[hpsdr] Call for Comments and Discussion - OzyII

[jeff millar]

Larry Gadallah wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
> 2009/7/19 Matthew J Wolf <mwolf at speciosus.net>:
>   
>> In the case of Ethernet Layer 2 (Data Link Layer) there are two IEEE
>> sublayers. First on the bottom is the IEEE 802.3 Access Control (MAC).
>> Then on the top of MAC is the IEEE 802.2 Logical Link Control (LLC),
>> http://en.wikipedia.org/wiki/Logical_Link_Control .
>>     
>
> Digging down a little further, it would be interesting to consider
> what EtherType (http://en.wikipedia.org/wiki/EtherType) would be most
> appropriate for use for OzyII (and/or other SDR applications). My
> thought is that we should try to select an existing EtherType with the
> most compatibility with current and future Ethernet switching/bridging
> devices as opposed to selecting our own or using some existing but
> obscure EtherType value that is either incompatible or not well tested
> with a broad range of Ethernet hardware. It might also be worth
> considering using an IEEE 802.2 header instead of an EtherType, since
> it would allow some rudimentary broadcast and routing capabilities.
>   
Regular Ethernet layer 2, when used with an Ethernet switch provides 
some routing capability. The switch learns which ports to connect based 
on which ports respond to traffic. Other ports don't get the majority of 
the traffic
> How about something like EtherType 0x8906 (Fibre Channel over
> Ethernet), since what we want to do basically is to ship a lot of data
> from an ADC and/or FPGA decimator to another host?
>   
The basic idea of using only the lower layers is to minimize the amount 
of logic necessary in the FPGA. Ethernet layer 2 is probably sufficient, 
What does fiber channel offer that would make the extra complexity 
worthwhile?

jeff, wa1hco



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