Return-Path: Subject: Re: [Bluez-users] ISSC USB dongle can't ping with size 1000 From: Marcel Holtmann To: bluez-users@lists.sourceforge.net In-Reply-To: <1140692268.24721.22.camel@localhost> References: <1140692268.24721.22.camel@localhost> Content-Type: text/plain Message-Id: <1140693818.24721.29.camel@localhost> Mime-Version: 1.0 Sender: bluez-users-admin@lists.sourceforge.net Errors-To: bluez-users-admin@lists.sourceforge.net Reply-To: bluez-users@lists.sourceforge.net List-Unsubscribe: , List-Id: BlueZ users List-Post: List-Help: List-Subscribe: , List-Archive: Date: Thu, 23 Feb 2006 12:23:38 +0100 Hi Al, > > I have the same problem as below which was posted last month. > > > > > I started to play with the ping size. 'ping -s 900' works, 'ping -s 1000' > > > kills the PAN connection. There was hope! Then I played with MTU (on both > > > sides): 'ifconfig bnep0 mtu 1000' solves all my problems (default is > > > 1500)!!! With this setting I've a rock solid 75 kByte/s transfer rate over > > > ftp. A mtu of 1017 still works, 1018 definitely kills the connection. > > > > I wonder if there is other solutions to this problem cause the above solution needs to set MTU to 1000 on both sides. > > > > I try ISSC dongle with IVT software as NAP on Windows XP. Ping with size > > 1500 works fine. It seems ISSC chip has some problems to work with BlueZ, in > > addition to adding HCI_RESET. > > I am pretty sure that your chip is at fault here. I have no internals > about your chip, but whatever buffer size you tell us, we will use. And > BlueZ will use it as fast as possible. The latency is very low and the > HCI flow control works fine. So I assume there exists a race condition > in your side of the HCI flow control implementation which triggers a > problem. You can verify with hcidump that we do everything right. The > faulty application is actually not BNEP here. I think you can reproduce > it with any program sending big L2CAP packets. So a test setup with > l2test and different MTU might trigger it more easily. and I just did a quick search through the mailing list archive and actually I found these four version: ACL MTU: 678:12 SCO MTU: 48:5 LMP Ver: 1.1 LMP Subver: 0x172 ACL MTU: 678:8 SCO MTU: 48:5 LMP Ver: 1.1 LMP Subver: 0x1a4 ACL MTU: 678:8 SCO MTU: 48:10 LMP Ver: 1.2 LMP Subver: 0x1ae ACL MTU: 678:8 SCO MTU: 48:10 LMP Ver: 1.2 LMP Subver: 0x1f4 The LMP Subver must somehow decode into the version number of your firmware, but I have no idea how. However you see the different ACL MTU sizes the chip offers and BlueZ is simply using them. Regards Marcel ------------------------------------------------------- This SF.Net email is sponsored by xPML, a groundbreaking scripting language that extends applications into web and mobile media. Attend the live webcast and join the prime developer group breaking into this new coding territory! http://sel.as-us.falkag.net/sel?cmd=lnk&kid=110944&bid=241720&dat=121642 _______________________________________________ Bluez-users mailing list Bluez-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bluez-users