Re: [multipathtcp] New Version of MPTCP Architecture Draft

Hello Alan, 

I have several questions on the reliability section.
Could you elaborate a bit?

In section 4.2, you mentioned that there are currently no connection 
levels acks. However, after a few lines later, you also mentioned connection
level MPTCP ACKs are not cumulative. Isn't it contradictionary?

If connection level MPTCP ACK exists, what does it look like? Why it cannot
be cumulative? 

".. The receiver can simply drop out-of-order segements if needed (for instnace,
due to memory pressure)."  Could you elaborate how this situation happens?

".. if the proxy acks a segment and then crashes, the sender will not retransmit
the lost segment on another subflow." To deal with this case, I think MPTCP 
needs to keep data for a while even if it is acked by subflow. But, it looks 
very expensive. Do we need to support this?

Thanks,
--
Yoshifumi Nishida
nishida@sfc.wide.ad.jp

From: "Ford, Alan" <alan.ford@roke.co.uk>
Subject: [multipathtcp] New Version of MPTCP Architecture Draft
Date: Wed, 3 Feb 2010 11:03:24 -0000
Message-ID: <2181C5F19DD0254692452BFF3EAF1D68095EDC61@rsys005a.comm.ad.roke.co.uk>

 > Hi all,
 > 
 > We have submitted an updated version of the MPTCP architecture draft,
 > which can be found at:
 > http://www.ietf.org/id/draft-ford-mptcp-architecture-01.txt
 > 
 > This is a significant change from the previous version, concentrating
 > now on how core architectural principles will lead to high-level design
 > decisions for a MPTCP protocol.
 > 
 > It is intended to present and discuss this draft at the interim audio
 > conference next week. In the meantime, we'd be very interested in
 > feedback and discussion, so please do send comments to the list.
 > 
 > Cheers,
 > Alan
 > 
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