[B.A.T.M.A.N.] TTL-Interface specific

[B.A.T.M.A.N.] TTL-Interface specific

[Freifunk Dresden]

Hello,

In the documentation was written that a specific TTL can be assigned  
to each interface. How can I do this from command line?
I have two interfaces eth1 (wlan) and bbs (a VPN tap tunnel used as backbone).

Those interfaces are not bridged and have different ip ranges
eth1: 10.12.x.x
bbs: 172.16.x.x

My aim is only to propagate the 10.12.x.x ip range and not the 172.16er.
The 172.16 of any foreign router should not be listed in any routing  
table of any other router. Only the local interface address of bbs  
should be seen in the routing table.
I have read that this can be solved by setting the TTL for bbs to a  
value of 1.
I need to know how I can do this.

Questions 2:
  batman on mipsel runs in three instances independed of number of  
interfaces listen. on i386 only one instance is running (three  
interfaces). How does this work?

ddmesh (dresden freifunk)

Re: [B.A.T.M.A.N.] TTL-Interface specific

[Axel Neumann]

Hello,

On Friday 20 July 2007 17:25, Freifunk Dresden wrote:
> Hello,
>
> In the documentation was written that a specific TTL can be assigned
> to each interface. How can I do this from command line?
> I have two interfaces eth1 (wlan) and bbs (a VPN tap tunnel used as
> backbone).
>
> Those interfaces are not bridged and have different ip ranges
> eth1: 10.12.x.x
> bbs: 172.16.x.x
>
> My aim is only to propagate the 10.12.x.x ip range and not the 172.16er.
> The 172.16 of any foreign router should not be listed in any routing
> table of any other router. Only the local interface address of bbs
> should be seen in the routing table.
> I have read that this can be solved by setting the TTL for bbs to a
> value of 1.
> I need to know how I can do this.

We removed this feature from the stable branch because many people were 
confused when using an interface with a small batman-ttl for outgoing 
traffic. In such case, the destination node of the traffic does not know 
where to reply.
In general, no problems occur if the (two-interface) node is not generating 
traffic itself

Currently a -t option is included in trunk/batman-experimental which allows to 
specify the ttl to be used for all interfaces. Applying different ttl-values 
for different interfaces conceptually works but setting these values with the 
command line is on the TODO list.

regards,
axel

Re: [B.A.T.M.A.N.] TTL-Interface specific

[Marek Lindner]

Hi,


> Questions 2:
>   batman on mipsel runs in three instances independed of number of
> interfaces listen. on i386 only one instance is running (three
> interfaces). How does this work?

the words "instances" means threads. I guess you found that word on the batman 
freifunk gui ?! It is a bit misleading.
Batman is a threaded application. Several tasks are done by different threads. 
OpenWRT (Whiterussian) has no good thread implementation - so called 
LinuxThreads. They emulate thread behaviour via processes. Thats why you see 
so many. 
However, this library is deprecated and a newer (NPTL) is in widely use today 
but requires Linux Kernel 2.6. This is a real thread implementation where you 
have only one process. I guess that you use this lib on your i386 ?!

Regards,
Marek