Dennis Windisch wrote: >> The standard start script is not prepared to handle the "TDMA-less" >> scenario. Please have a look at the rough description I recently added >> to the main README (see SVN repository) about starting manually. > > Thanks, now I can start rteth0.
Fine, another happy user today. :) > > But I'm a little confused about RTnet and RTmac/TDMA. When I use RTnet > without RTmac (which uses TDMA), what will I be "losing"? I mean, what > functions or features won't work? > Since I would like to set up a RT-network without RTmac/TDMA (which > according to the documentation is optional), what do I have to consider? > Have I to write a new RT-networking protocol which handels the > communication in my RT-network? Or in other words: What does RTnet > guarantees me (or handels for me) even without RTmac/TDMA (like the > possibility to do RT-networking)? > The RTnet core provides a deterministic networking stack with respect to o packet buffer management (pre-allocation, decoupling of users) o IP/UDP implementation (static ARP, IP defragmentation) o real-time Linux integration (of course) RTmac with some discipline (so far only TDMA, NoMAC is just a skeleton) can compensate indeterministic media access characteristics like Ethernet shows. It is not necessarily needed when you use special switching technology (with QoS support and hard timing guarantees) or pick deterministic transport services (e.g. isochronous transfer via FireWire - but that transfer type is not yet attached to RTnet via RT-FireWire). Additionally, TDMA offers a synchronised clock across all attached nodes (see API in stack/include/rtmac.h). Jan
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