Documentation/networking/batman-adv.txt

   1 [state: 21-11-2010]
   2
   3 BATMAN-ADV
   4 ----------
   5
   6 Batman  advanced  is  a new approach to wireless networking which
   7 does no longer operate on the IP basis. Unlike the batman daemon,
   8 which  exchanges  information  using UDP packets and sets routing
   9 tables, batman-advanced operates on ISO/OSI Layer 2 only and uses
  10 and  routes  (or  better: bridges) Ethernet Frames. It emulates a
  11 virtual network switch of all nodes participating.  Therefore all
  12 nodes  appear  to be link local, thus all higher operating proto-
  13 cols won't be affected by any changes within the network. You can
  14 run almost any protocol above batman advanced, prominent examples
  15 are: IPv4, IPv6, DHCP, IPX.
  16
  17 Batman advanced was implemented as a Linux kernel driver  to  re-
  18 duce the overhead to a minimum. It does not depend on any (other)
  19 network driver, and can be used on wifi as well as ethernet  lan,
  20 vpn,  etc ... (anything with ethernet-style layer 2).
  21
  22 CONFIGURATION
  23 -------------
  24
  25 Load the batman-adv module into your kernel:
  26
  27 # insmod batman-adv.ko
  28
  29 The  module  is now waiting for activation. You must add some in-
  30 terfaces on which batman can operate. After  loading  the  module
  31 batman  advanced  will scan your systems interfaces to search for
  32 compatible interfaces. Once found, it will create  subfolders  in
  33 the /sys directories of each supported interface, e.g.
  34
  35 # ls /sys/class/net/eth0/batman_adv/
  36 # iface_status  mesh_iface
  37
  38 If an interface does not have the "batman_adv" subfolder it prob-
  39 ably is not supported. Not supported  interfaces  are:  loopback,
  40 non-ethernet and batman's own interfaces.
  41
  42 Note:  After the module was loaded it will continuously watch for
  43 new interfaces to verify the compatibility. There is no  need  to
  44 reload the module if you plug your USB wifi adapter into your ma-
  45 chine after batman advanced was initially loaded.
  46
  47 To activate a  given  interface  simply  write  "bat0"  into  its
  48 "mesh_iface" file inside the batman_adv subfolder:
  49
  50 # echo bat0 > /sys/class/net/eth0/batman_adv/mesh_iface
  51
  52 Repeat  this step for all interfaces you wish to add.  Now batman
  53 starts using/broadcasting on this/these interface(s).
  54
  55 By reading the "iface_status" file you can check its status:
  56
  57 # cat /sys/class/net/eth0/batman_adv/iface_status
  58 # active
  59
  60 To deactivate an interface you have  to  write  "none"  into  its
  61 "mesh_iface" file:
  62
  63 # echo none > /sys/class/net/eth0/batman_adv/mesh_iface
  64
  65
  66 All  mesh  wide  settings  can be found in batman's own interface
  67 folder:
  68
  69 #  ls  /sys/class/net/bat0/mesh/
  70 #  aggregated_ogms  bonding  fragmentation  orig_interval
  71 #  vis_mode
  72
  73
  74 There is a special folder for debugging informations:
  75
  76 #  ls /sys/kernel/debug/batman_adv/bat0/
  77 #  originators  socket  transtable_global  transtable_local
  78 #  vis_data
  79
  80
  81 Some of the files contain all sort of status information  regard-
  82 ing  the  mesh  network.  For  example, you can view the table of
  83 originators (mesh participants) with:
  84
  85 # cat /sys/kernel/debug/batman_adv/bat0/originators
  86
  87 Other files allow to change batman's behaviour to better fit your
  88 requirements.  For instance, you can check the current originator
  89 interval (value in milliseconds which determines how often batman
  90 sends its broadcast packets):
  91
  92 # cat /sys/class/net/bat0/mesh/orig_interval
  93 # 1000
  94
  95 and also change its value:
  96
  97 # echo 3000 > /sys/class/net/bat0/mesh/orig_interval
  98
  99 In very mobile scenarios, you might want to adjust the originator
 100 interval to a lower value. This will make the mesh  more  respon-
 101 sive to topology changes, but will also increase the overhead.
 102
 103
 104 USAGE
 105 -----
 106
 107 To  make use of your newly created mesh, batman advanced provides
 108 a new interface "bat0" which you should use from this  point  on.
 109 All  interfaces  added  to  batman  advanced are not relevant any
 110 longer because batman handles them for you. Basically, one "hands
 111 over" the data by using the batman interface and batman will make
 112 sure it reaches its destination.
 113
 114 The "bat0" interface can be used like any  other  regular  inter-
 115 face.  It needs an IP address which can be either statically con-
 116 figured or dynamically (by using DHCP or similar services):
 117
 118 # NodeA: ifconfig bat0 192.168.0.1
 119 # NodeB: ifconfig bat0 192.168.0.2
 120 # NodeB: ping 192.168.0.1
 121
 122 Note:  In  order to avoid problems remove all IP addresses previ-
 123 ously assigned to interfaces now used by batman advanced, e.g.
