Poor Data Rates with the USRP E312

Hi all,

I'm attempting to use the USRP E312 as a wifi node using the gr-ieee802.11 module...

though for now I'm testing basic USRP functionality with a couple of simple GNU graphs. 

Here's my setup:

- the host is an Ubuntu 18.04 virtual machine with a bridged adaptor. Firewall disabled.

- the USRP is the E312, connected via ethernet to the host network. 

- the host and USRP are both running GR3.8 and UHD4.0 (Zeus branch).

- the host can see the USRP with uhd_usrp_probe.

- the USRP is running the following GNU graph - UHD:USRP Source -> UDP Sink.

- host is running the following GNU graph - UDP Source -> QT GUI Sink.

- all block parameters are default.

I'm experiencing the following issues:

1. For sample rates > ~2Msps, the USRP spams overrun "O" and "D" characters (what does the "D" signify?) , regardless of whether the host graph is running or not.

2. At any sample rate the host graph spams the following message (when the USRP graph is running) - "gr::log :WARN: udp_source0 - Too much data; dropping packet."

And a question:

3. What sample rates are realistic for this setup, and what are the limitations? wifi channels span 20MHz, so I'm hoping to run at 20Msps

Thanks,

Joe