updated README

Hey,

Andrew pointed out that our README would need a little bit of love. I spent some time to get the text into a decent shape. I attached the full file for a review. Let me know if you find anything. :)

Cheers,
Marek

[state: 03-05-2010]

BATMAN-ADV
----------

Batman advanced is a new approach to wireless networking which does no longer operate on the IP basis. Unlike the batman daemon, which exchanges information using UDP packets and sets routing tables, batman-advanced operates on ISO/OSI Layer 2 only and uses and routes (or better: bridges) Ethernet Frames. It emulates a virtual network switch of all nodes participating. Therefore all nodes appear to be link local, thus all higher operating protocols won't be affected by any changes within the network. You can run almost any protocol above batman advanced, prominent examples are: IPv4, IPv6, DHCP, IPX.

Batman advanced was implemented as a Linux kernel driver to reduce the overhead to a minimum. It does not depend on any (other) network driver, and can be used on wifi as well as ethernet lan, vpn, etc ... (anything with ethernet-style layer 2). It compiles against and should work with Linux 2.6.20 - 2.6.33. Supporting older versions is not planned, but it's probably easy to backport it. If you work on a backport, feel free to contact us. :-)

COMPILE
-------
To compile against your currently installed kernel, just type:

# make

if you want to compile against some other kernel, use:

# make KERNELPATH=/path/to/kernel

CONFIGURATION
-------------

Load the batman-adv module into your kernel:

# insmod batman-adv.ko

The module is now waiting for activation. You must add some interfaces on which batman can operate. After loading the module batman advanced will scan your systems interfaces to search for compatible interfaces. Once found, it will create subfolders in the /sys directories of each supported interface, e.g.

# ls /sys/class/net/eth0/batman_adv/

If an interface does not have the "batman_adv" subfolder it probably is not supported. Not supported interfaces are: loopback, non-ethernet and batman's own interfaces.

Note: After the module was loaded it will continuously watch for new interfaces to verify the compatibility. There is no need to reload the module if you plug your USB wifi adapter into your machine after batman advanced was initially loaded.

To activate a given interface simply write "bat0" into its "mesh_iface" file inside the batman_adv subfolder:

# echo bat0 > /sys/class/net/eth0/batman_adv/mesh_iface

Repeat this step for all interfaces you wish to add. Now batman starts using/broadcasting on this/these interface(s).

By reading the "iface_status" file you can check its status:

# cat /sys/class/net/eth0/batman_adv/iface_status

To deactivate an interface you have to write "none" into its "mesh_iface" file:

# echo none > /sys/class/net/eth0/batman_adv/mesh_iface

All mesh wide settings can be found in batman's own interface folder:

# ls /sys/class/net/bat0/mesh/

Some of the files contain all sort of status information regarding the mesh network. For exmaple, you can view the table of originators (mesh participants) with:

# cat /sys/class/net/bat0/mesh/originators

Other files allow to change batman's behaviour to better fit your requirements. For instance, you can check the current originator interval (value in milliseconds which determines how often batman sends its broadcast packets):

# cat /sys/class/net/bat0/mesh/orig_interval

and also change its value:

# echo 3000 > /sys/class/net/bat0/mesh/orig_interval

In very mobile scenarios, you might want to adjust the originator interval to a lower value. This will make the mesh more responsive to topology changes, but will also increase the overhead.

USAGE
-----

To make use of your newly created mesh, batman advanced provides a new interface "bat0" which you should use from this point on. All interfaces added to batman advanced are not relevant any longer because batman handles them for you. Basically, one "hands over" the data by using the batman interface and batman will make sure it reaches its destination.

The "bat0" interface can be used like any other regular interface. It needs an IP address which can be either statically configured or dynamically (by using DHCP or similar services):

# NodeA: ifconfig bat0 192.168.0.1 up
# NodeB: ifconfig bat0 192.168.0.2 up
# NodeB: ping 192.168.0.1

Note: In order to avoid problems remove all IP addresses previously assigned to interfaces now used by batman advanced, e.g.

# ifconfig eth0 0.0.0.0

VISUALIZATION
-------------

If you want topology visualization, at least one mesh node must be configured as VIS-server:

# echo "server" > /sys/class/net/bat0/mesh/vis_mode

Each node is either configured as "server" or as "client" (default: "client"). Clients send their topology data to the server next to them, and server synchronize with other servers. If there is no server configured (default) within the mesh, no topology information will be transmitted. With these "synchronizing servers", there can be 1 or more vis servers sharing the same (or at least very similar) data.

When configured as server, you can get a topology snapshot of your mesh:

# cat /sys/class/net/bat0/mesh/vis_data

This raw output is intended to be easily parsable and convertable with other tools. Have a look at the batctl README if you want a vis output in dot or json format for instance and how those outputs could then be visualised in an image.

