Dear Rob, Thanks for your helpful response. The reason that we need to use a switch is due to hour host hardware limits, which only have one 10GBE. About the second remark in your email, do you have an example or a reference where a similar case was implemented which we can use as a guideline for our implementation?
Best regards, Farnaz On Thu, Jul 26, 2018 at 7:52 PM, Rob Kossler <rkoss...@nd.edu> wrote: > Hi Farnaz, > A couple of remarks and questions > - Remark 1: in order to get 200 MS/s transmit streaming, you will NEED to > have the samples on the USRP. The host-to-USRP streaming does not work at > 200 MS/s for the transmit case (unless something has recently changed). The > host-to-USRP max for transmit is 100 MS/s per channel > - Remark 2: that leads into your question about having the samples stored > on the USRP rather than streamed from host. This is not presently a > capability, but can be added with some modest FPGA work. I have been > desiring such capability for a couple of years - I hope that Ettus adds > such capability in the future. > - Question 1: why do you plan to use a 10gbe switch with a single > connection to the host PC? Why not have multiple 10Gbe links at the PC > which connect to each USRP individually. A NIC such as Intel XL-710 > provides 4 10gbe links. > > Rob > > > On Thu, Jul 26, 2018 at 12:13 PM Farnaz Chamanzadeh via USRP-users < > usrp-users@lists.ettus.com> wrote: > >> Dears, >> >> To be more specific, we want to control multiple USRPs with one (remote) >> computer. We would like to stream known and periodic signal from each USRP. >> The sequence on each USRP is unique and is different from other USRPs. >> >> Since the samples from each USRP are known, it would be more >> convenient if we can generate the samples once and preferably store them >> locally on each USRP. In this configuration, we want to use the host >> computer to send control commands to the USRPs specifying when each of them >> must transmit its specific samples. The USRPs are assumed to be >> synchronized, so the control commands from the host will generate a TDMA >> scheme. Each USRP will start signal transmission upon receiving the control >> command from the host computer. I would like to know that: >> >> 1. Is it possible to store the samples on the USRPs? or should we stream >> the samples from the host computer to the USRPs for each transmission? >> 2. Can we use the full bandwidth and 200MS/s in this setup? >> 3. After knowing the answer to the previous question, I would like to >> know how we can implement it? do you happen to have a demo or an example >> that can guide us in this implementation? >> >> Best, >> Farnaz >> >> >> >> >> >> >> On Wed, Jun 27, 2018 at 4:50 AM, Michael West <michael.w...@ettus.com> >> wrote: >> >>> Hi Farnaz, >>> >>> To clarify and expand on Marcus' comments, the answer is maybe. You can >>> do burst captures and transmissions at full rate and you can even use timed >>> commands to synchronize them, but there are limitations. If you can >>> describe in more detail what you want to do, we can more clearly tell you >>> if it is possible. How many channels do you plan to do simultaneously? >>> How many 10 GbE connections between the host and switch? How many 10 GbE >>> connections between each USRP and the switch? >>> >>> There is buffering of the TX samples on the X310 and it is >>> configurable. The current default is 32 MB. The DRAM is a total of 1 GB, >>> and it can be divided up however necessary. >>> >>> Regards, >>> Michael >>> >>> On Mon, Jun 25, 2018 at 12:23 PM, Marcus Müller via USRP-users < >>> usrp-users@lists.ettus.com> wrote: >>> >>>> Dear Fernaz, >>>> >>>> you can't cheat 10Gig bandwidth! If you time-share any medium, then >>>> it's bandwidth must be shared. Since ethernet is de facto a timesharing >>>> thing, anyway, no, this won't work: >>>> Since you need to push through all the data through a single 10GigE >>>> connection, your 10 gigabits per second need to be divided along *all >>>> simultaneously operating* USRPs. So, if you have, say 10 USRPs, and all >>>> should be working at the same time, you've only got 1 gigabit per >>>> second per USRP, which limits you to about 25 MSample/s per USRP. It's >>>> really the same principle as a single internet access being shared by >>>> all people attached to the same router. >>>> >>>> Now, if these USRPs *don't* have to transmit all at the same time, then >>>> more is possible. >>>> >>>> > Also, does anyone know if it is possible to store the samples on the >>>> transmit USRPs? >>>> >>>> I'll go with a: no, at least probably not like you hope it is. Can you >>>> elaborate on your use case? Maybe we can help you if we better >>>> understand what you're trying to implement, from a bit of distance? >>>> >>>> Best regards, >>>> Marcus >>>> >>>> On Mon, 2018-06-25 at 20:32 +0200, Farnaz Chamanzadeh via USRP-users >>>> wrote: >>>> > Dear all, >>>> > >>>> > I want to connect multiple USRP X310 to one host PC and control them >>>> > all from that Pc, using one 10Gigabit Ethernet switch. My question >>>> > is that if it is possible to stream from each USRP in a different >>>> > time slot using the full bandwidth and 200MS/s in a setup similar to >>>> > the picture below? >>>> > >>>> > Also, does anyone know if it is possible to store the samples on the >>>> > transmit USRPs? >>>> > >>>> > >>>> > >>>> > >>>> > Best, >>>> > Farnaz >>>> > >>>> > _______________________________________________ >>>> > USRP-users mailing list >>>> > USRP-users@lists.ettus.com >>>> > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >>>> >>>> _______________________________________________ >>>> USRP-users mailing list >>>> USRP-users@lists.ettus.com >>>> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >>>> >>> >>> >> _______________________________________________ >> USRP-users mailing list >> USRP-users@lists.ettus.com >> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >> >
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