Re: [Discuss-gnuradio] Ettus Research Announcements -- Nov 2010

[Marcus D. Leech]

On 11/16/2010 08:20 PM, Steve Mcmahon wrote:
> Secondly, what is performance penalty of UHD interface versus the raw Ethernet 
> interface? UHD is based on UDP, so certainly there must be some reduction in 
> the maximum data rate (and thus the bandwidth) compared the raw Ethernet 
> interface. UDP certainly adds overhead...
With UHD, you can manipulate the maximum frame sizes to an extent that 
the extra bytes in the header disappear "into the noise", so one
  (IMHO) shouldn't be concerned that UHD is a "lesser" beast in terms 
of on-the-wire performance.

I run a Rx-only UHD USRP2+DBS_RX in my lab 
(http://science-radio-labs.com) at 25Msps, and it's fine.  I don't think 
that the packet
  overhead is really that big an issue.

> Finally, if the USRP N210 only supports the new UHD interface, what is the 
> reason that the current raw Ethernet interface is being deprecated in favor of 
> UHD? What are the advantages of UHD compared to raw Ethernet? What are the 
> disadvantages?
****************************** STRICTLY WEARING MY USRP1/USRP2 
USER/CUSTOMER HAT HERE **************************************
From my point of view, as a *user* of Ettus hardware with Gnu Radio, 
UHD provides a more uniform abstraction layer for various physical
  devices that fit in the Analog-goop+{ADC,DAC}+FPGA+data-pump 
category.  It's nice not having your application need to "know"
  too much about the devices it'll be connected to.  Prior to UHD, 
there was no convenient way to do that (not that there was *no* way,
  just no *convenient* way).  Plus UHD is more platform-neutral than 
what went before.  It will allow Ettus (and anyone else who licenses
  UHD technology, I guess) devices to be used in a broader "eco-system" 
of SDR technology, and that's never a bad thing.