The raw format consists of comma seperated values per entry where each entry is giving information about a certain source interface. Each entry can/has to have the following values:
-> "mac" -> mac address of an originator's source interface
(each line begins with it)
-> "TQ mac value" -> src mac's link quality towards mac address of a neighbor
originator's interface which is being used for routing
-> "HNA mac" -> HNA announced by source mac
-> "PRIMARY" -> this is a primary interface
-> "SEC mac" -> secondary mac address of source (requires preceeding PRIMARY)

The TQ value has a range from 4 to 255 with 255 being the best. The HNA entries are showing which hosts are connected to the mesh via bat0 or being bridged into the mesh network.
The PRIMARY/SEC values are only applied on primary interfaces

LOGGING/DEBUGGING
-----------------

All error messages, warnings and information messages are sent to the kernel log. Depending on your operating system distribution this can be read in one of a number of ways. Try using the commands: dmesg, logread, or looking in the files /var/log/kern.log or /var/log/syslog. All batman-adv messages are prefixed with "batman-adv:" So to see just these messages try

# dmesg | grep batman-adv

When investigating problems with your mesh network it is sometimes necessary to see more detail debug messages. This must be enabled when compiling the batman-adv module. When building batman-adv as part of kernel, use "make menuconfig" and enable the option "B.A.T.M.A.N. debugging". When compiling outside of the kernel tree it is necessary to edit the file Makefile.kbuild and uncomment the line

#EXTRA_CFLAGS += -DCONFIG_BATMAN_ADV_DEBUG

The additional debug output is by default disabled. It can be enabled either at kernel modules load time or during run time. To enable debug output at module load time, add the module parameter debug=<value>.
<value> can take one of four values.

0 - All debug output disabled
1 - Enable messages related to routing / flooding / broadcasting 2 - Enable route or hna added / changed / deleted
3 - Enable all messages

e.g.

# modprobe batman-adv debug=2

will load the module and enable debug messages for when routes or HNAs change.

The debug output can also be changed at runtime using the file /sys/module/batman-adv/parameters/debug. e.g.

# echo 2 > /sys/module/batman-adv/parameters/debug

enables debug messages for when routes or HNAs

The debug output is sent to the kernel logs. So try dmesg, logread, etc to see the debug messages.

BATCTL
------

As batman advanced operates on layer 2 all hosts participating in the virtual switch are completely transparent for all protocols above layer 2. Therefore the common diagnosis tools do not work as expected. To overcome these problems batctl was created. At the moment the batctl contains ping, traceroute, tcpdump and interfaces to the kernel module settings.

For more information, please see the manpage (man batctl).

batctl is available on http://www.open-mesh.org/

CONTACT
-------

Please send us comments, experiences, questions, anything :)

IRC:             #batman on irc.freenode.org
Mailing-list:    [email protected]

(optional subscription at https://lists.open-mesh.org/mm/listinfo/b.a.t.m.a.n)

You can also contact the Authors:

Marek Lindner <[email protected]>
Simon Wunderlich <[email protected]>

Sounds good, but noticed some small typos:

* exmaple -> example
* seperated -> separated
* preceeding -> preceding

And maybe you should increase "Linux 2.6.20" to "Linux 2.6.21" with your newest backporting efforts.

Best regards,
Sven

Hi,

thanks! I corrected them on my end.
Can any native English speaker check the text and give us her/his blessing ?

I kept the "Linux 2.6.20" in the hope that the recent patches would also make our code work on this old release. I just did not test it. Do we have reason to believe that it won't work ?

Regards,
Marek

Yes, I tested it some days ago and some structs changed in a way we would have problems to support them. Unless you have reasons that we need to support them I would keep that as exercise for the interested reader.

Best regards,
Sven

Hi All,

I wonder if a brief explanation of how TQ is determined belongs here
too?

warm regards,
Wiz

Hi,

I find it quite hard write a short paragraph about the TQ stuff, since I either end up simplifying the whole matter or writing too much text. On top of that, I'm not so sure what the casual reader would expect to find in the README regarding the routing algo. Maybe you could draft something and we go from there ?

Cheers,
Marek

Hi Marek,

Alas, I don't know enough about how it works to be of much help.

I *DO* have it running on a pair of Meraki minis with villagetelco
software. Seems to work *VERY* well.

I always seem to be looking for a real-time quality monitor so I can
adjust antennas, check range, watch radios change by themselves, etc. i.e.- A real-time chart recorder widget. Thus my suggestion.

Congratulations to all :).

warm regards,
Wiz

Hi,

glad to hear that !

You are not the first one with such a feature request but let me point out that batman is not the right tool for the job. If you want to finetune antennas batman is way too slow and imprecise, since all it does is measuring packet loss within a certain time frame. Deriving antenna directions from that is more magic than real sience.

