Re: MultiPath TCP in the Linux Kernel

[Christoph Paasch <christoph.paasch@uclouvain.be>]

Hi,

MultiPath TCP is not a port of SCTP. It is based on regular TCP and presents a 
regular socket-api to the application. Thus applications do not have to be 
modified.

MPTCP opens several TCP-subflows across it's different IP-addresses, and lets 
the data go over these different TCP sessions. To synchronize the data-
transfer MPTCP uses TCP-options. Thus, on the wire it looks like regular TCP, 
with the only difference being that there are additional TCP-options.

MPTCP increases the throughput, because it uses the TCP-subflows 
simultaneously. With our implementation we got 2Gbps throughput for a single 
iperf-session on a machine having two 1Gb-interfaces (using jumbo-frames), 
whereas regular TCP could only go up to 1Gbps, as it only uses one interface.

To maintain bottleneck-fairness the Coupled Congestion Control controls the 
congestion window of the individual subflows (included in the implementation 
since the latest release).
http://datatracker.ietf.org/doc/draft-ietf-mptcp-congestion/


Cheers,
Christoph

P.S.: We have a public webserver running MPTCP at http://mptcp.info.ucl.ac.be
So you can directly try out the power of MPTCP... ;-)

On Thursday, January 20, 2011 wrote Peter Chacko:
> SCTP already provides that , and is TCP Multi-Path is going to be a port of
> it or any other difference ?
> 
> We are looking to use SCTP for this feature, but as we found it it has not
> kicked off , because of its firewall issues, we are trying add
> Multi-Pathing at application layer, sharing all the congestion states(like
> CM idea) as we are building a WAN optimized storage replication module as
> part of our cloud storage gateway development.
> 
> Curious to see more info on this.
> 
> Thanks
> 
> 2011/1/20 Christoph Paasch <christoph.paasch@uclouvain.be>
> 
> > Hi all,
> > 
> > The IETF is developing a new transport layer solution, MultiPath TCP,
> > which allows to efficiently exploit several Internet paths between a
> > pair of hosts,
> > while presenting a single TCP connection to the application layer.
> > 
> > At the UCLouvain in Belgium we are developping the support for MultiPath
> > TCP
> > in the Linux Kernel. The implementation is a major extension to the Linux
> > TCP-
> > stack.
> > 
> > For general information, access:
> > http://inl.info.ucl.ac.be/mptcp
> > https://scm.info.ucl.ac.be/trac/mptcp/
> > 
> > To access the git-repository:
> > git://scm.info.ucl.ac.be/mtcp.git
> > 
> > branches:
> >        mptcp_2.6.36 - based on Linux Kernel 2.6.36
> >        mtcp_no_subrcvqueue - based on Linux Kernel 2.6.28
> > 
> > For questions, feedback,... feel free to subscribe to the mptcp-dev
> > Mailing-
> > List:
> > https://listes-2.sipr.ucl.ac.be/sympa/info/mptcp-dev
> > 
> > 
> > Regards,
> > Christoph
> > 
> > --
> > Christoph Paasch
> > PhD Student
> > 
> > IP Networking Lab --- http://inl.info.ucl.ac.be
> > MultiPath TCP in the Linux Kernel --- http://inl.info.ucl.ac.be/mptcp
> > Université Catholique de Louvain
> > 
> > www.rollerbulls.be
> > --
> > --
> > To unsubscribe from this list: send the line "unsubscribe netdev" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html

--
Christoph Paasch
PhD Student

IP Networking Lab --- http://inl.info.ucl.ac.be
MultiPath TCP in the Linux Kernel --- http://inl.info.ucl.ac.be/mptcp
Université Catholique de Louvain

www.rollerbulls.be
--