RINA - scott whaps at the nanog hornets nest :-)

Sun Nov 7 08:58:13 UTC 2010

> 
> I used to run a large academic network; there was a vanishingly small
> incidence of edge ports supporting >1500byte MTU. It's possibly even
> more tricky than the IX situation to support in an environment where
> you commonly have mixed devices at different speeds (most 100mbit
> devices will not support >1500) on a single L2, often under different
> administrative control.

At the edge, sure.  There are all sorts of problems there.  The major
two being 1: much of America still uses dialup or some form of PPoE that
has <1500 MTU anyway.  The problem at the other end is that the large
content providers are generally behind load balancers that often don't
support jumbo frames.  So if you are talking to an ISP that serves
residential customers or "eyeballs" that are viewing content from the
major portals, it makes no sense.  But if you are talking about data
between corporate data centers or from one company for another where
they are ethernet end to end, the picture changes.  Dykstra's note of
that study in 1998 showed that while the majority of the *packets* were
<1500 the majority of the *data bytes* were in packets >1500.

So considerably more than 50% of the packets were moving <50% of the
data.

But the networks that are now running >1500 internally can't talk to
each other with those packet sizes across the general Internet until the
longer haul path supports it and again you are talking about a small
number of end points sending large amounts of data.  It will work itself
out but it will probably be consumer demand for higher performance data
streams that finally does it.  (only awake to make sure nothing goes
bonkers during the time change).