From mboxrd@z Thu Jan 1 00:00:00 1970 From: sandeep suresh Date: Sun, 27 Mar 2016 16:43:29 +0000 (UTC) Subject: [ath9k-devel] Bonjour mDNS broacast can be lost during BT-WLAN coexistence schemes? References: <1860079637.618245.1459097009016.JavaMail.yahoo.ref@mail.yahoo.com> Message-ID: <1860079637.618245.1459097009016.JavaMail.yahoo@mail.yahoo.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: ath9k-devel@lists.ath9k.org Dear Experts, WiFi-BT Coexistence: To let wireless LAN systems coexist with Bluetooth system, a hardware Packet Traffic Arbiter (PTA) scheme is used. Here PTA is based on 2-wire coexistence , BT_ACTIVE and WL_ACTIVE. When BT wants to use the medium, it will assert the BT_ACTIVE line, during which WLAN cannot perform any transactions. When WLAN is in client mode, during this assertion period waiting for a packet from WLAN router (AP) to be received , WLAN packet will be lost !!! Let us call this window during which WiFi being stomped ?by BT as stomping window. WLAN device in client mode considered here is based on AR9287 chipset and let us call this as Apple accessory? Bonjour discovery:Apple devices connect to the same WiFi router to which the Apple accessory is also connected. Apple device is also connected in WiFi client mode. ?In order to determine other clients (Apple compatible) in the same network, it performs Bonjour discovery which is based on mDNS broadcast. Concern/Query:-?The mDNS query is a broadcast query received from Apple device and sent by the WiFi AP to the WiFi network (to which the apple accessory is also connected) only once. The period of reception of this broadcast query can coincide with the stomping window. Hence the broadcast query can be lost by Apple accessory. This might result in discovery, pair verify (later) from apple devices to fail. Apple devices implement a back-off strategy and as per this the next discovery will be after 10s of minutes. During this long period the WiFi client based apple accessory will be offline!!!!? Is the understanding and concern correct? If so, how can this be solved via ath9k drivers and/or settings in WiFi AP? Regards Sandeep -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.ath9k.org/pipermail/ath9k-devel/attachments/20160327/eb6300be/attachment.htm