nanog mailing list archives

Re: Internet diameter?


From: Christopher Morrow <morrowc.lists () gmail com>
Date: Fri, 23 Nov 2018 14:01:00 -0500

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

On Wed, Nov 21, 2018 at 7:58 PM Christopher Morrow
<morrowc.lists () gmail com> 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
to?"

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