 124
 125 # ifconfig eth0 0.0.0.0
 126
 127
 128 VISUALIZATION
 129 -------------
 130
 131 If you want topology visualization, at least one mesh  node  must
 132 be configured as VIS-server:
 133
 134 # echo "server" > /sys/class/net/bat0/mesh/vis_mode
 135
 136 Each  node  is  either configured as "server" or as "client" (de-
 137 fault: "client").  Clients send their topology data to the server
 138 next to them, and server synchronize with other servers. If there
 139 is no server configured (default) within the  mesh,  no  topology
 140 information   will  be  transmitted.  With  these  "synchronizing
 141 servers", there can be 1 or more vis servers sharing the same (or
 142 at least very similar) data.
 143
 144 When  configured  as  server,  you can get a topology snapshot of
 145 your mesh:
 146
 147 # cat /sys/kernel/debug/batman_adv/bat0/vis_data
 148
 149 This raw output is intended to be easily parsable and convertable
 150 with  other tools. Have a look at the batctl README if you want a
 151 vis output in dot or json format for instance and how those  out-
 152 puts could then be visualised in an image.
 153
 154 The raw format consists of comma separated values per entry where
 155 each entry is giving information about a  certain  source  inter-
 156 face.  Each  entry can/has to have the following values:
 157 -> "mac" - mac address of an originator's source interface
 158            (each line begins with it)
 159 -> "TQ mac  value"  -  src mac's link quality towards mac address
 160                        of a neighbor originator's interface which
 161                        is being used for routing
 162 -> "HNA mac" - HNA announced by source mac
 163 -> "PRIMARY" - this  is a primary interface
 164 -> "SEC mac" - secondary mac address of source
 165                (requires preceding PRIMARY)
 166
 167 The TQ value has a range from 4 to 255 with 255 being  the  best.
 168 The HNA entries are showing which hosts are connected to the mesh
 169 via bat0 or being bridged into the mesh network.  The PRIMARY/SEC
 170 values are only applied on primary interfaces
 171
 172
 173 LOGGING/DEBUGGING
 174 -----------------
 175
 176 All error messages, warnings and information messages are sent to
 177 the kernel log. Depending on your operating  system  distribution
 178 this  can  be read in one of a number of ways. Try using the com-
 179 mands: dmesg, logread, or looking in the files  /var/log/kern.log
 180 or  /var/log/syslog.  All  batman-adv  messages are prefixed with
 181 "batman-adv:" So to see just these messages try
 182
 183 # dmesg | grep batman-adv
 184
 185 When investigating problems with your mesh network  it  is  some-
 186 times  necessary  to see more detail debug messages. This must be
 187 enabled when compiling the batman-adv module. When building  bat-
 188 man-adv  as  part of kernel, use "make menuconfig" and enable the
 189 option "B.A.T.M.A.N. debugging".
 190
 191 Those additional  debug messages can be accessed  using a special
 192 file in debugfs
 193
 194 # cat /sys/kernel/debug/batman_adv/bat0/log
 195
 196 The additional debug output is by default disabled. It can be en-
 197 abled  during run time. Following log_levels are defined:
 198
 199 0 - All  debug  output  disabled
 200 1 - Enable messages related to routing / flooding / broadcasting
 201 2 - Enable route or hna added / changed / deleted
 202 3 - Enable all messages
 203
 204 The debug output can be changed at runtime  using  the  file
 205 /sys/class/net/bat0/mesh/log_level. e.g.
 206
 207 # echo 2 > /sys/class/net/bat0/mesh/log_level
 208
 209 will enable debug messages for when routes or HNAs change.
 210
 211
 212 BATCTL
 213 ------
 214
 215 As batman advanced operates on layer 2 all hosts participating in
 216 the  virtual switch are completely transparent for all  protocols
 217 above layer 2. Therefore the common diagnosis tools do  not  work
 218 as  expected.  To  overcome these problems batctl was created. At
 219 the  moment the  batctl contains ping,  traceroute,  tcpdump  and
 220 interfaces to the kernel module settings.
 221
 222 For more information, please see the manpage (man batctl).
 223
 224 batctl is available on http://www.open-mesh.org/
 225
 226
 227 CONTACT
 228 -------
 229
 230 Please send us comments, experiences, questions, anything :)
 231
 232 IRC:            #batman   on   irc.freenode.org
 233 Mailing-list:   b.a.t.m.a.n@b.a.t.m.a.n@lists.open-mesh.org
 234                 (optional   subscription   at
 235                  https://lists.open-mesh.org/mm/listinfo/b.a.t.m.a.n)
 236
 237 You can also contact the Authors:
 238
 239 Marek  Lindner  <lindner_marek@yahoo.de>
 240 Simon  Wunderlich  <siwu@hrz.tu-chemnitz.de>