Re: [dtn-users] MSFC DTN2 Patches - 2016-02-29

Hi David,

I found some time earlier to test the MSFC patches and LTPUDP on my Pi test
bed, info below.

Installation / Patching:
Everything installed and patched fine using the instructions in the
documentation.
There was one very small modification required to apply the arm patch:

patch –p 1 –i atomic-armv7.patch

should be:

patch –p 1 –i atomic_armv7.patch

General feedback:
- Configuration file is easy to understand and use
- I like the option to automatically rotate log files and also stop the db
logs from filling up /tmp
- It seems to make good use of available RAM/CPU automatically using the
default configuration
- Previously using DTN2/LTPlib, I needed to add a pause between bundle
transmissions to achieve 100% delivery ratio, however I did not need to do
that with any of my tests using LTPUDP

Experiments carried out:
I sent 100 x 63K bundles from tx to rx, under various simulated network
conditions.
The default configuration parameters worked well for all simulations apart
from those with long latency and high loss.

In one scenario I apply an 11% loss over a 20s latency, with the rate
limited to 4Mbit. In this scenario, using the default config (below), I
observed a lot of cancellation segments and also some LTP Protocol errors
in the network captures.
It may have achieved 100% delivery ratio eventually, but I cut it short as
it seemed to be taking too long.

set remote_rate 0
inact_intvl=30
retran_intvl=3
retran_retries=3
seg_size=16000
agg_size=64000

I then applied the following config changes:

set remote_rate 4000000
inact_intvl=60
retran_intvl=30
retran_retries=10
seg_size=1400
agg_size=65000

The above changes resulted in much faster delivery, a 100% delivery ratio,
much fewer cancellation segments and no LTP protocol errors.

In the next wave of experiments I will be gathering more detailed info, but
thought you might like this info now.

Kind Regards,
Nik

On Tue, Mar 1, 2016 at 10:08 PM, Zoller, David A. (MSFC-EO50)[HOSC SERVICES
CONTRACT] <david.a.zoller@nasa.gov> wrote:

> Hi Nik,
>
> Thanks for giving it a spin and I’m glad to hear that it patched and built
> successfully from the tip. My past experience has been that if I upload a
> patch then that same night changes get applied that break it which is why I
> provided a link to download the proper revision just in case. I look
> forward to learning of your results in the Pi test-bed.
>
> Best regards,
>
> DZ
>
>
>
> *From:* Nik Ansell [mailto:nikansell00@gmail.com]
> *Sent:* Tuesday, March 01, 2016 11:23 AM
> *To:* Zoller, David A. (MSFC-EO50)[HOSC SERVICES CONTRACT]
> *Cc:* dtn-users@irtf.org
> *Subject:* Re: [dtn-users] MSFC DTN2 Patches - 2016-02-29
>
>
>
> Hi David,
>
>
>
> This looks like a very interesting release.
>
>
>
> I did some quick tests using my Ubuntu 15.10 VMs running on VMWare Fusion
> and thought I'd report back on progress so far.
>
>
>
> I did a "make clean" of all previous oasys, dtn2 and (in my case) LTPlib
> installations, then downloaded, patched and installed dtn2 and oasys
> without any issues. I did deviate slightly from the build instructions as I
> used hg clone the latest builds:
>
> hg clone http://hg.code.sf.net/p/dtn/DTN2 dtn2
>
> hg clone http://hg.code.sf.net/p/dtn/oasys oasys
>
> The following tests completed successfully without any issues. (There were
> no network simulations between the nodes): UDPCL (100 x 63k bundles), TCPDL
> (100 x 1M bundles), LTPUDP (100 x 63K bundles).
>
> I used the default settings for all LTPUDP link parameters and it seemed
> very fast.
>
> I will run the same tests through some network simulations on my Pi
> test-bed at some point soon and report back how I get on.
>
>
> Kind Regards,
> Nik
>
>
>
> On Tue, Mar 1, 2016 at 6:34 AM, Zoller, David A. (MSFC-EO50)[HOSC SERVICES
> CONTRACT] <david.a.zoller@nasa.gov> wrote:
>
> Greetings all,
>
> I have uploaded a new set of DTN2 patches to the Sourceforge site:
>
> https://sourceforge.net/p/dtn/patches/8/
>
>
>
> These patches contain the modifications used in operations at Marshall
> Space Flight Center (MSFC) in support of the International Space Station
> and several recent additions that will be rolled into it in the future.
> MSFC hosts a DTN2 based gateway node on the ground that communicates via
> LTP over UDP with an onboard ION gateway node to provide DTN capabilities
> to payloads.
>
> Included are:
>
> ·         Performance improvements
>
> ·         IPN Scheme support fixes and enhancements
>
> ·         LTP over UDP (LTPUDP) Convergence Layer
>
> ·         LTPUDP with LTP Authentication extensions
>
> ·         STCP Convergence Layer (ION innovation)
>
> ·         External Router enhancements and our EHS Router
>
> ·         Extended Class of Service support (only EHS Router makes use of
> it for routing decisions)
>
> ·         Aggregate Custody Signal support
>
> ·         Delay Tolerant Payload Conditioning
>
>
>
> Also included in this release are updates to the DTN and LTP Wireshark
> dissectors. The updated dissectors are uploaded here for those that would
> like to build from the Wireshark source code. They will also be uploaded to
> wireshark.org soon.
>
>
>
> Thanks for giving them a try and please let me know if you run into any
> issues,
>
> DZ
>
>
>
> David Zoller
>
> COLSA Corporation
>
> Marshall Space Flight Center
>
>
>
>
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>