[ih] How Plato Influenced the Internet

[Brian E Carpenter]

On 27-Aug-21 10:18, Jack Haverty via Internet-history wrote:
> I do remember that there were experiments over the years, and at least a 
> few RFCs defining meanings for the values of that TOS field we put in 
> the IP header.   "Stable latency" could have been a useful type of 
> service, making a virtual circuit look more like an old-school actual 
> circuit.   I'm not sure if it's in any of those RFCs, or the similar 
> mechanisms which I gather have been defined in IPV6.

Given that the Internet is a great big statistical multiplexer, the 
ambitions of the differentiated services ("diffserv") work that
repurposed the "TOS" bits were limited to *bounded* latency aimed at
services such as Voice over IP. This has been very widely deployed
in corporate networks, for example. Getting differentiated services
to work across the open Internet is a much harder problem; it can only
happen if there are adequate service level agreements at all ISP
interconnections along the path. Many many RFCs have addressed this
topic, and it's still being worked on in the IETF. Just one sample:
https://www.rfc-editor.org/rfc/rfc8100.html

A feature of diffserv is that it's defined identically for IPv4
and IPv6.

(I was co-chair of the original diffserv WG that produced
https://www.rfc-editor.org/rfc/rfc2474.html in 1998.)

There's a current IETF effort on 'deterministic networking'.
I have my doubts, but you can read all about it at
https://datatracker.ietf.org/wg/detnet/documents/

Regards
   Brian Carpenter

> 
> Some of those RFCs (and TOS specifications) might even have made it to 
> becoming a "standard".   But IMHO the history of the Internet 
should 
> focus on what happened "in the field" of the Internet we all use 
> today.   It's hard for me as a user to tell, but I personally 
haven't 
> seen any evidence that any OS, or application, uses those TOS settings, 

> or that any ISP and/or router manufacturer has equipment that behaves 
> differently depending on the TOS settings. There have been "test the 
> net" services around for a while, primarily measuring throughput, but 
> recently I've seen a few that at least report on latency.   Still 
> haven't seen any ISP or equipment vendor touting their products' 
> abilities to offer different types of service.   Perhaps that's even 
> illegal now given "net neutrality"?
> 
> So it seems that the TOS functionality of IPV4 may have been evolved a 
> bit with some experimentation that occurred, but it doesn't seem to have 
> gotten into the live Internet.
> 
> That's one thing that led me to the observation that the History of the 

> Internet should include what didn't happen, and why.
> 
> /Jack Haverty
> 
> 
> On 8/25/21 12:54 PM, Dave Crocker wrote:
>> On 8/25/2021 12:13 PM, Jack Haverty via Internet-history wrote:
>>> Low latency was also important for things like conversational voice,
>>
>> Given the new ability to be interactive with a range of 'users', there 

>> was experimentation about usability issues.  Lower latency has obvious 
>> benefit.  But one experiment demonstrated it was not an absolute.
>>
>> Given an experience with significantly /variable/ latency, where the 
>> average was lower latency, versus an experience with very stable 
>> latency, but at a higher average, users preferred the latter.
>>
>> d/
>>
> 
>