[e2e] overlay over TCP

[Randall Stewart]

Comments below :-D

Coene Lode wrote:
>>David P. Reed wrote:
>>
>>>The reason not to depend on SCTP is the same reason that UDP isn't 
>>>adequate. 
>>
>>I said DCCP, not SCTP, FWIW, and for a number of reasons.
>>
> 
> 
> And what might be those reasons????
> DCCP will have just about the same deployment difficulties that any other
> new transport protocol has to jump through....


Even worse for DCCP .. since its further behind SCTP.. and time
makes a difference.. let me tell you :-D
> 
> 
>>>The social (non-technical) processes of the "internet 
>>>community" have labeled anything non-TCP as POISON, KEEP OUT.
>>>We have middleboxes and routers that chuck stuff like that on the floor.
> 
> 
> Well even the wrong portnumber with TCP could put you up the creek without a
> paddle....
> Seems the drop-to-floor boxes have already won then... 
> So all overlay networks would be welded to TCP for the rest of their
> lives.... 

There is hope.. eventually SCTP will be in all the firewalls and NAT's
and then sometime down the road from that you will find DCCP in
the boxes too... but in either case it will be some time yet for
SCTP and DCCP has not even gotten that far yet...
> 
> 
>>Sure - at that point, you're stuck going over TCP, but then you're also 
>>stuck with a few other things:
>>
>>	- ACK aggregation delays
>>	- messages split across packets (lack of fate sharing,
>>	  so higher loss rates at the message level)
>>	- NATing that will kill interior apps anyway
>>		any app the NAT doesn't _already_ know about
>>
>>
>>>Interop is about allowing everything not explicitly prohibited, but 
>>>don't tell that to the "corporate IT" folks, who want to give you 
>>>freedom from pesky things like ways to do your job better...  some jerk 
>>>with a beard and a technical education knows how and when you should 
>>>communicate, and he will let you know what communications technology you 
>>>will be allowed to use.   Cisco's firewall division tells him what's OK, 
>>>and God (or TPC from the President's Analyst) tells Cisco.
>>
>>In that case, you're safer doing IP over HTTP (yes, there is such an 
>>animal).
> 
> 
> And before you know it, all network and transport protocol have a XML
> syntax... :-)

ug... that would be fun would it not :-D
> 
> Seriously: you can extend TCP or deploy an already existing transport
> protocol that gets close to what you want.
> If it has to do something similar to UDP then PR-SCTP and/or DCCP might do
> the job....
> (PR-SCTP: Partial relialability extension for SCTP)
> If it should do something similar to TCP, then at present SCTP might be
> interesting....
> Extending TCP or using SCTP/DCCP functionality is actually the battle
> between: 
> (1)Put functionality in the transport layer 
> Versus
> (2)The application should do this functionality because it knows what it is
> doing...
> 
> (2) Makes sense for some applications, however most applications wouldn't
> mind (1) because, if later they find out that the functionality actually
> helps them(you never know..), then they don't have to reimplement it in
> their own code, they just have to throw a few switches....

I agree..

Most apps would rather not get involved and rather just have
a service it can use... yes there will always be some that
one more control and involvment.. but just look how little control
TCP gives you and you see that large numbers of apps still use it :-D

R
>  
> 
>>Joe
>>
> 
> 
> Yours sincerely,
> Lode Coene
> 
> Siemens COM
> atealaan 34          2200 Herentals, Belgium
> E-mail: lode.coene at siemens.com
> Tel: +32-14-252081
> Fax: +32-14-253212
> 
> 
> 


-- 
Randall Stewart
803-345-0369 <or> 815-342-5222(cell)