Re: [PATCH 0/9] isdn4linux: add drivers for Siemens Gigaset ISDN DECT PABX

[Stephen Hemminger <shemminger@osdl.org>]

On Mon, 19 Dec 2005 20:22:42 +0100
Tilman Schmidt <tilman@imap.cc> wrote:

> On 2005-12-19 18:01, Lee Revell wrote:
> > On Mon, 2005-12-19 at 17:38 +0100, Tilman Schmidt wrote:
> > 
> >>Unfortunately these don't fit our needs, as we are not dealing with a
> >>network device, but with an ISDN device.
> > 
> > Um, isn't that what the N in ISDN stands for?
> 
> While the ISDN is indeed called a network, devices connecting a computer
> to it are nevertheless not commonly referred to as network devices.
> 
> > I guess what you mean is that although ISDN devices are obviously
> > networking devices, the kernel uses a separate subsystem for ISDN?
> 
> There's more to it than that. The notion of a "network" is a rather
> broad one, including such diverse phenomena as Ethernet, ISDN, TV cable
> or even roads or TV stations. The notion of a "network device", on the
> other hand, is a quite specific one, at least in the computer world, and
> it certainly doesn't include ISDN TAs.
> 
> In fact, the operation of an ISDN device is much closer to a modem or
> even an answering machine than to that prototypical network device which
> is the Ethernet card. This is of course the reason why the Linux kernel
> puts them in a subsystem of their own. Making them net_device-s just
> wouldn't work.
> 


My definition is simple. Any device driver that exports a netdevice
interface needs to be reviewed on netdev to make sure the assumptions
about network device semantics are being followed.

-- 
Stephen Hemminger <shemminger@osdl.org>
OSDL http://developer.osdl.org/~shemminger