[f-nsp] Netiron 5.6 feedbacks

[John W. O'Brien]

On 8/14/14 9:01 PM, John W. O'Brien wrote:
> On 8/12/14 4:25 AM, Youssef Bengelloun-Zahr wrote:
>> Hello,
>>
>> Has anyone tried it yet ? I was planning to do so when I come back next
>> week but any early feedbacks will be appreciated.
>>
>> Best regards.
> 
> This week we upgraded five MLXe-16 routers in our core from 5.4.00d* to
> 5.6.00d. It looks like there is an sFlow export regression in this code
> that we didn't pick up during our lab validation. At least one obvious
> problem I've identified so far by looking at raw sFlow data is that the
> input and output packet counters are lower by about a factor of 3 than
> the corresponding counters in the CLI and in the SNMP ifXTable (which
> agree with each other). We've contacted Brocade and I would be glad to
> follow up here when we resolve the issue.
> 
> I'm really hoping we can solve it without another hit-full code change.
> 
> * Actually a CVR with a work-around for DEFECT000508412---the main
> reason we chose to upgrade---which is fixed in 5.6.00d.

We've finally made progress on this issue, with the help of our flow
collector vendor. It seems likely that this is a regression in the SNMP
IF-MIB, not in the sFlow emitter. The flow collector would use the SNMP
counters to scale the sampled flows, so if the counters report bad data,
the scaling is all wrong. We've disable the SNMP scaling as a
work-around, and are continuing to work the case with Brocade.

Here's an example of what to look for, in case your flow collector or
NMS reports funky results.

Arrival Time: Sep 26, 2014 06:24:42.342790184 EDT
IF-MIB::ifHCOutOctets.970 (1.3.6.1.2.1.31.1.1.1.10.970): 0
--
Arrival Time: Sep 26, 2014 06:29:42.342692072 EDT
IF-MIB::ifHCOutOctets.970 (1.3.6.1.2.1.31.1.1.1.10.970): 0
--
Arrival Time: Sep 26, 2014 06:34:42.366492840 EDT
IF-MIB::ifHCOutOctets.970 (1.3.6.1.2.1.31.1.1.1.10.970): 0
--
Arrival Time: Sep 26, 2014 06:39:42.340412560 EDT
IF-MIB::ifHCOutOctets.970 (1.3.6.1.2.1.31.1.1.1.10.970):
6607961528840748800

IF-MIB::ifOperStatus.970 (1.3.6.1.2.1.2.2.1.8.970): down (2)
IF-MIB::ifName.970 (1.3.6.1.2.1.31.1.1.1.1.970): ethernet16/10


-- 
John W. O'Brien
Senior Network Engineer
Information Systems and Computing
University of Pennsylvania
obrienjw at upenn.edu 215-898-9818
OpenPGP key ID: 0x155016CB

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