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Date: Sat, 3 Jan 2015 18:42:07 +0100
From: Luigi Rizzo <rizzo@iet.unipi.it>
To: Slawa Olhovchenkov <slw@zxy.spb.ru>
Subject: Re: netmap pipes
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On Sat, Jan 03, 2015 at 09:32:55PM +0400, Slawa Olhovchenkov wrote:
> On Sat, Jan 03, 2015 at 06:21:39PM +0100, Luigi Rizzo wrote:
> 
> > On Sat, Jan 03, 2015 at 08:40:35PM +0400, Slawa Olhovchenkov wrote:
> > > Can anybody explain netmap pipes (more then netmap(4))?
> > > How use it?
> > > How it works?
> > > pipes works over existing network adapter in netmap mode?
> > > Or indepened (can I create netmap pipe named 'some_strange_name')?
> > > What purpose of master and slave?
> > 
> > think of pipes as regular netmap ports connected back to back,
> > (or as two ports on a VALE switch, if you like).
> > They are unrelated to network devices (though the name indicates
> > how they share memory, but forget that for the time being);
> > are created using the "strange names" like valeX:Y{0 and valeX:Y}0
> > (which I realize are not yet in the manpage, sorry);
> 
> can I use names other then valeX:Y? for example 'inside0'?

no, the basename has to be netmap:fooX (where foo is some existing
ethernet device) or valeX:Y

> > and you have master and slave because need to name both endpoints.
> 
> I create pipe with many slaves (NIOCREGIF with nr_arg1=16, for
> example), how I can use this? Writing to master replicated to all
> slaves? Writing to any slaves reading from master? Or unidirected?

a pipe has only two endpoints.

If you want a full n-port switch use a VALE switch.

cheers
luigi