[USRP-users] Netgear 10GB switch XS728T

Kevin Krieger kevin.krieger at usask.ca
Mon Oct 30 13:30:32 EDT 2017

Hi Marcus,

I finally got around to this.
I've attached 9 captures.

The setup for the captures was:
XS728T with latest firmware running, factory default
Computer running tx_bursts has IP of or .67
N200 has IP of
  ./tx_bursts  --args addr0=  --freq 10e6 --rate 1e6

Captures 0,1 and 2 are with both the ports (n200 side, and computer 
side) mirrored to the wireshark capture port, so you essentially see 
duplicate traffic.
Captures 3,4 and 5 are with only the computer side traffic captured
Captures 6,7 and 8 are with only the N200 side traffic captured.

Captures 0, 4, and 8 are with the messages "Sent packet: 363 samples" 
appearing, but then the "Waiting for async burst ACK ... fail" message 
also appears.
Captures 1, 3 and 7 are with the message :Error: Runtimeerror: fifo ctrl 
timed out looking for acks" appearing.
Captures 2, 5 and 6 are with successful runs of the tx bursts program, 
so instead of 'fail' at the end there is 'success'.

There are txt files with the output of the program for each capture, as 
well as csv files showing the dissected output (only found uhd in the 

Can you see anything wrong with these runs? Any help is appreciated.


On 06/15/2017 02:28 PM, Kevin Krieger via USRP-users wrote:
> Hi Marcus,
> Thank you - I was sure that the same subnet was correct but it's good 
> to have confirmation.
> I have done the dissecting previously, and I recall getting a bunch of 
> "huh what's that?"' messages and then a 'wassup bro' or something but 
> I'll do it again and let you know what I see. (Hilarious descriptions 
> btw!)
> Kevin
> On 05/24/2017 08:07 PM, Marcus Müller via USRP-users wrote:
>> Hi Kevin, Hi Robin,
>> the same-subnet configuration is the right one, here. There's no 
>> routing ambiguity if you have one card that serves the whole switch.
>> Kevin, this might be much to ask, but: I'd ask you to both install 
>> wireshark and its development headers (typically, wireshark-dev or 
>> wireshark-devel) from your operating system's package manager.
>> Then, get the UHD source code, and
>> cd /path/to/uhd/tools/dissectors
>> mkdir build
>> cd build
>> cmake -DETTUS_DISSECTOR_NAME=zpu ..
>> make -j4 && make install
>> Ideally, add your user to the group that has access to the raw 
>> network hardware (in case of my OS, that was the "wireshark" group), 
>> log out and back in.
>> If that doesn't work, you have to record as root and analyze as your 
>> user (the USRP protocol dissectors got installed to your home directory).
>> Then, record the traffic on your 10G interface, and analyze the 
>> packets in question as UHD (some/many will be sample packets, i.e. 
>> CVITA).
>> Best regards,
>> Marcus
>> On 24.05.2017 20:15, ROBIN TORTORA via USRP-users wrote:
>>> The only thing that jumps out to me is they are all on the same 
>>> subnet...
>>> That is something I have typically avoided, but if you say it works 
>>> in another configuration, that may not be the issue...
>>>> On May 24, 2017 at 12:12 PM Kevin Krieger via USRP-users 
>>>> <usrp-users at lists.ettus.com> wrote:
>>>> Hi all,
>>>> I've got a predicament. Here's some *background* before I describe 
>>>> my problem:
>>>> We purchased a Netgear xs728T 10GB switch in order to network 16 
>>>> N200 devices, as well as a processing computer (which has a 10G 
>>>> ethernet card). Our 16 N200 devices are going to be used in a radar 
>>>> configuration where they are all simultaneously either transmitting 
>>>> or receiving. They are all receiving coincident 10MHz and 1PPS 
>>>> signals from 2 octoclocks, which are both fed from a third clock to 
>>>> ensure coincident clocks. They are connected to the switch via cat6 
>>>> cables ~7feet in length (this item: 
>>>> https://www.newegg.ca/Product/Product.aspx?Item=N82E16812119168&_ga=2.227605844.817843194.1495640587-1295759170.1493911136)
>>>> *The problem:*
>>>> During testing we've found that the example program tx_bursts, when 
>>>> run on one USRP at a time with a modest bandwidth, the "Waiting for 
>>>> async burst ack....failed" message appears about 75% of the time. 
>>>> If I try to use two or more USRPs at a time, then it appears every 
>>>> time.
>>>> The line used for tx_bursts was typically something like 
>>>> this:./tx_bursts --args="addr0=" --freq 10e6 
>>>> --rate=1e6 --channels="0"
>>>> for a one usrp test. For a multiple usrp test, I used lines like 
>>>> this:./tx_bursts 
>>>> --args="addr0=,addr1=,addr2=,addr3=,addr4=,addr5=,addr6=" 
>>>> --freq 10e6 --rate=1e6 --channels="0,1,2,3,4,5,6"
>>>> *Some evidence & information:
>>>> *We also have a 5 port 1G DLink DGS-1005G. We've tested 4 N200s 
>>>> with tx_bursts on this switch (same cabling) and it works flawlessly.
>>>> We also have tested a second 10G switch, the 8 port XS708E with 7 
>>>> N200s with tx_bursts and it works flawlessly.
>>>> I have wireshark dumps taken via a third machine that is connected 
>>>> to mirrored ports on the xs728T switch. I have attached them in 
>>>> case anyone can tell me if they see something wrong besides the 
>>>> missing acks.
>>>> The wireshark filter to use is : ip.src == and 
>>>> ip.dst == or ip.src == and ip.dst == 
>>>> The xs728t switch information is: Boot version is, SW 
>>>> version is (latest as of testing).
>>>> I contacted Netgear support, and they sent us a brand new switch, 
>>>> which exhibited the same problem.
>>>> I'm wondering if there's anyone out there who has had similar 
>>>> issues? Is there anything I can do to get more information or get 
>>>> around this problem?
>>>> Can anyone see what the root cause might be in the wireshark captures?
>>>> Any help or pointers are appreciated. Thank you,
>>>> Kevin
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