2009/344 Bridging Updates

[Sebastien Roy]

On Fri, 2009-06-12 at 11:21 -0400, James Carlson wrote:
> Sebastien Roy writes:
> > Only one request for clarification:
> > 
> > On Mon, 2009-06-08 at 13:47 -0400, James Carlson wrote:
> > >   - /dev/bridge/ is gone
> > > 
> > >     This is no longer needed; Clearview's /dev/net/ observability
> > >     nodes serve all the needs of the bridging design.
> > 
> > There is some inconsistency at least in the specification (I assume that
> > the implementation works).  /dev/net nodes are not observability nodes,
> > but full-fledged DLPI link nodes.
> 
> Sorry about the nomenclature.
> 
> Yes, they're "real" DLPI link nodes, using plain old Ethernet, with
> the exception that they're not treated as bridge links and you can't
> transmit on them.  Both the design and the 'bridging-spec.txt'
> architectural document cover this.

That's what I thought.

> 
> >  /dev/ipnet nodes are IP observability
> > nodes.
> 
> Right; we're not using those at all.  We're not delivering IP changes.

Indeed.

> >  The new materials state:
> > 
> > +    using the /dev/net/ facility implemented for "Clearview: IP
> > +    Observability Devices" (PSARC 2006/475).  These nodes will be
> > +    named by the bridge name plus a trailing "0".
> > 
> > /dev/net nodes were added by 2006/499, and /dev/ipnet nodes by 2006/475.
> > The inconsistency should be fixed in the spec.
> 
> Ah, ok.  Sorry about that; I somehow thought they were all one thing.
> (See?  I said before that I was confused about these two classes of
> nodes ...)

I think that the BPF project's general solution to this kind of problem
is quite slick (one device, with a mechanism to specify the "layer" at
which the consumer wishes to operate).  The BPF and PF_PACKET
functionality will eventually make /dev/ipnet obsolete, thus hopefully
removing the confusion.

> 
> Consider the reference updated.

Excellent, thanks.  +1

-Seb