[Bloat] Educate colleges on tcp vs udp

[Jonathan Morton]

> On 27 May, 2021, at 10:42 am, Hal Murray <halmurray+bufferbloat at sonic.net> wrote:
> 
> I would back up.  You need to understand how networks work before discussing 
> TCP or UDP.
> 
> The internet is not like a phone system.  There are no connections within the 
> network and hence no reserved bandwidth and nothing like a busy signal to tell 
> you that the network is full.  (There are host-host connections, but the 
> network doesn't know anything about them.)  Packets are delivered on a 
> best-efforts basis.  They may be dropped, delayed, mangled, or duplicated.

You're right - the distinction between Bell and ARPA networking is a crucial foundation topic.

A discussion of the basic 10base Ethernet PHY (and how that fundamentally differs from the 8kHz multiplex of a traditional telephone network) might be helpful, since the intended audience already understands things like modulation.  Once that is established, you can talk about how reliable stream transports are implemented on top of an ARPA-style network, using Ethernet as a concrete example.

There are a lot of gritty details about how IP and TCP work that can be glossed over for a fundamental understanding, and maybe filled in later.  Things like Diffserv, the URG pointer, option fields, and socket timeouts are not relevant topics.  There's no need to actually hide them from a header diagram, but just highlight the fields that are fundamental to getting a payload from A to B.

 - Jonathan Morton