Hi Martin, On Sat, 19 Feb 2011, Martin Birgmeier wrote:
MB>p.s. A few :-) of the questions I have are MB> MB>- why the original (as I understand HARP) ATM stack was removed (in the CVS MB>logs the reason cited is the usual giant lock issue of that time), This is one reason. Another problem was, that HARP was a rather umaintainable monolithic block of code. Many years ago I needed to do modifications in the ATM signaling and that was just impossible. So I decided to build all the stuff on NATM which rather nicely fits into the socket framework. MB>- what the differences between the atm and natm stacks are (as I understand MB>the latter only supports a subset of the functionality of the former - only MB>AAL5?), NATM is a very thin layer to be able to use VCIs directly in an application. All the stuff in ng_atm can be used together with NATM and provides a modular framework for doing ATM work. There are missing pieces like CLIP and a decent connection of the ATM signaling to the socket interface, but my interest in this dropped because ATM is basically given up by industry. Except for the use in ADSL (which is slowly phased out by the new DSL standards) it is dead. MB>- why AF_NATM is different from AF_ATM (hinting that NATM is not a MB>replacement of ATM), AF_NATM allows you to bind VCIs with AAL5 or AAL0 (raw cells). AF_ATM had also an ad-hoc interface to signaling. MB>- whether and how it is even possible to inject raw ATM cells, AF_NATM with AAL0. MB>- whether I even need "options NATM" (currently I can happily instantiate a MB>(of course non-functional) ATM interface using just "device atm"), Since time has passed I'm not sure on this. You need optiosn NATM either to do IP over ATM directly or to get the AF_NATM stuff. Don't remember, sorry. MB>- what do I need to do on the USB side to start receive and transmit machines MB>(do I need to start separate kernel threads or just issue two MB>usbd_transfer_setup() calls as for loading the firmware), I'v no idea on this. I would suppose, that your driver would appear to the atm stack as an ATM interface, right? MB>I do of course read the source, but with the scarce documentation available MB>that's a steep learning curve. You may try to look up the original paper on NATM - its a nice reading as far as I remember... harti _______________________________________________ email@example.com mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-usb To unsubscribe, send any mail to "freebsd-usb-unsubscr...@freebsd.org"