[e2e] Protocols breaking the end-to-end argument

[William Allen Simpson]

Jaime Mateos wrote:
> I'm working on a project about the current challenges the Internet is 
> presenting to the end-to-end argument. I'd be interested to know about 
> any protocols, currently in use, that break the end-to-end principle and 
> the context where they are used.

You could add the Broadcom chip sets to your list.  Not a protocol per se,
but they inexplicably "handle" TCP segmentation.  Usually used in a host
(bad enough in my opinion), but could create utter havoc in a router.

So far, I've noticed:

   NetXtreme II 1 Gigabit
   Tigon 3

When I recently proposed actually checking for correct TCP option sizes,
the Linux driver's author says:

     You're being way too anal here, and adding these checks to
     drivers would be just a lot of rediculious bloat. [sic]