On 5/11/12 09:45 AM, Jeffrey Walton wrote:
On Sat, Nov 3, 2012 at 9:08 PM, <[email protected]> wrote:
> ...
> In practice, the 7 layer model was not an implementation recipe - TCP/IP
> in the broader Internet sense showed that engineering required working
> with the tech of the time, not the abstractions from some CS class or
> government contract sales team. TCP in the narrow sense shows it again
> - sticking TCP in layer 4 and stopping there doesn't work - it claims
> everything is a stream, when 'everything is a datagram' is closer to the
> truth, and a more useful assumption. TCP further assumes it can
> reliably deliver data, when actually it's only reliable enough if you
> care only enough to do the demo.
> ...
I don't know what to think of the following, but it may be germane:
http://rina.tssg.org/docs/JohnDay-LostLayer120306.pdf
Somewhat off topic, but Day has another good presentation at
http://csr.bu.edu/rina/KoreaHowtoCleanASlate100219.pdf.
* Mobility is cumbersome and doesn’t scale
- Excuse: What do you mean? It works. . . . . Sort of.
- Actual: With only physical addresses, hard to do “re-locatable” addressing
I think they (both) germane and on topic - but he's looking at it from a
completely different perspective. We are talking about how to make the
net work across phones, John Day is talking about what is wrong with net
from fundamentals. IOW, we're assuming IP as the given, he's attacking
IP & TCP as a broken result of a muffed layer architecture, and moving
to replace it with how it should be.
Where we meet is that some of his conceptual (?) criticisms are exactly
why the net does not work well across mobile.
E.g., slide 40, talking about connection v. connectionless:
======================================
Resolving the CO/CL Problem
• Lets look at this very carefully
• What makes connection-oriented so brittle to failure?
• When a failure occurs, no one knows what to do.
• Have to go back to the edge to find out how to recover.
• What makes connectionless so resilient to failure?
• Everyone knows how to route everything!
• Just a minute! That means!
• Yes, connectionless isn’t minimal state, but maximal state.
• The dumb network ain’t so dumb.
• Where did we go wrong?
• We were focusing on the data transfer and ignoring the rest:
11/01/06 slide 40
© John Day, 2010 All Rights Reserved
======================================
iang
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