[Discuss-gnuradio] Gigabit ethernet

[David Carr]

Hi all,

Has anyone looked into using gigabit ethernet is an interface to 
software radio hardware?

There are some definite benefits:
-max data rate ~750Mb/s, the rest is lost as signaling overhead
-can do nifty tricks like multi-casting to multiple hosts or sending 
different streams to different hosts.  One could then throw multiple 
machines at high-bandwidth problems
-gigabit ethernet interfaces are becoming common and cheap
-hardware is not that expensive (PHY ~$15)
-can remotely locate hardware

Downsides
-have to implement PCI or gigabit MAC in FPGA
-not trivial to implement (either of above)
-latency (could be mitigated to < 1ms -- comparable to USB)

It seems like to best approach to this would be to use an external PHY 
and implement the MAC in the FPGA.  The PHY would use the GMII or RGMII 
interfaces.  Implementing the MAC is difficult but doable and there 
exist things like the 10/100 opencores MAC to use as a guide.  How much 
network stack would we need?  I think that we'd use the jumbo frame size 
and UDP.

Just an idea,
-David Carr