Re: Remarks concerning IP-over-DVB

[Patrick Cipiere <Patrick.Cipiere@udcast.com>]

Patrick Cipiere wrote:

>> I am also using cards that do not hardware filter the PIDs, but leave
>> this task to the driver. With these  cards it is easier to deal with the
>> whole 8191 PIDs, but cost more cpu cycles.
>> 

Gorry wrote:

> Yes - I also presume this offers a way to modify the IP protocol
> processing with some existing cards. How much experience do you
> have of this?

Emmanuel Duros <Emmanuel.Duros@UDcast.com> and I already wrote 6
drivers for different DVB-S cards and manufacturers running with
FreeBSD. And we are currently coding a new one.
We try to make them as simple as usual ethernet drivers.
In fact we consider the driver as an ethernet layer 2 driver, and we
consider that RF/mpeg2/mpe are in layer 1.
By doing so, the DVB-S NIC card/driver fits nicely in the stack, with
standard ethernet interface with layer 3.

This might explain my previous remark about layering.

I strongly believe that we need a source MAC address, and this can be
solved today with LLC_SNAP and RFC1483.
This need is reinforced when using RFC3077 on this interface, because
you transform a unidirectional simplex interface into a duplex
interface.
The interface needs to be able to reject its own packets (received
250ms later).

Patrick.
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