[ECOS] Re: SNMP lockup

Grant Edwards grante@visi.com
Sat May 9 08:48:00 GMT 2009


On 2009-05-08, Gary Thomas <gary@mlbassoc.com> wrote:

>>> The problem occurs when cyg_snmp_get_if() is called with if_num <= 0.
[...]
>>> I'm surprised nobody else has run into this.  I'm told all our
>>> customers who have HP or Cisco SNMP managers have had to
>>> disable SNMP support in our products to keep them from locking
>>> up every few minutes.
>> 
>> I was just googling +'ifPhysAddress.0'
>> 
>> It seems you are not alone :-)
>> 
>> http://mtsc.moxa.com:8888/Software/DN/NPort/Firmware/NPort%205000/NPort%205600/ver3.2/VERSION.TXT

That's interesting -- I hadn't found that.  Since the bug was
in eCos-specific code, do we assume that Moxa is using eCos for
the NPort?

>> UCD-SNMP had a lot of holes. eCos UCD-SNMP implementation has
>> even more holes :-(

Um... I blame Dick Cheney and Karl Rove!

> Feel free to improve this

Workin' on it...

> - much of the networking code, including SNMP, is more than
> seven (7!) years old.  A lot has gone on in the world in that
> time...

What I'd like a pointer on is the interface numbering in SNMP
OIDs.  Are the interfaces supposed to be numbered 1..N with
interface 0 being non-existent?  Or are eCos interface numbers
off by one and they should really be 0,1 instead of 1,2? [I
tried looking through the OID/ASN.1 docs, but got lost rather
quickly.]

If SNMP interface numbers are supposed to start at #1, why do
HP and Cisco SNMP managers ask for attributes of interface #0?

I looked at network traces for one customer site using, I
believe, HP Insight. It does read the interface attributes for
interfaces 1 and 2.  I don't see it attempt to read attributes
for interface 3 (which doesn't exist). I do see it attempt to
read attributes for interface 0 (which also doesn't exist).

If interface numbers are supposed to start at #0, will
renumbering the interfaces at this point (after product has
been shipping for 7 years) cause more problems that it will
solve?

-- 
Grant



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