Default bandwidth

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Andria Trigeorgi

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Aug 28, 2021, 4:14:33 AM8/28/21
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Hi, 

Could you tell me the default  bandwidth on physical nodes? 

Thank you in advance, 

Andria 

Mike Hibler

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Aug 28, 2021, 1:37:38 PM8/28/21
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What bandwidth are you referring to? Network bandwidth? That can vary from
100Mb to 10Gb depending on the node type. See:

http://docs.emulab.net/hardware.html
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Andria Trigeorgi

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Aug 28, 2021, 2:04:52 PM8/28/21
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I am referring to the default traffic shaping parameters between nodes.

> On 28 Aug 2021, at 8:37 PM, Mike Hibler <mi...@flux.utah.edu> wrote:
>
> What bandwidth are you referring to? Network bandwidth? That can vary from
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Eric Eide

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Aug 28, 2021, 5:54:02 PM8/28/21
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Andria Trigeorgi <an.tri...@gmail.com> writes:

> I am referring to the default traffic shaping parameters between nodes.

I think you might have a minunderstanding about how Emulab works.

When you request resources from Emulab --- in other words, when you
"instantiate a profile" --- Emulab gives you isolated, *physical* compute nodes
and network links. Emulab does not give you virtual nodes and links unless you
specifically ask for virtual resources.

This is why Mike Hibler pointed you to the documentation on the hardware.
http://docs.emulab.net/hardware.html

The different kinds of hardware nods have different kinds and speeds of network
interfaces. They vary from 100Mbps to 10Gpbs.

Emulab doesn't do traffic shaping on the network links that it allocates to you
for your experiment. Again, this is something you can *ask* for, but by
default, Emulab does not impose "traffic shaping parameters between nodes."

I hope that this is helpful!

Eric.

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Eric Eide <ee...@cs.utah.edu> . University of Utah School of Computing
https://www.cs.utah.edu/~eeide/ . +1 801-585-5512 . Salt Lake City, Utah, USA

Andria Trigeorgi

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Aug 28, 2021, 6:48:46 PM8/28/21
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> On 29 Aug 2021, at 12:54 AM, Eric Eide <ee...@cs.utah.edu> wrote:
>
> Andria Trigeorgi <an.tri...@gmail.com> writes:
>
>> I am referring to the default traffic shaping parameters between nodes.
>
> I think you might have a minunderstanding about how Emulab works.
>
> When you request resources from Emulab --- in other words, when you
> "instantiate a profile" --- Emulab gives you isolated, *physical* compute nodes
> and network links. Emulab does not give you virtual nodes and links unless you
> specifically ask for virtual resources.

Hello,

Thank you for your response!! Yes I have requested a Lan with RawPC nodes of d400 type. I have seen that I can specify the traffic shaping parameters for each of the node in the Lan (e.g. by setting value to request.LAN(“lan”).bandwidth etc). So I am wondering about the default value for bandwidth, latency, packet loss.
>
> This is why Mike Hibler pointed you to the documentation on the hardware.
> http://docs.emulab.net/hardware.html
>
> The different kinds of hardware nods have different kinds and speeds of network
> interfaces. They vary from 100Mbps to 10Gpbs.
>
> Emulab doesn't do traffic shaping on the network links that it allocates to you
> for your experiment. Again, this is something you can *ask* for, but by
> default, Emulab does not impose "traffic shaping parameters between nodes."
>
> I hope that this is helpful!
>
> Eric.
>
> --
> -------------------------------------------------------------------------------
> Eric Eide <ee...@cs.utah.edu> . University of Utah School of Computing
> https://www.cs.utah.edu/~eeide/ . +1 801-585-5512 . Salt Lake City, Utah, USA
>
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Mike Hibler

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Aug 28, 2021, 8:46:12 PM8/28/21
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If you do not specify an explicit bandwidth for a link, you get a "native
speed" link, which for the d430s could be either 1Gb or 10Gb since these
machines have both 1Gb and 10Gb NICs. Which you get depends on the specific
nodes available at the time and the heuristics of the mapping algorithm.
You can specify a bandwidth of one or the other to ensure you get a native
link at the desired speed.

"Traffic shaping" is a different mechanism that was intended for BWs that
don't match the native speed (or if you need to induce delay or packet loss).
However, for bandwidth, it only works well for BWs of less than 100Mbs.

