On Tue, 28 Jan 2014 00:52:26 +0400 Dmitry Eremin-Solenikov <dbarysh...@gmail.com> wrote: > I have a question regarding LBT. Isn't it just another clear channel > assessment mode? Not from the terms in the standard maybe, but from > the logical point of view. Another type would be ALOHA (IIRC), maybe > some other types. What about adding single generic interface that > will select between those channel availability check methods? Thus > you would merge together patches #4 and #5 and replace them with a > single generic API (I'm not so sure about patch #6 - set_cca_ed).
No, it's an alternative to CSMA. Usually, you will use CSMA with exponential backoffs to determine whether the channel is free for you to use, or wait until it is. LBT replaces this with a predetermined (long) wait before you may send at all, and more (long) waits between transmission attempts. Both CSMA and LBT use CCA to determine whether the channel is free or not though, so i don't think it's i a good idea to merge the two features into one. > Patch #7 is another topic. It is about MAC acceleration features. The > problem is that this (potentially) clashes with > multiple-interface-per-mac support. I will think later how to fit that > in, ok? Actually, it is a bit more, on RF2xy at least. First some things I found while digging a bit deeper in the linux stack: * dgram sockets have sockopts to send packets with the REQ_ACK flag * 6lowpan sends all packets except broadcasts with that flag It makes sense to send ACKs to a sender that requests them, which is what the RX_AACK modes usually do. In RF2xy, this mode also has some other features, but the driver disables or ignores them, so we might as well switch to RX_AACK by default. Further, TX_ARET modes in RF2xy enable CSMA (and LBT), automatic handling of ACKs, failure after a number of retries and such things. We might use TX_ARET if a xmit skb has the REQ_ACK flag set, but to use CSMA/LBT (which we must, to stay withing regulations), we must use TX_ARET in RF2xy either way. I propose to drop patch #7 entirely and use RX_AACK and TX_ARET modes by default in RF2xy for exactly this reason. ------------------------------------------------------------------------------ WatchGuard Dimension instantly turns raw network data into actionable security intelligence. It gives you real-time visual feedback on key security issues and trends. Skip the complicated setup - simply import a virtual appliance and go from zero to informed in seconds. http://pubads.g.doubleclick.net/gampad/clk?id=123612991&iu=/4140/ostg.clktrk _______________________________________________ Linux-zigbee-devel mailing list Linux-zigbee-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-zigbee-devel
