Re: Suggestion for /proc/net/dev: Additional field "Bandwidth"

Rolf Fokkens (rolf@flits102-126.flits.rug.nl)
Sat, 07 Nov 1998 20:55:26 +0100


Alan Cox wrote:

> > This is my suggestion: add a field Bandwidth (max bytes/sec) to
> > /proc/net/dev. It shouldn't be too hard (I guess), and it's a very
> > relevant attribute of an interface, especially when interfaces can
> > operate in both 100Mbit and 10Mbit.
>
> Why does the kernel need to care. Surely bandwidth is something the user
> side should configure - in fact only user space (chat in paticular) knows
> the negotiated modem speed

There's no use for the kernel itself, but wether it's a modem device, an
isdn device or an ethernet device: the kernel is the common factor. In some
cases the driver (10Mbit or 100Mbit ethernet, ISDN, part of the kernel)
knows, and sometimes a userprogram (chat, userspace) knows.

Taking a functional-only look at this matter: Bandwidth is a device
attribute, and the kernel is common to all devices. So it could be
convenient if the kernel could tell the bandwidth.

Though I don't have much examples of applications of the bandwidth attribute
(only one: my own NetMon program) I can imagine there might me more
applications for a bandwidth attribute in userspace.

Taking a technical look at the matter: It shouldn't be so very hard, though
I'm told some ethernet devices don't know at what speed
(10Mbit/100Mbit) they operate, so the driver can't specify this in
/proc/net.

Another concern is that 2.2 isn't there yet, so it's not too late ;-)

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