[e2e] What should e2e protocols know about lower layers?

[Erik Nordmark]

> > If IPv4 has such a notion from a congestion control
> > perspective then something is broken.
> 
> 
> See RFC1112.

RFC 1112 on Hosts Extensions for IP multicasting doesn't talk about
congestion control.

Did you intend to type 1122?
It does talk about both "local" and "congestion control" but the former
is the subject of section 3 on IP and the latter is in section 4 on transports.
 So I don't see where a notion of local is applied to congestion control.
Do you have a reference to a specific section?

> > RFC 2002 (Mobile IP) uses IPinIP tunneling to make what you thought was 
> > local (in the same subnet prefix) be capable of being anywhere in the Internet.
> 
> 
> Who said it had to be in the same subnet? IPinIP tunnels are 
> point-to-point links, which means if they use subnets they are by 
> definition misconfigured.

I think this is an argument about a half-full vs. half-empty glass...

The use of local/remote in RFC 1122 section 3.3.1.1 is for the purpose
of determine whether or not the packet should be sent to a router.
Thus a possible interpretation of this is that "local" means exactly that -
packets are not sent to a router.
Another possible interpretation is that "local" means "close by" or
"on the same high-performing instrastructure as the sender's network
interface".
Both are possible interpretations.
Rubustness would lead me to pick a particular one of them in the context of
congestion control.

  Erik