[e2e] What's wrong with this picture?
Jon.Crowcroft at cl.cam.ac.uk
Sun Sep 13 02:43:39 PDT 2009
this made me think- the problem with the
ill-defined "best effort" is that
IP as a service falls victim to the
dictatorship of the majority - the internet is a
network of networks as you rightly remind us, and
those networks constantly expand to include new things -
some of the new things are great
(greater speed, lower latency)
but some are bad
(lower speed, higher latency, interference induced packet loss)
and some are even worse
(re-definitions of service to include
throttling of some flows by port, allegedly for TE or policy,
firewall filtering of default legacy setings
making positive re-definitions of field use (e.g. ECN)
hard to deploy...)
so what is seen by IP (and therefore has to be coped with by
TCP and most applications) has to expand to include the worst
as well as the better (democracy in action)....
its probably too late to do this,
but a formal definition of best effort semantics
(including the postel principle)
would be really good in stopping mission creep...
on a more specific note,
I implemented an IP forwarding box
at least twice and one time,
actually decremented TTL on a 1 second timer
as well as once per hop,
(but that was back when an output link was
slow enough that a queue could persist that long)
but fixing time based discard isn't, for me
the crucial thing -
fixing buffer sizes in routers (as per damon wischik
and others' work) seems more like
repairing the root cause...
In missive <aa7d2c6d0909121354l77eff82bn36225025833b50d5 at mail.gmail.co
m>, Lachlan Andrew typed:
>>I'm glad my provocative comments stimulated a response.
>>I'm happy to agree that they're not a sound way to make incremental
>>changes to the current network, but they reflect a particular hobby
>>horse of mine, that the "inter" has been forgotten in the internet.
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