Re: [RTnet-developers] multicast support

[Amine El h. <am...@an...>]

think you Jan for this explanations.
Now im traying to build a mark of linux multicast working. So to port it to 
rtnet , i will need some informations about RTNET archetecture . that will 
help to do it cleanly and correctly.

Amine

On Tuesday 24 May 2005 20:58, you wrote:
> Amine El hedadi schrieb:
> > I need to use rtnet for audio & video streaming , so i want to add
> > support for multicasting to rtnet.
> > Now im trying to understand the working of mutlicasting in linux kernel,
> > and i look for the way to port it to rtnet.
> > So if you have any propositon to do that , please let me know.
>
> Beyond the aspect of how to manage rtskbs (RTnet's real-time packet
> buffers) for which I already posted a mail thread link, you should
> certainly first start with multicast at Ethernet level. First, you need
> support in at least one driver. Pick one and extend (or re-enable) its
> multicast features. Watch out for potentially required hard real-time
> synchronisation means between transmission/reception handlers and
> multicast manipulation functions. Feel free to ask what to use or how
> certain things work inside the driver.
>
> Next, it's likely useful to add the required API to the packet socket
> interface (stack/packet/af_packet.c). That API has to provide means for
> registering to and detaching from a multicast group at Ethernet protocol
> level. Check Linux man pages etc. for documentation.
>
> Later, the integration in RTnet's UDP/IP stack can be addressed. Here,
> the question needs to be answered how to map the multicast IP address on
> Ethernet MAC addresses. Not sure right now how this happens in normal
> networks, but I guess a static configuration is likely the easiest way
> for a first approach in RTnet.
>
> Looking forward to further discussions! I'm also interested in learning
> more about multicast implemenation and potential hard real-time issues.
>
> Jan