I'd rather suggest a tool like "horst" (Highly Optimized Radio Scanning Tool -
http://br1.einfach.org/tech/horst/) which hooks into your wifi driver to retrieve real-time data about the link quality to your neighbors. Of course, such a tool is highly dependend on the wifi driver and probably does not support all the drivers in the world but I'm sure it can be extended.

Regards,
Marek

Hi, thank you very much for your suggestion!
It is very usefull here! :)

Hi Marek

I reviewed it and made some changes. There are also some suggestion inside [ ] marks.

Andrew

[state: 03-05-2010]

BATMAN-ADV
----------

Batman advanced is a new approach to wireless networking which no longer operate on the IP level. Unlike the batman daemon, which exchanges information using UDP packets and sets entries in routing tables, batman-advanced operates on ISO/OSI Layer 2. It uses and routes (or better: bridges) Ethernet Frames. It emulates a virtual network switch containing all of the participating nodes. Therefore all nodes appear to be link local to each other. All protocols operating at higher won't be affected by any changes within the mesh network. You can run almost any protocol above batman advanced, prominent examples are: IPv4, IPv6, DHCP and IPX.

Batman advanced is implemented as a Linux kernel driver, so reducing the overheads to a minimum. It does not depend on any (other) network driver, and can be used on wifi as well as ethernet lan, vpn, etc ... (anything with ethernet-style layer 2). It compiles against and should work with Linux 2.6.20 - 2.6.33. Supporting older versions is not planned, but it's probably easy to backport it. If you work on a backport, feel free to contact us. :-)

COMPILE
-------
To compile against your currently installed kernel, just type:

# make

if you want to compile against some other kernel, use:

# make KERNELPATH=/path/to/kernel

CONFIGURATION
-------------

Load the batman-adv module into your kernel:

# insmod batman-adv.ko

The module is now waiting for activation. You must add some interfaces on which batman can operate. After loading the module batman advanced will scan your systems interfaces to search for compatible interfaces. Once found, it will create subfolders in the /sys directories for each supported interface, e.g.

# ls /sys/class/net/eth0/batman_adv/

[Might be nice to show the output here]

If an interface does not have the "batman_adv" subfolder it probably is not supported. Not supported interfaces are: loopback, non-ethernet and batman's own interfaces.

Note: After the module is loaded it will continuously watch for new interfaces to verify the compatibility. There is no need to reload the module if you plug your USB wifi adapter into your machine after batman advanced was initially loaded.

To activate a given interface simply write "bat0" into its "mesh_iface" file inside the batman_adv subfolder:

# echo bat0 > /sys/class/net/eth0/batman_adv/mesh_iface

Repeat this step for all interfaces you wish to add. Now batman starts using/broadcasting on this/these interface(s).

By reading the "iface_status" file you can check its status:

# cat /sys/class/net/eth0/batman_adv/iface_status

[Might be nice to show the contents of the file]

To deactivate an interface you have to write "none" into its "mesh_iface" file:

# echo none > /sys/class/net/eth0/batman_adv/mesh_iface

All mesh wide settings can be found in batman's own interface folder:

# ls /sys/class/net/bat0/mesh/

[Might be nice to list the files]

Some of the files contain all sort of status information regarding the mesh network. For example, you can view the table of originators (mesh participants) with:

# cat /sys/class/net/bat0/mesh/originators

Other files allow to change batman's behaviour to better fit your requirements. For instance, you can check the current originator interval (value in milliseconds which determines how often batman sends its broadcast packets):

# cat /sys/class/net/bat0/mesh/orig_interval

[Might be nice to show the contents of the file]

and also change its value:

# echo 3000 > /sys/class/net/bat0/mesh/orig_interval

In very mobile scenarios, you might want to adjust the originator interval to a lower value. This will make the mesh more responsive to topology changes, but will also increase the overhead.

USAGE
-----

To make use of your newly created mesh, batman advanced provides a new interface "bat0" which you should use from this point on. All interfaces added to batman advanced are not relevant any longer because batman handles them for you. Basically, one "hands over" the data by using the batman interface and batman will make sure it reaches its destination.

The "bat0" interface can be used like any other regular interface. It needs an IP address which can be either statically configured or dynamically (by using DHCP or similar services):

# NodeA: ifconfig bat0 192.168.0.1 up
# NodeB: ifconfig bat0 192.168.0.2 up
# NodeB: ping 192.168.0.1

Note: In order to avoid problems remove all IP addresses previously assigned to interfaces now used by batman advanced, e.g.

