On Wed, Mar 04, 2015 at 08:52:34AM +0100, Mark Kettenis wrote: > > * How much work is required? Is the work required in the order of days, > > weeks, months? > > Depends. 11n station support is probably something of the order of > days to a couple of -weeks. AP support is likely to be significantly > more work.
The actual amount of work depends on when you consider support complete. 11n has such a large feature set and optional parts that you can't simply say "this is an 11n device" to explain what your device can do. Are you done when one driver supports 11n? When all drivers capable of 11n support it? Out of the 77 modulation and coding schemes, which ones do you want? For stations the minimum is 8 out of those, which leaves you with a maximum 72Mbit/s (single-channel at 2Ghz). APs need at least 16 of them (maximum 144Mbit/s). Do you want 150Mbit/s (single antenna maximum)? Or do you require MIMO (multiple antennas), with a maximum of 300Mbit/s with 2 antennas? 450 Mbit/s with 3 antennas? 600Mbit/s with 4 antennas? > > * Would parts of FreeBSD's implementation be useful, or are the two > > network stacks different enough that a new implementation is > > required? > > The OpenBSD 802.11 stack already has 11n bits in it. They have not > really been tested though, so more fixes will be necessay. I don't > think the FreeBSD code is going to help much. > > I expect most of the work to be in driver code. Based on code and literature I've read so far, I would agree here. > > I'm a relatively competent C programmer, but I have very little > > experience with kernel code, much less network protocols. I would > > like to use OpenBSD as an access point, but I need wireless-n @ 5GHz in > > order to do so, so I'm motivated enough to allocate some time for > > testing and even writing code. I could probably also supply some basic > > hardware if that would help, though I don't have a big budget. > > I don't want to discourage you, but AP support for 11n will be quite > an effort. Even if somebody gets 11n to work, I think it will be hard > work to make it work well. Some people here will claim that OpenBSD > 11a/11g APs don't really work very well. My 11a athn(4) AP is working quite well. Apart from the fact that the soekris hardware won't really keep up when I pump data from cable to antenna at 54Mbit/s. 11n support would definitely require slightly more modern hardware ;-)