On Sun, Aug 29, 2021 at 01:48:41AM +0300, Andria Trigeorgi wrote:
>
>
> > On 29 Aug 2021, at 12:54 AM, Eric Eide <ee...@cs.utah.edu> wrote:
> >
> > ???Andria Trigeorgi <an.tri...@gmail.com> writes:
> >
> >> I am referring to the default traffic shaping parameters between nodes.
> >
> > I think you might have a minunderstanding about how Emulab works.
> >
> > When you request resources from Emulab --- in other words, when you
> > "instantiate a profile" --- Emulab gives you isolated, *physical* compute nodes
> > and network links. Emulab does not give you virtual nodes and links unless you
> > specifically ask for virtual resources.
>
> Hello,
>
> Thank you for your response!! Yes I have requested a Lan with RawPC nodes of d400 type. I have seen that I can specify the traffic shaping parameters for each of the node in the Lan (e.g. by setting value to request.LAN(???lan???).bandwidth etc). So I am wondering about the default value for bandwidth, latency, packet loss.
> >
> > This is why Mike Hibler pointed you to the documentation on the hardware.
> > http://docs.emulab.net/hardware.html
> >
> > The different kinds of hardware nods have different kinds and speeds of network
> > interfaces. They vary from 100Mbps to 10Gpbs.
> >
> > Emulab doesn't do traffic shaping on the network links that it allocates to you
> > for your experiment. Again, this is something you can *ask* for, but by
> > default, Emulab does not impose "traffic shaping parameters between nodes."
> >
> > I hope that this is helpful!
> >
> > Eric.
> >
> > --
> > -------------------------------------------------------------------------------
> > Eric Eide <ee...@cs.utah.edu> . University of Utah School of Computing
> > https://www.cs.utah.edu/~eeide/ . +1 801-585-5512 . Salt Lake City, Utah, USA
> >
> > --
> > You received this message because you are subscribed to the Google Groups "emulab-users" group.
> > To unsubscribe from this group and stop receiving emails from it, send an email to emulab-users...@googlegroups.com.
> > To view this discussion on the web visit https://groups.google.com/d/msgid/emulab-users/m1y28lfd71.fsf%40cs.utah.edu.
>
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Andria Trigeorgi

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Aug 28, 2021, 11:31:02 PM8/28/21
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Thank you very much! Could you tell me what is the bandwidth when I use XenVM nodes instead of RawPC?

Leigh Stoller

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Aug 29, 2021, 6:38:28 AM8/29/21
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at 8:30 PM, Andria Trigeorgi <an.tri...@gmail.com> wrote:

> Thank you very much! Could you tell me what is the bandwidth when I use XenVM nodes instead of RawPC?

Hi. The default is 100Mb for XEN VMs.

Leigh

Andria Trigeorgi

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Aug 29, 2021, 6:57:12 AM8/29/21
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Thank you all for your help!!

Andria

> On 29 Aug 2021, at 1:38 PM, Leigh Stoller <lbst...@gmail.com> wrote:
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Gautam Thaker

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Aug 29, 2021, 10:31:17 AM8/29/21
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Here is my $0.02 worth from my yesterday's tests using 2 d430s. I checked, I had 10Gbps  interfaces. I did  various tests of round-trip message latencies and bandwidth I see.

Here is 1 result. I sent 1E7 msgs of size 64Kbytes from one d430 to another w/ each msg ack'ed by 1 byte msg. I measured roundtrip latency and attached histogram shows the result. I need to trace down where the 2nd hump comes from - but over all I see about 2.5 Gbps thruput (would be prob higher as this is RT test.)

Gautam
64K_1e7_d430s_latencies.png

Leigh Stoller

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Aug 31, 2021, 8:26:53 AM8/31/21
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at 10:31 AM, Gautam Thaker <ghth...@gmail.com> wrote:

> Here is 1 result. I sent 1E7 msgs of size 64Kbytes from one d430 to another w/ each msg ack'ed by 1 byte msg. I measured roundtrip latency and attached histogram shows the result. I need to trace down where the 2nd hump comes from - but over all I see about 2.5 Gbps thruput (would be prob higher as this is RT test.)

Hi. Try doing an iperf test with the -P option set to something like 6.
A single iperf thread typically cannot saturate a 10G link.

Leigh


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