# ifconfig eth0 0.0.0.0

VISUALIZATION
-------------

If you want topology visualization, at least one mesh node must be configured as VIS-server:

# echo "server" > /sys/class/net/bat0/mesh/vis_mode

Each node is either configured as "server" or as "client" (default:
"client"). Clients send their topology data to the server next to them, and servers synchronize with other servers. If there is no server configured (default) within the mesh, no topology information will be transmitted. With these "synchronizing servers", there can be 1 or more vis servers sharing the same (or at least very similar) data.

When configured as server, you can get a topology snapshot of your mesh:

# cat /sys/class/net/bat0/mesh/vis_data

This raw output is intended to be easily parsable and convertible with other tools. Have a look at the batctl README if you want a vis output in dot or json format for instance and how those outputs could then be visualised in an image.

The raw format consists of comma separated values per entry where each entry is giving information about a certain source interface. Each entry can/has to have the following values:
-> "mac" -> mac address of an originator's source interface
(each line begins with it)
-> "TQ mac value" -> src mac's link quality towards mac address of a
neighbor originator's interface which is being used for routing
-> "HNA mac" -> HNA announced by source mac
-> "PRIMARY" -> this is a primary interface
-> "SEC mac" -> secondary mac address of source (requires preceding
PRIMARY)

The TQ value has a range from 4 to 255 with 255 being the best. The HNA entries are showing which hosts are connected to the mesh via bat0 or being bridged into the mesh network.
The PRIMARY/SEC values are only applied on primary interfaces

LOGGING/DEBUGGING
-----------------

All error messages, warnings and information messages are sent to the kernel log. Depending on your operating system distribution this can be read in one of a number of ways. Try using the commands: dmesg, logread, or looking in the files /var/log/kern.log or /var/log/syslog. All batman-adv messages are prefixed with "batman-adv:" So to see just these messages try

# dmesg | grep batman-adv

When investigating problems with your mesh network it is sometimes necessary to see more detail debug messages. This must be enabled when compiling the batman-adv module. When building batman-adv as part of kernel, use "make menuconfig" and enable the option "B.A.T.M.A.N. debugging". When compiling outside of the kernel tree it is necessary to edit the file Makefile.kbuild and uncomment the line

#EXTRA_CFLAGS += -DCONFIG_BATMAN_ADV_DEBUG

The additional debug output is by default disabled. It can be enabled either at kernel modules load time or during run time. To enable debug output at module load time, add the module parameter debug=<value>. <value> can take one of four values.

0 - All debug output disabled
1 - Enable messages related to routing / flooding / broadcasting 2 - Enable route or hna added / changed / deleted
3 - Enable all messages

e.g.

# modprobe batman-adv debug=2

will load the module and enable debug messages for when routes or HNAs change.

The debug output can also be changed at run time using the file /sys/module/batman-adv/parameters/debug. e.g.

# echo 2 > /sys/module/batman-adv/parameters/debug

enables debug messages for when routes or HNAs

The debug output is sent to the kernel logs. So try dmesg, logread, etc to see the debug messages.

BATCTL
------

As batman advanced operates on layer 2 all hosts participating in the virtual switch are completely transparent for all protocols above layer 2. Therefore the common diagnosis tools do not work as expected. To overcome these problems batctl was created. At the moment the batctl contains ping, traceroute, tcpdump and interfaces to the kernel module settings.

For more information, please see the manpage (man batctl).

batctl is available on http://www.open-mesh.org/

CONTACT
-------

Please send us comments, experiences, questions, anything :)

IRC:             #batman on irc.freenode.org
Mailing-list:    [email protected]

(optional subscription at https://lists.open-mesh.org/mm/listinfo/b.a.t.m.a.n)

You can also contact the Authors:

Marek Lindner <[email protected]>
Simon Wunderlich <[email protected]>

Hi,

thanks for all the input so far.

Changelog:
* typos found by Sven and Andrew corrected
* some output added as suggested by Andrew
* increased "Linux 2.6.20" to "Linux 2.6.21" since we don't support 2.6.20 at this moment
* piped the README through nroff to get a consistent look & feel

The file is in the repos now.

Cheers,
Marek

Hi Marek

It looks like this stage made use of UTF-8, or some sort of extended character set:

vpn, etc ... (anything with ethernet<E2><80><90>style layer 2). It compiles
against and should work with Linux 2.6.21 <E2><80><90> 2.6.33. Supporting
older versions is not planned, but it<E2><80><99>s probably easy to backport

I don't have a locale set, being an English speaker and not needing umlauts, accents, etc. I guess most embedded systems also don't have locale support.

Could we have a 7-bit clean README?

Thanks
Andrew

Ok, just committed a utf8 stripped version. You are probably right: nroff added them.

Well, I don't think people would go through the hassle of copying the README onto a router to read it over the serial console. ;-)

Cheers,
Marek