Subject: IF-MIB (RFC 2233) Question & Errata

From: Jeff Johnson <[email-masked]>
Date: Fri, 16 Jan 1998 12:40:47 -0800 (PST)

Hi folks,

I'm looking at implementing RFC 2233 and, after reading section 3.1.15
as well as the notification descriptions, I want to verify my
interpretation of what interface notifications should be sent when a
managed device is powered up.  The description of the linkDown
notification states that it should be sent when ifOperStatus enters
the down state from any other state except for notPresent.  This is
fine for a state transition, but what about for the first poll.  If
after power-on I poll an interface and find it down, should I consider
this to be a notPresent->down or a down->down transition and do
nothing, or should I consider this to be an unknown->down transition
and issue a trap?

Similiarly, the linkUp trap is supposed to be sent when an interface
transitions out of the down state into any other state other than
notPresent.  If after power-on I poll an interface and find it up,
should I consider this to be a notPresent->up or unknown->up
transition and do nothing, or should I consider it to be a down->up
transition and issue the trap.

I guess the two questions would be answered by the question:  what is
the initial ifOperState of an interface?

I also want to verify my interpretation that down->unknown and
down->lowerLayerDown ifOperState transitions should produce a linkUp
trap (Not that I would expect to encounter the first of these in
practice, and the second case would only come in to play if
ifLinkUpDownTrapEnable were enabled on a higher layer interface).

Now for some errata:
1) The DESCRIPTION clause of the linkUp notification refers to it as
linkDown.

2) The DESCRIPTION clause for GROUP ifHCPacketGroup in the
ifCompliance2 compliance statement is incorrect.  The speed limit
specified is actually applicable to the ifVHCPacketGroup.  Further,
GROUP ifVHCPacketGroup was omitted from the compliance statement.
In other words, there are three PacketGroups defined, but only two
referenced in the compliance statement.

thanks
/jeff

---

From: Keith McCloghrie <[email-masked]>
Date: Sun, 1 Mar 1998 15:52:48 -0800 (PST)

Jeff,

[Sorry for the long delay in responding.]

> the initial ifOperState of an interface?
 
The linkUp/linkDown traps were first defined in RFC 1067.  I don't
believe the intent of RFCs 1573 & 2233 is to change their usage at
system startup.  Common practice in agents is to send only linkUp
traps at reboot, right ?  If so, it would seem that the initial
ifOperState of an interface is 'down'.

> ifLinkUpDownTrapEnable were enabled on a higher layer interface).

That's consistent with what it says.

> Now for some errata:

Thanks for the errata.  I'll save that for the next revision.

Keith.