Re: [re-ECN] Two questions about CONEX

[Bob Briscoe <[e-mail]>]

Kevin,

At 23:56 09/05/2010, Kevin Mason wrote:
> >From a simple transport overhead view, at what point is adding any 
> extension header (assuming that is the IPv6 approach) less 
> efficient than putting the information is a separate packet.
>
>For some protocol a separate packet might be needed anyway if the 
>frequency of backward responses inherent in the protocol in use is 
>too low for the information to be usefully acted on. I suspect any 
>application using such a protocol will be highly inelastic and would 
>need some higher layer longer duration controls in place to avoid 
>congestion impacts anyway.

We deliberately designed re-ECN so that an e2e transport with 
infrequent feedback suffers the consequences of the extra risk it 
takes. This encourages it to
- either use sufficient feedback,
- or, in the absence of sufficient feedback, for its increases in 
sending rate to be more cautious.

Cheers


Bob


________________________________________________________________
Bob Briscoe,                                BT Innovate & Design