[ih] principles of the internet

[Dave Crocker]

On 6/3/2010 7:44 AM, Matthias Bärwolff wrote:
> To return to my initial go with the list of principles, let me put
> forward a revised version applicable to the classic definition of the
> Internet ("roughly transitive closure of IP-speaking systems"):

Since you are providing a precise and, yes, popular view of the definition of 
the Internet, I'll offer an elaboration rather than correct.  (I'm assuming that 
"transitive closure" is meant to imply any IP speaker with direct or routed 
access to the public, default-free multi-provider backbone.)

The elaboration is based on the difference between focusing on layer 3 versus 
focusing on layer 7.  For details:

    To Be "On" the Internet

    <http://www.ietf.org/rfc/rfc1775.txt>

For some unknown reason, my own preference is to focus on perspective of the 
application layer, and not be distracted by possible limitations or variations 
at layer 3, unless they get in the way of application use.

But that's just me...  (and most users.)


> So far, we still have plenty of scope for functions in the network.
> However, once we take minimal coupling, least privilege, cascadability,
> and best effort into account, there is actually a fairly low upper bound
> on what functions the intermediary network nodes may assume without
> collapsing the potential scale of the Internet to trivial proportions.

The real challenge is justifying this assessment well enough to guide future 
designers.  There is a persistent tendency to believe that changes are easy to 
make within the infrastructure.



>> The complexity of the Arpanet design and layering might permit a bit of
>> debate about whether it qualified as being based on best effort.
>> Alohanet's simplicity does not (permit debate.)
>
> Why not? Alohanet (pure Aloha) capacity was at 1/(2e), and downlink data
> was not even acknowledged (for performance reasons). Ethernet capacity
> has been at some 98 percent right away, and packets hardly ever got lost
> (safe in screwed up installations). Best effort certainly doesn's mean
> no effort (as in Alohanet), but has probably always meant "reasonable",
> "sane" effort. (But that's just my two cents, Richard was gonna
> enlighten us us to the three meanings of best effort.)


Alohanet was not no effort.  It had retransmission.

But it merely kept things extremely simple.  That its version of 'best' was 
relatively poor and that the Ethernet's version was a lot better does not make 
either less an example of 'best'.

d/
-- 

   Dave Crocker
   Brandenburg InternetWorking
   bbiw.net