Re: [Int-area] Side meeting follow-up: What exact features do we want from the Internet? minmax

[Alexandre Petrescu <[e-mail]>]

Le 08/12/2021 à 15:15, Alexandre Petrescu a écrit :
> The advantage of talking 'minimum cell size' (MCS?) instead of
> 'maximum transmission unit' (MTU) is in that it fits better to a
> preceding 'minimum' qualifier.
> 
> A 'minimum MTU' term expands to a 'minimum maximum transmission
> unit'. That construct can be ambiguous to an implementer.  Is it a
> 'minimum transmission unit'?  Or is it the smallest of all MTUs of
> all link designs?
> 
> On another hand, a 'minimum minimum cell size' is clearly just a
> minimum cell size, just further accentuated in its minimization: a
> 'minimum minimorum' if one wishes.  Where MCS is 576 a minimum MCS in
> IPv6 could be 41: 40 bytes of header and 1 byte of payload.  Or maybe
> 40 if there is no payload.  Or maybe 321 bits if there is just one
> bit of payload (an on/off switch or flag in IoT speak).

And, in the desiderata for exact features we want from the Internet, I
would add the following:

- one should not worry about an IPv6 minimum MCS be of size 321bit for
transmitting just 1bit of valuable information.  Because the structure
and working of the entire Internet is reflected in these 321bits: the
billions of nodes and billions of billions of working paths between all
of them is represented in just these 321bits.  Thanks to these 321bits
the 1bit IoT payload value can be sent or received between any of these
across any distance at any speed.

So, the feature requested is to not try to reduce the power of these
321bits by designing compression schemes in the Internet at large.

Compress one single bit of these 321bits and the Internet is reduced.

Alex

> 
> Alex
> 
> Le 08/12/2021 à 02:38, Templin (US), Fred L a écrit :
>> This conversation is missing some fundamental points – really the
>> most important
>> 
>> points – which are the minimum sizes guaranteed to work everywhere.
>>  For IPv6,
>> 
>> the minimum MTU/MRU are 1280/1500. For IPv4, they are only 68/576
>> but since
>> 
>> the IPv4 network supports fragmentation we can nominally designate
>> the IPv4
>> 
>> minimum MTU as 576 also if we clear the DF bit. It means that,
>> without probing
>> 
>> or having some divine knowledge of paths that have not been
>> previously visited,
>> 
>> the ONLY sizes guaranteed to work are 1280 for IPv6 and 576 for
>> IPv4.
>> 
>> Now take the case of Multinet where a path may traverse multiple 
>> concatenated
>> 
>> IP networks of arbitrary IP protocol versions - remember “Catenet”?
>>  Since there
>> 
>> may be no advanced knowledge of network IP protocol versions, the
>> most we can
>> 
>> absolutely and for sure count on across the entire path is 576.
>> 
>> What this gives us is not the **maximum packet size**; instead, it
>>  determines the
>> 
>> **minimum cell size**. We know that a 576 cell will traverse all 
>> paths, so we never
>> 
>> send a non-final cell smaller than this (which might trigger a tiny
>>  fragment alarm).
>> 
>> But, we can certainly send packets larger than the path MTU -
>> **much** larger in
>> 
>> many cases. And for paths that support them, we can also send
>> Brian’s jumbograms.
>> 
>> Speaking of jumbos, on a different list I made a point about how
>> this all harkens back
>> 
>> to RFC1149 and RFC6214. But nowadays, we can imagine substituting a
>>  memory stick
>> 
>> for the slips of paper with whitestuff and blackstuff and those
>> avian carriers will
>> 
>> transport jumbos just fine. Not quite unlimited MTU, but close
>> enough.
>> 
>> Fred
>> 
>> 
>> _______________________________________________ Int-area mailing 
>> list [e-mail] 
>> https://www.ietf.org/mailman/listinfo/int-area
> 
> _______________________________________________ Int-area mailing
> list [e-mail] 
> https://www.ietf.org/mailman/listinfo/int-area