[TUHS] OSI stack (Was: Posters)

Grant Taylor gtaylor at tnetconsulting.net
Fri Feb 8 04:07:27 AEST 2019

Seeing as how this is diverging from TUHS, I'd encourage replies to the 
COFF copy that I'm CCing.

On 02/06/2019 01:47 PM, Kevin Bowling wrote:
> There were protocols that fit better in the era like DeltaT with a 
> simpler state machine and connection handling.  Then there was a mad 
> dash of protocol development in the mid to late ‘80s that were measured 
> by various metrics to outperform TCP in practical and theoretical 
> space.  Some of these seemed quite nice like XTP and are still in use in 
> niche defense applications.


> Positive, rather than negative acknowledgement has aged well as 
> computers got more powerful (the sender can pretty well predict loss 
> when it hasn't gotten an ACK back and opportunistically retransmit).  
> But RF people do weird things that violate end to end principle on cable 
> modems and radios to try and minimize transmissions.

Would you care to elaborate?

> One thing I think that is missing in my contemporary modern software 
> developers is a willingness to dig down and solve problems at the right 
> level.  People do clownish things like write overlay filesystems in 
> garbage collected languages.  Google's QUIC is a fine example of 
> foolishness.  I am mortified that is genuinely being considered for the 
> HTTP 3 standard.  But I guess we've entered the era where enough people 
> have retired that the lower layers are approached with mysticism and 
> deemed unable and unsuitable to change.  So the layering will continue 
> until eventually things topple over like the garbage pile in the movie 
> Idiocracy.

I thought one of the reasons that QUIC was UDP based instead of it's own 
transport protocol was because history has shown that the possibility 
and openness of networking is not sufficient to encourage the adoption 
of newer technologies.  Specifically the long tail of history / legacy 
has hindered the introduction of a new transport protocol.  I thought I 
remembered hearing that Google wanted to do a new transport protocol, 
but they thought that too many things would block it thus slowing down 
it's deployment.  Conversely putting QUIC on top of UDP was a minor 
compromise that allowed the benefits to be adopted sooner.

Perhaps I'm misremembering.  I did a quick 45 second search and couldn't 
find any supporting evidence.

The only thing that comes to mind is IPsec's ESP(50) and AH(51) which—as 
I understand it—are filtered too frequently because they aren't ICMP(1), 
TCP(6), or UDP(17).  Too many firewalls interfere to the point that they 
are unreliable.

> Since the discussion meandered to the distinction of path 
> selection/routing.. for provider level networks, label switching to this 
> day makes a lot more sense IMO.. figure out a path virtual circuit that 
> can cut through each hop with a small flow table instead of trying to 
> coagulate, propagate routes from a massive address space that has to fit 
> in an expensive CAM and buffer and forward packets at each hop.

I think label switching has it's advantages.  I think it also has some 

I feel like ATM, Frame Relay, and MPLS are all forms of label switching. 
  Conceptually they all operate based on a per-programed path.

Grant. . . .
unix || die

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