On Fri, Mar 16, 2007 at 01:27:38PM +0100, Stefan Sperling wrote: > Hello, > > I've recently got a ral-based card and I have a problem in IBSS mode. > It seems that ral fails to send any kind of packets larger than > 200 bytes (192 bytes + 8 bytes icmp header).
Just for the record, I've found the problem. First, I was able to reproduce it with an atw(4) card. This made me take a look at the other end of the connection. The ibss station I was trying to connect to is a WRT54G running a modified version of openWRT (not BSD). The wifi driver it's using is the proprietary wl driver for Broadcom chips in Linux 2.4 (yuck, I know). The driver has a fragmentation setting (this has apparently nothing to do with MTU). It was set to 256 (presumably bytes). Since I've told the driver not to do fragmentation openbsd connects to the node just fine with ral(4). No more truncated packets reported by tcpdump :-) The connection seems to be very stable so far. I'm happy. Does anyone know more about this fragmentation thingy? Could it be some broadcom-specific non-standard "feature" that no-one else supports? Or is it something that some drivers in OpenBSD simply lack support for? As mentioned in my original report wi(4) seemed to be able to cope. atw(4) seems to have other issues, it sometimes seems to simply loose the ability to send packets in ibss mode. All of a sudden pings get cut off. Locally, tcpdump still sees them going out on atw0 but they never reach the other station. I can reliably reproduce this, but I won't bother sending a bug report since I can use my ral card now, so I'm fine. I can provide details on request if someone seriously wants to fix atw(4). -- stefan http://stsp.in-berlin.de PGP Key: 0xF59D25F0
