Documentation/networking/batman-adv.txt

   1 [state: 27-01-2011]
   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  gw_bandwidth  hop_penalty
  71 #  bonding          gw_mode       orig_interval
  72 #  fragmentation    gw_sel_class  vis_mode
  73
  74
  75 There is a special folder for debugging informations:
  76
  77 #  ls /sys/kernel/debug/batman_adv/bat0/
  78 #  gateways     socket        transtable_global  vis_data
  79 #  originators  softif_neigh  transtable_local
  80
  81
  82 Some of the files contain all sort of status information  regard-
  83 ing  the  mesh  network.  For  example, you can view the table of
  84 originators (mesh participants) with:
  85
  86 # cat /sys/kernel/debug/batman_adv/bat0/originators
  87
  88 Other files allow to change batman's behaviour to better fit your
  89 requirements.  For instance, you can check the current originator
  90 interval (value in milliseconds which determines how often batman
  91 sends its broadcast packets):
  92
  93 # cat /sys/class/net/bat0/mesh/orig_interval
  94 # 1000
  95
  96 and also change its value:
  97
  98 # echo 3000 > /sys/class/net/bat0/mesh/orig_interval
  99
 100 In very mobile scenarios, you might want to adjust the originator
 101 interval to a lower value. This will make the mesh  more  respon-
 102 sive to topology changes, but will also increase the overhead.
 103
 104
 105 USAGE
 106 -----
 107
 108 To  make use of your newly created mesh, batman advanced provides
 109 a new interface "bat0" which you should use from this  point  on.
 110 All  interfaces  added  to  batman  advanced are not relevant any
 111 longer because batman handles them for you. Basically, one "hands
 112 over" the data by using the batman interface and batman will make
 113 sure it reaches its destination.
 114
 115 The "bat0" interface can be used like any  other  regular  inter-
 116 face.  It needs an IP address which can be either statically con-
 117 figured or dynamically (by using DHCP or similar services):
 118
 119 # NodeA: ifconfig bat0 192.168.0.1
 120 # NodeB: ifconfig bat0 192.168.0.2
 121 # NodeB: ping 192.168.0.1
 122
 123 Note:  In  order to avoid problems remove all IP addresses previ-
 124 ously assigned to interfaces now used by batman advanced, e.g.
 125
 126 # ifconfig eth0 0.0.0.0
 127
 128
 129 VISUALIZATION
 130 -------------
 131
 132 If you want topology visualization, at least one mesh  node  must
 133 be configured as VIS-server:
 134
 135 # echo "server" > /sys/class/net/bat0/mesh/vis_mode
 136
 137 Each  node  is  either configured as "server" or as "client" (de-
 138 fault: "client").  Clients send their topology data to the server
 139 next to them, and server synchronize with other servers. If there
 140 is no server configured (default) within the  mesh,  no  topology
 141 information   will  be  transmitted.  With  these  "synchronizing
 142 servers", there can be 1 or more vis servers sharing the same (or
 143 at least very similar) data.
 144
 145 When  configured  as  server,  you can get a topology snapshot of
 146 your mesh:
 147
 148 # cat /sys/kernel/debug/batman_adv/bat0/vis_data
 149
 150 This raw output is intended to be easily parsable and convertable
 151 with  other tools. Have a look at the batctl README if you want a
 152 vis output in dot or json format for instance and how those  out-
 153 puts could then be visualised in an image.
 154
 155 The raw format consists of comma separated values per entry where
 156 each entry is giving information about a  certain  source  inter-
 157 face.  Each  entry can/has to have the following values:
 158 -> "mac" - mac address of an originator's source interface
 159            (each line begins with it)
 160 -> "TQ mac  value"  -  src mac's link quality towards mac address
 161                        of a neighbor originator's interface which
 162                        is being used for routing
 163 -> "HNA mac" - HNA announced by source mac
 164 -> "PRIMARY" - this  is a primary interface
 165 -> "SEC mac" - secondary mac address of source
 166                (requires preceding PRIMARY)
 167
 168 The TQ value has a range from 4 to 255 with 255 being  the  best.
 169 The HNA entries are showing which hosts are connected to the mesh
 170 via bat0 or being bridged into the mesh network.  The PRIMARY/SEC
 171 values are only applied on primary interfaces
 172
 173
 174 LOGGING/DEBUGGING
 175 -----------------
 176
 177 All error messages, warnings and information messages are sent to
 178 the kernel log. Depending on your operating  system  distribution
 179 this  can  be read in one of a number of ways. Try using the com-
 180 mands: dmesg, logread, or looking in the files  /var/log/kern.log
 181 or  /var/log/syslog.  All  batman-adv  messages are prefixed with
 182 "batman-adv:" So to see just these messages try
 183
 184 # dmesg | grep batman-adv
 185
 186 When investigating problems with your mesh network  it  is  some-
 187 times  necessary  to see more detail debug messages. This must be
 188 enabled when compiling the batman-adv module. When building  bat-
 189 man-adv  as  part of kernel, use "make menuconfig" and enable the
 190 option "B.A.T.M.A.N. debugging".
 191
 192 Those additional  debug messages can be accessed  using a special
 193 file in debugfs
 194
 195 # cat /sys/kernel/debug/batman_adv/bat0/log
 196
 197 The additional debug output is by default disabled. It can be en-
 198 abled  during run time. Following log_levels are defined:
 199
 200 0 - All  debug  output  disabled
 201 1 - Enable messages related to routing / flooding / broadcasting
 202 2 - Enable route or hna added / changed / deleted
 203 3 - Enable all messages
 204
 205 The debug output can be changed at runtime  using  the  file
 206 /sys/class/net/bat0/mesh/log_level. e.g.
 207
 208 # echo 2 > /sys/class/net/bat0/mesh/log_level
 209
 210 will enable debug messages for when routes or HNAs change.
 211
 212
 213 BATCTL
 214 ------
 215
 216 As batman advanced operates on layer 2 all hosts participating in
 217 the  virtual switch are completely transparent for all  protocols
 218 above layer 2. Therefore the common diagnosis tools do  not  work
 219 as  expected.  To  overcome these problems batctl was created. At
 220 the  moment the  batctl contains ping,  traceroute,  tcpdump  and
 221 interfaces to the kernel module settings.
 222
 223 For more information, please see the manpage (man batctl).
 224
 225 batctl is available on http://www.open-mesh.org/
 226
 227
 228 CONTACT
 229 -------
 230
 231 Please send us comments, experiences, questions, anything :)
 232
 233 IRC:            #batman   on   irc.freenode.org
 234 Mailing-list:   b.a.t.m.a.n@open-mesh.org (optional  subscription
 235           at 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>