Return-Path: From: Marcel Holtmann To: BlueZ users In-Reply-To: References: Date: Sun, 03 Dec 2006 14:31:07 +0100 Message-Id: <1165152667.19590.5.camel@localhost> Mime-Version: 1.0 Subject: Re: [Bluez-users] data fragment Reply-To: BlueZ users List-Id: BlueZ users List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Sender: bluez-users-bounces@lists.sourceforge.net Errors-To: bluez-users-bounces@lists.sourceforge.net Hi Uichin, > I have an urgent question. I'm sending a 2300B packet from one machine > to another machine through L2CAP. I used hcidump to see the > fragmentation in L2CAP. > > I looked at the kernel code, and realized that L2CAP uses "ACL_MTU" to > do the fragmentation. hcidump at the sender side shows that > > < ACL data: handle 1 flags 0x01 dlen: 120 > > However, hcidump at the receiver side shows like this: > > > ACL data: handle 42 flags 0x01 dlen: 224 > => 10 times + > > ACL data: handle 42 flags 0x01 dlen: 64 > > Total 2304 (2300B payload + 4 bytes - CID/Length) > > What's happening here? At the lower layer (i.e., LMP), pack those > packets and then create another ACL packet with length 224 (the size > of DM5 packet). It seems like LMP packs uppper level data packets > into current baseband packet format. Is that true? I can't give you a clear answer to that. This depends on how the firmware on the Bluetooth chip implements the HCI. Sometimes HCI and LMP packet size match, but that is not a must. Regards Marcel ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Bluez-users mailing list Bluez-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bluez-users