[e2e] Are we doing sliding window in the Internet?

sisalem@fokus.fraunhofer.de sisalem at fokus.fraunhofer.de
Mon Jan 8 06:41:39 PST 2007

>> not that hard to achieve.  The best-effort delivery with no fairness
>> enforcement by the network itself is asking for trouble, and I'm suprised 
>> that it still persists.
> You probably want to read the congavoid paper or RFC 2581.

> You will learn from that, that fairness enforcement _does_ exist.
just a short remark: I would assume that the definition of fairness
here is that two TCP connections with the same RTT and packet size
would receive the same bandwidth share.
Hence, fairness enforcement is only partially done. Two
TCP sessions with different congestion avoidance schemes (e.g., one
with SACK and another one with Reno) will not achieve the same
bandwidth share under the same RTT conditions (whether this is to be
considered unfair though is another issue which has more to do with
philosophy). And a UDP flow is not interested in fairness at all as

regarding the input about enforcing fairness in the network. I think
that the painful experience ATM and ABR taught us already, that
network based fairness enforcement schemes are theoretically great but
practically too complex to be of practical use

>> If the network is enforcing fairness, there is nothing a misbehaving host
>> (or millions of misbehaving hosts) could do to degrade performance as seen
>> by other users (except as a part of coordinated DDoS attack on a 
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

> I appreciate that you name even one problem yourself.
>> specific target).
>> How hard it is to turn the Fair Queueing knob to "on" on the gateways?
>> So, why exactly should we care?
> I don´t know, why "we" should care. But I frankly tell you, what you 
> should care fore.
> First of all, you most probably want to care for a good text book on 
> networking because what you write on this topic simply makes my hair 
> stands on end.
> The second is a personal advice I tried to give you already yesterday.
> Perhaps you should reconsider your opinons from time to time based upon
> your personal life experience. Times are changing and so are opinions.
> It is always a good idea to put some kind of low pass filter on opinions
> and to avoid both, extreme positions and simple answers to complex 
> questions.

> Finally, and I really think so, we should politics out of this list.

> When we had birthday parties in our familiy or similar occasions, I was
> always given a strong advice by my father concerning topics of discussion:
> " NO sports, NO politics, NO religion."
> You can talk about anything but these.

> Believe me: My father was perfectly right.

> And for this list: You´re welcome to contribute to the discussion of end
> to end issues.

> I apologize for posting on this issue again. Please, Lynne, Vadim, let
> us return to the subject of this list again. Not only for the benefit of
> ourselves but for the benefits of all the other readers. Particularly 
> the thread on sliding window is an interesting one and I learned a lot
> from it. Perhaps, others find it interesting as well, at least there are
> far too many contributions for a boring thread. It would be a pity if 
> people would leave thr thread or even the list because of continous off
> topic posts on politics and similar issues.

> Thanks.

> Detlef

Best regards,
 Dorgham                            mailto:sisalem at iptel.org

More information about the end2end-interest mailing list