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SubjectRe: RFC: configuring net interfaces
Ivan Passos <> writes:

> I guess 'interface' means media type (e.g. V.35, RS-232, X.21, etc.).
> Maybe it would be more intuitive to call it 'media'. What do you think?


> Also, for synchronous cards that have built-in DSU/CSU's (such as the
> Cylades-PC300/TE), it's also necessary to configure T1/E1 parameters
> (e.g. line code, frame mode, active channels, etc.). Should we make these
> parameters also available here or keep them in the driver realm?? I think
> we should have them here too, but maybe you see some problem with this
> that I don't.

No problem. That was just an example.

> > +struct hdlc_protocol /* 4 bytes */
> > +{
> > + unsigned int proto;
> > +};
> What are the possible protocols to be set here?? I imagine PPP, Cisco
> HDLC, Raw HDLC, Frame Relay, X.25, and ... ?? Is that it??


> > +struct fr_protocol /* 12 bytes */
> > +{
> > + unsigned short lmi_type;
> > + unsigned short t391;
> > + unsigned short t392;
> > + unsigned short n391;
> > + unsigned short n392;
> > + unsigned short n393;
> > +};
> So we would have hdlc_protocol->proto set to PROTO_FR, and then the
> details about Frame Relay would be set in this separate structure. Is that
> what you have in mind??

Exactly. With defaults filled in by the (some) driver.

> Maybe it's a better idea to have just two ioctl's here (GET and SET), and
> have "subioctl's" inside the structure passed to the HDLC layer (and
> defined by the HDLC layer). This would allow changes in the HDLC layer
> without having to change sockios.h (you'd still have to change HDLC's
> code and definitions, but this would be more self-contained). Again, this
> may be better, or maybe not. What do you think?

I think it would make it more complicated. ioctl namespace is huge enough.
Without changing ifmap struct size (which would require recompilation
of all programs using it - ip, ifconfig etc), the *_protocol/physical
structures can only be 16 bytes long each (8 shorts or 4 ints) - I would
rather not put command code there.

Of course, the structs I outlined are just an example, which need
checking for max and min values and then setting variable length
Krzysztof Halasa
Network Administrator
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