[e2e] Explicit Transport Error Notification

[Christian Huitema]

> This work represents a very good start to investigations into ETEN.  I 
> would appreciate any feedback related to the work.  In particular, 
> thoughts on whether or not the potential performance improvements would 
> justify deployment.  If deployment is justified, which areas of research 
> may be best to address?   

Explicit error notification is just one way to distinguish between losses due to transmission errors and losses due to congestion. An alternative way is to use explicit congestion notification, and assume that packet losses are due to other factors -- e.g., only shrink the window on ECN, and expend it on the ACK. There are obvious deployment issues, but these could be solved if NASA is operating in any kind of controlled set-up. In any case, the ECN only option could be simulated in NS...

-- Christian Huitema