On Sun, 7 Apr 2002, Michael Richardson wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> >>>>> "jamal" == jamal <hadi@xxxxxxxxxx> writes:
> >> -IFOP_DOWN_LOWERLAYER
> >> Lower layer is down, f.e. ethernet interfaces below a VLAN
> >> -IFOP_DOWN_NOCARRIER
> >> Interface link beat/framing is missing (current netif_carrier_o* maps
> >> here)
> Are there docs on these interfaces somewhere?
I guess this discussion will result in some documentation...
> jamal> Good naming convention for the above two.
> >> -IFOP_DOWN_KEEPALIVE
> >> Another form of keepalive is missing
> jamal> Not clear on this one.
> PPP, for instance, does keepalives.
> An IPsec tunnel might also use such a mechanism (we have plans).
Well, in that case the device is actually IFOP_UP. And the keepalives
could be looked at as "carrier/link level diagnostics". Should the
heartbeats disappear, it would be fair to transition the device to
IFOP_DOWN_NOCARRIER. Should the device underneath have its carrier
dissapear (eg a cable removed on an ethernet which ipsec0 uses), then
the transition is very quickly to IFOP_DOWN_LOWERLAYER.... I guess the
device(ipsec0) may also transition to IFOP_DOWN_NOCARRIER since its
carrier path is doewn etc.
> jamal> Also the only time IFOP_DOWN_LOWERLAYER makes sense is when the top
> jamal> stacked device is actually admin up (but none of the lower devices
> jamal> operationally UP)
> There are very good operational reasons why this is often done...
> It would be nice to see this kind of stuff in diagnostics.
I think they should be accessible; whether you send netlink
advertisements everytime there is some state transition is the question.
In my opinion the only interesting things are the a transition from a case
where a carrier (ethernet cable) is connected to where it is disconnected.
The other direction is also important. For example, i think these are the
only two route daemons need to know about.