wed, Nov 21, 2018 at 7:58 PM Christopher Morrow
> <morrowc.lists at> wrote:
> > now, why does it matter?
> Good question! It matters because a little over two decades ago we had
> some angst as equipment configured to emit a TTL of 32 stopped being
> able to reach everybody. Today we have a lot of equipment configured
> to emit a TTL of 64. It's the default in Linux, for example. Are we
> getting close to the limit where that will cause problems? How close?
ah-ha! :) good, much easier to see the point with the goal in mind :)
So... you COULD spin up some set of traceroute measurements from
ripe-atlas, right? pick 5 probes per city and traceroute to common targets?

I think there are a few things to consider:
  1) not ever network exposes their hops all the time (mpls where the paths
no-decrement-ttl, for instance).
  2) the common user traffic pattern is likely not to fall into the 'too
many hops' problem because of cdn and/or other trickery to shorten the path
between end-user && content (to increase effective bw to the customer AND
lower latency,etc)
  3) I would think it rare for consumers (the largest pool of internet
users by role) to need to send packets to the far side of the internet
      Or put another way: "How would you pick what's important to measure
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