perfSONAR User Q&A and Other Discussion

[Trey Dockendorf <>]

That's a problem with Linux I believe.  Having two interfaces on the same 
subnet will result in both IPs responding but if you do an arping to each IP 
you will likely see that the same MAC address is hit every time.  I do not 
know the right way to fix this, so I've always avoided that situation of 
configuring two NICs on the same subnet.

RedHat has knowledge base articles regarding this but it's for subscribers 
only.  Here's something similar but not requiring a subscription, 
http://z-issue.com/wp/linux-rhel-6-centos-6-two-nics-in-the-same-subnet-but-secondary-doesnt-ping/

Not sure if that's the problem your describing.

- Trey

=============================

Trey Dockendorf 
Systems Analyst I 
Texas A&M University 
Academy for Advanced Telecommunications and Learning Technologies 
Phone: (979)458-2396 
Email: 

 
Jabber: 


----- Original Message -----
> From: "Zhi-Wei Lu" 
> <>
> To: "Daniel Doyle" 
> <>
> Cc: 
> ,
>  "Pulak K Chowdhury" 
> <>
> Sent: Wednesday, July 30, 2014 1:56:23 PM
> Subject: RE: [perfsonar-user] tips for One way latency and bw test on 
> separate NICs on perfSonar 3.4rc2
> 
> Hi Daniel,
> 
> Thanks for the tip and I have found it configuration in the web gui.
> 
> However, I am stuck again!  I started the system with one configured
> NIC and scheduled "owamp" test.  Later, I enabled the second NIC on
> the same subnet, now the "Throughtput/Latency Graphs" won't
> displayed at all, a perpetual spinning circles goes around (even
> after I disabled the second NIC).
> 
> If I have two NICs in the the same host on the same subnet, will the
> outgoing tests use the first interface only (default route on the
> default NIC)?  While both interface were up, the "local services"
> show all tests running on both NICs, how can I configure the
> incoming tests for individual NIC.  With two NICs on the same
> subnet, the incoming test comes the second NIC, but the outgoing
> packets could be sent out on the first NIC, is that right?
> 
> Thank you.
> 
> Zhi-Wei Lu
> IET-CR-Network Operations Center
> University of California, Davis
> (530) 752-0155
> 
> -----Original Message-----
> From: Daniel Doyle 
> [mailto:]
> Sent: Wednesday, July 30, 2014 6:34 AM
> To: Zhi-Wei Lu
> Cc: 
> ;
>  Pulak K Chowdhury
> Subject: Re: [perfsonar-user] tips for One way latency and bw test on
> separate NICs on perfSonar 3.4rc2
> 
> Zhi-Wei,
> 
> This is configurable in the same place as you configure all the rest
> of the test parameters, underneath "Toolkit Administration" on the
> left in the section "Configure Tests".
> 
> There is now a new field called "Interface" under the Test Parameters
> section of a test that defaults to "Default" which was the old
> behavior. You can change this to instruct the test to use a specific
> interface instead. All previously configured tests should have
> "Default" set as their Interface option when upgrading.
> 
> Hope that helps.
> 
> -Dan
> 
> On Jul 30, 2014, at 1:47 AM, Zhi-Wei Lu 
> <>
>  wrote:
> 
> > Hi all,
> > 
> > I have successfully installed perfSonar 3.4rc2 recently and I heard
> > that it is now possible to configure owamp and bw tests on two
> > separate NICs, I would love to learn how I can configure perfSonar
> > to accomplish two NIC set up.
> > 
> > Thank you very much for your help.
> > 
> > --
> > Zhi-Wei Lu
> > IET-CR-Network Operations Center
> > University of California, Davis
> > (530) 752-0155
> 
> Dan Doyle
> GlobalNOC Software Developer
> 1-812-856-3892
> 
> 
> 
> 
>