From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <002b01c43680$a4ba19b0$0500a8c0@pii350> From: "Marc Fouquet" To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Subject: [Bluez-users] BlueZ Timing Resolution Sender: bluez-users-admin@lists.sourceforge.net Errors-To: bluez-users-admin@lists.sourceforge.net List-Unsubscribe: , List-Id: List-Post: List-Help: List-Subscribe: , List-Archive: Date: Mon, 10 May 2004 12:18:59 +0100 Hello! I am trying to do "Packet Pair" measurements with Bluetooth for an University Project. This means that I am sending two IP packets as quickly as possible at the sender and measure the difference between the arrival times of the packets at the receiver (with tcpdump for example). This inter-arrival time between two IP packets always appears to be a multiple of 1 ms when using BlueZ, for example: 0.026006 s between packet 0 and 1 0.041003 s between packet 2 and 3 0.025990 s between packet 4 and 5 0.029987 s between packet 6 and 7 0.029997 s between packet 8 and 8 0.030001 s between packet 10 and 11 With other networks - for example ethernet - I can measure inter-arrival times that are much shorter than 1 ms. I would need to know the exact reason for the limited timing resolution with Bluetooth. Does the BT hardware give packets to my Computer only once a ms? Or does the BlueZ module only give the packets to the kernel once a ms? Why 1 ms and not a multiple of the BT slot time of 625 microseconds? I am using Fedora Core 1 with Kernel 2.4.22, bluez-libs 2.5, bluez-utils 2.4 (the lastest versions that were available as rpms), a bnep (pand) connection, 2 MSI Bluetooth USB Sticks. Thanks and greetings from Germany Marc Fouquet ------------------------------------------------------- This SF.Net email is sponsored by Sleepycat Software Learn developer strategies Cisco, Motorola, Ericsson & Lucent use to deliver higher performing products faster, at low TCO. http://www.sleepycat.com/telcomwpreg.php?From=osdnemail3 _______________________________________________ Bluez-users mailing list Bluez-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bluez-users