Re: [multipathtcp] Adding a new work item on MPTCP API

Olivier Bonaventure <Olivier.Bonaventure@uclouvain.be> Wed, 09 November 2016 15:31 UTC

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To: philip.eardley@bt.com, multipathtcp@ietf.org
From: Olivier Bonaventure <Olivier.Bonaventure@uclouvain.be>
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Date: Wed, 9 Nov 2016 16:30:59 +0100
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Subject: Re: [multipathtcp] Adding a new work item on MPTCP API
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Phil,

> Following the earlier discussion, there is support to add a charter item
> as follows:
>
> <<RFC6897 defined an optional, basic application interface for
> MPTCP-aware applications, including a set of socket operations. Now
> there is more experience of how MPTCP is being used, the WG will
> re-visit this work, and consider adding more advanced socket operations.
> The document will be Informational.>>
>
> If you disagree with this being added, or suggest some mod to this item,
> please say.

Fine for me. When RFC6987 was published, nobody had experience with an 
API for MPTCP. With the existing deployments, there is experience with 
such APIs and it makes sense to define an API that would allow 
applications to interact with an MPTCP stack. The availability of such 
an API will be very important for those who want to deploy MPTCP 
end-to-end. There are various use cases where it makes sense for an 
application to control the utilisation of the underlying subflows and 
the WG should support those use cases.

When MPTCP was designed, we refrained from doing any modification to the 
socket API to ensure that it could be incrementally deployed and support 
existing application. Looking at the largest deployment, it turns out 
that this deployment is an application that does a clever utilisation of 
the underlying MPTCP stack and not a generic application that simply 
runs on top of MPTCP...

We should probably start the work by looking back at RFC6897 and examine 
which parts of this document have been implemented or can be implemented 
and which parts should be updated based on the operational experience.


Olivier