[ih] TCP RTT Estimator

[Barbara Denny]

 I don't recall ever hearing, or reading, about TCP transport requirements from the underlying network but I wasn't there in the early days of TCP (70s). 
I have trouble thinking the problem with the congestion assumption  wasn't brought up early but I certainly don't know.
barbara
    On Tuesday, March 11, 2025 at 02:10:26 PM PDT, John Day <jeanjour at comcast.net> wrote:  
 
 I would disagree. The Transport Layer assumes a minimal service from the layers below (actually all layers do). If the underlying layer doesn’t meet that normally, then measures are needed to bring the service up to the expected level.  Given that the diameter of the net now is about 20 or so and probably back then 5 or 6. Packet radio constituted a small fraction of the lower layers that the packet had to cross. Assuming packet radio didn’t have to do anything had the tail wagging the dog.

Of course the example some would point to was TCP congestion control assuming lost packets were due to congestion. That was a dumb assumption and didn’t take a systems view of the problem. (Of course, it wasn’t the only dumb thing in that design, it also maximized retransmissions.)

Take care,
John Day

> On Mar 11, 2025, at 17:02, Barbara Denny via Internet-history <internet-history at elists.isoc.org> wrote:
> 
> I do view packet radio as a stress test for the protocol(s).  I think it is important to consider all the different dynamics that might come into play with the networks. 
> I still need to really read Jack's message but there were also military testbeds that had packet radio networks.  I don't know what these users were trying to do. I was only involved if they experienced problems involving the network. My role was  to figure out why and then get it fixed (with whatever contractor that was working that part of the system, including BBN).
> barbara 
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>    On Tuesday, March 11, 2025 at 01:49:25 PM PDT, Dave Crocker <dhc at dcrocker.net> wrote:  
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> I have always been curious how packet radio may,  or may not, have impacted the calculations.  
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> At the IETF, the presentation about an actual implementation of IP over Avian Carrier noted that it provided an excellent test of this algorithm.
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> d/
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> Dave Crocker
> 
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