Re: [multipathtcp] Two proxy scenario (network proxy off path)

["[e-mail]" <[e-mail]>]

On 29/03/17 - 16:13:18, [e-mail] wrote:
> Christoph,
> 
> If you remove the initial TCP connection,
> If you remove the authentication negotiation,
> If you include the payload of the original SYN as part of the NEW SOCKS request
> 
> You are just cloning the MP_CONVERT behavior by overloading SOCKS semantic without providing an extra feature compared to the MP_CONVERT.
> 
> For the particular case of IPv6 when source address/prefix preservation is required, I don't see how this can be supported by SOCKS. Of course, you can modify the SOCKS command to clone MP_CONVERT :) 

The point is that we should try to do something that is architecturally clean,
without being closely linked to MPTCP.

Just imagine, if you deploy a proxy that enables the use of TCP-BBR, a
congestion-control that is much better than what servers/clients currently
use. This would also need a 0-RTT proxying solution (even if it is not
using MPTCP).


The point I am trying to make is that a 0-RTT proxying solution is not
something that the MPTCP working-group should be in charge of. There are
other places in the IETF that are probably more appropriate for this.


Christoph

> 
> Cheers,
> Med
> 
> > -----Message d'origine-----
> > De : [e-mail] [mailto:[e-mail]]
> > Envoyé : mercredi 29 mars 2017 10:47
> > À : Henderickx, Wim (Nokia - BE/Antwerp)
> > Cc : [e-mail]; BOUCADAIR Mohamed IMT/OLN;
> > [e-mail]
> > Objet : Re: [multipathtcp] Two proxy scenario (network proxy off path)
> > 
> > On 29/03/17 - 15:42:59, Henderickx, Wim (Nokia - BE/Antwerp) wrote:
> > > Christoph, yes but again it something new and less optimal from the
> > proposed MP_CONVERT IE in the SYN.
> > 
> > No, that's what I wrote below. It's not less optimal. It's exactly the
> > same in
> > terms of performance as MP_CONVERT IE in the SYN!
> > 
> > 
> > Christoph
> > 
> > 
> > >
> > > On 29/03/2017, 10:39, "[e-mail] on behalf of Christoph Paasch"
> > <[e-mail]> wrote:
> > >
> > >     Hello Wim,
> > >
> > >     inline:
> > >
> > >     On 29/03/17 - 15:29:04, Henderickx, Wim (Nokia - BE/Antwerp) wrote:
> > >     > Phil, you will be a bit more optimal but not a lot as you can see
> > or you end up changing the SOCKs protocol. Even if you do this MP_CONVERT
> > IE will always be the most optimal and hence this is what we propose for
> > doing this proxy function.
> > >     >
> > >     > On 29/03/2017, 10:12, "multipathtcp on behalf of
> > [e-mail]" <[e-mail] on behalf of
> > [e-mail]> wrote:
> > >     >
> > >     >     By non-chatty, I meant a version that didn't do all the
> > authentication messages. After all, the home gateway and network proxy can
> > be expected to know about each other already - at least don't need to do
> > for every new TCP connection from devices behind home gateway
> > >     >
> > >     >     -----Original Message-----
> > >     >     From: [e-mail]
> > [mailto:[e-mail]]
> > >     >     Sent: 29 March 2017 06:30
> > >     >     To: Eardley,PL,Philip,TUB8 R <[e-mail]>;
> > [e-mail]
> > >     >     Subject: RE: Two proxy scenario (network proxy off path)
> > >     >
> > >     >     Hi Phil,
> > >     >
> > >     >     Can you please clarify what you mean by a "non-chatty
> > version"? version of what?
> > >     >
> > >     >     You can refer to Section 3 of RFC1928 to have an idea about
> > the number of messages that are required before sending actual traffic
> > when SOCKSv5 is used.
> > >     >
> > >     >     Below an excerpt of signaling messages observed to create an
> > initial subflow using SOCKSv5:
> > >     >
> > >     >     ==============
> > >     >     (MP Client) ->    TCP SYN    ->  (MCP)
> > >     >                        <- TCP SYN/ACK <-
> > >     >                        ->    TCP ACK    ->
> > >     >                        -> SOCKS Method Request (1)(a) ->
> > >
> > >     you would of course use TFO with SOCKS, so that you gain one RTT.
> > >
> > >     If then in addition to that you remove the authentication part of
> > SOCKS, and
> > >     you can even put the payload right after the SOCKS Connection
> > Request inside
> > >     the SYN-payload, then you are effectively also at a 0-RTT connection
> > >     establishment.
> > >
> > >
> > >     Christoph
> > >
> > >
> > >     >                        <-    TCP ACK (b)   <-
> > >     >                         <- SOCKS Method Response (2)(c) <-
> > >     >                         ->   TCP ACK (d)   ->
> > >     >                         -> SOCKS Authentication Request (3)(e) ->
> > >     >                         <-    TCP ACK (f)    <-
> > >     >                         <- SOCKS Auth. Response (4)(g) <-
> > >     >                         ->   TCP ACK (h)   ->
> > >     >                         -> SOCKS Connection Request (5)(i) ->
> > (MCP)
> > >     >                         <-   TCP ACK (j)                   <-
> > (MCP)
> > >     >
> > (MCP)  -> TCP SYN (k) -> (Server)
> > >     >
> > (MCP)  <- SYN/ACK (l) <- (Server)
> > >     >                         <- SOCKS Connection Response (n) (6) <-
> > (MCP) -> TCP ACK (m) -> (Server)
> > >     >                         ->   TCP ACK (o)  ->
> > >     >     =================
> > >     >
> > >     >     I let you compare it with the 0-RTT and 0-extra signaling
> > approach with MP_CONVERT IE.
> > >     >
> > >     >     Cheers,
> > >     >     Med
> > >     >
> > >     >     > -----Message d'origine-----
> > >     >     > De : multipathtcp [mailto:[e-mail]] De
> > la part de
> > >     >     > [e-mail] Envoyé : mardi 28 mars 2017 20:24 À :
> > >     >     > [e-mail] Objet : [multipathtcp] Two proxy
> > scenario
> > >     >     > (network proxy off path)
> > >     >     >
> > >     >     > Hi,
> > >     >     >
> > >     >     > I'm now thinking about the scenario where there are two
> > proxies, one
> > >     >     > in the home gateway or Customer Premises Equipment and one
> > in the
> > >     >     > network, both under the control of the operator. And looking
> > at the 'explicit mode'
> > >     >     > scenario, which - if I get it right - means that the network
> > proxy is
> > >     >     > not on the default path. (It's safe to assume that the home
> > gateway
> > >     >     > proxy is on the default path)
> > >     >     >
> > >     >     > Thinking about the use of SOCKS in this context.
> > >     >     >
> > >     >     > Earlier Olivier said (in the context of the smartphone
> > scenario -
> > >     >     > sorry if your comments don't apply to this scenario and I'm
> > just
> > >     >     > creating
> > >     >     > confusion) that there are different variants of SOCKS that
> > can be
> > >     >     > used, which mainly depend on the number of messages that are
> > used to
> > >     >     > authenticate.
> > >     >     > In the two proxy scenario, it's probably reasonable to
> > assume that the
> > >     >     > home gateway and network proxy are already authenticated. So
> > a
> > >     >     > non-chatty version would be ok.
> > >     >     >
> > >     >     > Is that right?
> > >     >     >
> > >     >     > Thanks
> > >     >     > phil
> > >     >     >
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