path: root/Documentation/ABI/testing/sysfs-class-net-mesh
diff options
authorMartin Hundebøll <martin@hundeboll.net>2013-01-25 11:12:38 +0100
committerAntonio Quartulli <ordex@autistici.org>2013-03-13 22:53:48 +0100
commitd353d8d4d9f0184ac43a90c6e04b593c33bd28ea (patch)
treeb38d3477b0daab818b41fbb36664d1f8c0789801 /Documentation/ABI/testing/sysfs-class-net-mesh
parentbatman-adv: don't use !! in bool conversion (diff)
batman-adv: network coding - add the initial infrastructure code
Network coding exploits the 802.11 shared medium to allow multiple packets to be sent in a single transmission. In brief, a relay can XOR two packets, and send the coded packet to two destinations. The receivers can decode one of the original packets by XOR'ing the coded packet with the other original packet. This will lead to increased throughput in topologies where two packets cross one relay. In a simple topology with three nodes, it takes four transmissions without network coding to get one packet from Node A to Node B and one from Node B to Node A: 1. Node A ---- p1 ---> Node R Node B 2. Node A Node R <--- p2 ---- Node B 3. Node A <--- p2 ---- Node R Node B 4. Node A Node R ---- p1 ---> Node B With network coding, the relay only needs one transmission, which saves us one slot of valuable airtime: 1. Node A ---- p1 ---> Node R Node B 2. Node A Node R <--- p2 ---- Node B 3. Node A <- p1 x p2 - Node R - p1 x p2 -> Node B The same principle holds for a topology including five nodes. Here the packets from Node A and Node B are overheard by Node C and Node D, respectively. This allows Node R to send a network coded packet to save one transmission: Node A Node B | \ / | | p1 p2 | | \ / | p1 > Node R < p2 | | | / \ | | p1 x p2 p1 x p2 | v / \ v / \ Node C < > Node D More information is available on the open-mesh.org wiki[1]. This patch adds the initial code to support network coding in batman-adv. It sets up a worker thread to do house keeping and adds a sysfs file to enable/disable network coding. The feature is disabled by default, as it requires a wifi-driver with working promiscuous mode, and also because it adds a small delay at each hop. [1] http://www.open-mesh.org/projects/batman-adv/wiki/Catwoman Signed-off-by: Martin Hundebøll <martin@hundeboll.net> Signed-off-by: Marek Lindner <lindner_marek@yahoo.de> Signed-off-by: Antonio Quartulli <ordex@autistici.org>
Diffstat (limited to 'Documentation/ABI/testing/sysfs-class-net-mesh')
1 files changed, 8 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-class-net-mesh b/Documentation/ABI/testing/sysfs-class-net-mesh
index bc41da61608d..bdcd8b4e38f2 100644
--- a/Documentation/ABI/testing/sysfs-class-net-mesh
+++ b/Documentation/ABI/testing/sysfs-class-net-mesh
@@ -67,6 +67,14 @@ Description:
Defines the penalty which will be applied to an
originator message's tq-field on every hop.
+What: /sys/class/net/<mesh_iface>/mesh/network_coding
+Date: Nov 2012
+Contact: Martin Hundeboll <martin@hundeboll.net>
+ Controls whether Network Coding (using some magic
+ to send fewer wifi packets but still the same
+ content) is enabled or not.
What: /sys/class/net/<mesh_iface>/mesh/orig_interval
Date: May 2010
Contact: Marek Lindner <lindner_marek@yahoo.de>