Re: [tcpm] WG status update

[Bruno Mongazon-Cazavet <[e-mail]>]

  Le 15/11/2010 13:54, Lars Eggert a écrit :
> Hi,
>
> On 2010-11-15, at 12:27, Bruno Mongazon-Cazavet wrote:
>> Please let me know, if from the design point of view, the WG would consider the opportunity to have a lightweight MPTCP that would look like TCP-Rehash.
> given that the IETF is already working on MPTCP, it's a bit difficult to see why we should work on another extension to TCP that does some of what MPTCP does, but not all of it, and in a way that is not interoperable with it.
>
> It's not like MPTCP will significantly increase the footprint of the network stack.

Sorry but yes it does.

The numbers are currently the following:

MP-TCP patch on 2.6.28 => 16270 Line Of Code
TCP-Rehash on 2.6.34 => 2357 Line Of Code

Percentages are currently the following (net/ipv4 sub-directory C files 
only, not counting the core nor header files):

MP-TCP on 2.6.28 => (16270 / 82925) * 100 ~= 20 %
TCP-Rehash on 2.6.34 => (2357 / 80977) * 100 ~= 3%

Giving the fact that the MP-TCP code i use does not provide yet "coupled 
congestion control" there are a few chance the trend can change.

So numbers do actually tell something logical: TCP-Rehash is designed 
with minimal functionality, MP-TCP provides more functionality.

I just wonder if MP-TCP can benefit from a behavior that would only cost 
a little (if ever, need to be checked) and provide a minimal behavior 
that can sometimes be sufficient.

I am free to discuss this and other's opinions are welcome.

Bruno.

> Lars