Subject: [multipathtcp] distribution ratio - MPTCP

From: "Koojana Kuladinithi" <[email-masked]>
Date: Wed, 17 Feb 2010 10:19:40 +0100

Hello,

I am new to mptcp. When trying to understand this concept, I was not able to
understand the following. 

If I have a huge file to download, I can use mptcp to divide this file to
several sub flows  and send them over multiple paths. When forwarding
segments to these sub flows, how to decide the ratio? - based on the path
properties/ adaptively decided based on RTT, Would it be bulk distribution
(continuous multiple segments sent over one sub flow)? 

Can somebody clarify this?

Thanks

Koojana

---

From: Sébastien Barré <[email-masked]>
Date: Wed, 17 Feb 2010 10:47:27 +0100

Hello Koojana,

Koojana Kuladinithi a écrit :
>
> Hello,
>
> I am new to mptcp. When trying to understand this concept, I was not 
> able to understand the following.
>
> If I have a huge file to download, I can use mptcp to divide this file 
> to several sub flows and send them over multiple paths. When 
> forwarding segments to these sub flows, how to decide the ratio? – 
> based on the path properties/ adaptively decided based on RTT, Would 
> it be bulk distribution (continuous multiple segments sent over one 
> sub flow)?
>
Deciding on the ratio is up to the implementation, which is why it is 
not specified in the draft.
In my current implementation (http://inl.info.ucl.ac.be/mptcp), there is 
a scheduler that decides to what subflow to send each data.
That scheduler currently does round-robin across the *available* 
subflows. By "available" I mean that the subflow has space in its 
congestion window to send the data immediately.

This should ensure filling all pipes, although correct tuning of this is 
still under investigation.

regards,

Sébastien.
> ------------------------------------------------------------------------
>
> _______________________________________________
> multipathtcp mailing list
> [email-masked]
> https://www.ietf.org/mailman/listinfo/multipathtcp
>   

-- 
Sébastien Barré
Researcher,
CSE department, UCLouvain, Belgium
http://inl.info.ucl.ac.be/sbarre

---

From: Tatiana Polishchuk <[email-masked]>
Date: Wed, 17 Feb 2010 11:57:00 +0200

Hello,
Koojana, if you are interested in the optimal multipath flow splitting
algorithm please refer to our work on HIP multipath scheduler following the
link  http://www.hiit.fi/~tpolishc/

Sincerely,
Tatiana

2010/2/17 Sébastien Barré <[email-masked]>

>> I am new to mptcp. When trying to understand this concept, I was not able
>> to understand the following.
>>
>> segments to these sub flows, how to decide the ratio? – based on the path
>>  Deciding on the ratio is up to the implementation, which is why it is not
> specified in the draft.
> In my current implementation (http://inl.info.ucl.ac.be/mptcp), there is a
> scheduler that decides to what subflow to send each data.
> That scheduler currently does round-robin across the *available* subflows.
> By "available" I mean that the subflow has space in its congestion window to
> send the data immediately.
>

---

From: Costin Raiciu <[email-masked]>
Date: Wed, 17 Feb 2010 12:08:00 +0000

Your question has two answers. First how much to send on each subflow  
is dictated by the congestion window of that subflow. How you compute  
the cwnds is another question. We propose to couple the windows across  
subflows so that the aggregate multipath throughput is the same as tcp  
on the best path.

Second answer is which segmentsgo on each subflow. Currently as seb  
says we do round robin but this could be optimized to reduce  
reordering delay at the receiver.

Cheers
Costin

On 17 Feb 2010, at 09:19, Koojana Kuladinithi <[email-masked] 
bremen.de> wrote:

> If I have a huge file to download, I can use mptcp to divide this  
> file to several sub flows  and send them over multiple paths. When  
> forwarding segments to these sub flows, how to decide the ratio? – b 
> ased on the path properties/ adaptively decided based on RTT, Would