[j-nsp] SNMP interface index change after upgrade to 9.2

[Tore Anderson]

* Richard A Steenbergen

> Normally I'm the one yelling at Juniper when they do something stupid
> and break things for no reason, but honestly...

I admit that the tone in my first e-mail to this thread was over the
line, and for that I do apologise.  I hope nobody got offended.

It was extremely frusterating to spend much of the day cleaning up the
unexpected graph mess that resulted from the JUNOS upgrade - I certainly
had more interesting tasks planned.  Hearing from Malte that the issue
had already been reported to JTAC, but that they didn't seem to care,
made me quite angry and upset.  I should have kept my breath for ten
seconds before replying, though.

I do appreciate that Patrik is looking into the issue now.

> Any software which relies on static ifIndex mappings between polling
> cycles is fundamentally flawed, period, end of discussion. There is
> absolutely no excuse for this, it is beyond trivial to map data by
> ifDescr, and the SNMP spec even tells you that ifIndex is not to be
> used for this kind of thing.

I realise that now.  However, such pieces of software are in use by many
people (five people in this thread alone as far as I can see), and when
the ifIndex changes, it causes severe breakage for us.

Even though current JUNOS behaviour can be considered spec-compliant I
would still like to see the ifIndexes being kept static - it would be a
great feature enhanchement for those of us that (unwittingly) chose SNMP
software that doesn't handle ifIndexes changing.  As I pointed out in my
first message, it can't be that hard - just reserve some space for the
private ifIndexes and start the public ones from, say, 1000.  (This is
what my Extreme switches does.)

Speaking of Extreme, by the way...  Juniper is the first vendor whose
gear has changed ifIndexes on me, ever.

> I really don't understand why people still can't figure out how to do
> this.

I assume most of the people on this list are not application developers,
but network administrators - at least I am not.  So I/we are stuck with
whatever pieces of software is available, and changing an already-
established setup is probably going to be a big project in most cases.
Considering that not even the ubiquitous MRTG handles changing ifIndexes
by default I think static ifIndexes would be a worthwhile feature for
Juniper to implement in an upcoming JUNOS release.

Best regards,
-- 
Tore Anderson
Redpill Linpro AS - http://www.redpill-linpro.com/