[USRP-users] B210 over Network?

Marcus Müller marcus.mueller at ettus.com
Mon Apr 20 09:08:30 EDT 2015

Hi Raj,

On 04/20/2015 02:49 PM, Raj Bhattacharjea via USRP-users wrote:
> I've thought of recording the network traffic to/from an N-series
> using wireshark and looking into the N-series UHD source code / FPGA
> code to try to figure out the protocol and make my own implementation
> for some of the functionality for the B series. If I ever get this
> idea off the ground and post a git repo, I'll send it out to this list.
No need to dig/reverse engineer, the sample packets are simply VITA-49.
There's a dissector for that in wireshark, and there's a dissector for
the UHD control protocol, too.

The N210's control protocol is very simple, and is based around the host
asking and instructing the USRP on a low level to talk to the
daughterboard, set up DSP chains etc. I'd recommend having a look at the
uhd/host/lib/usrp/usrp2/usrp2_impl.cpp and usrp/cores/*200.cpp and
comparing that to usrp/b200/b200_impl.cpp.

The b200 architecture is not really closely similar to the usrp2/n200
architecture; you can't just change a few things in usrp2_impl and
transparently move to ethernet, I'm afraid.

In essence: Due to overhead and latency, encapsulating the raw USB
packets (which there are implementations of) is not an option;
everything higher-level sounds a bit application-specific, so there
wasn't much need to do a network server for that on the B2x0.
In fact, for the E310, we have such a diagnostic network mode, but there
the samples are moved from the FPGA into the CPU's cache, and handling
is a bit closer to the metal than for external busses, and throughput is
really not considerable for application purposes, though things are
heavily optimized.
To put it a bit nicer: The N2x0 is designed and strongly optimized to be
a network device, the B2x0 a USB3 device -- since this puts some
constraints on how things have to be done, there's no easy "universal"
way to put one's control and data flow through the other's transport.

Best regards,

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