[Olsr-dev] local broadcast/custom message types

[Lotte Steenbrink]

Am 21.02.2013 um 07:23 schrieb Henning Rogge:

> On 02/20/2013 10:12 PM, Lotte Steenbrink wrote:
>> Hi, I'm part of a small group of students that try to experiment with
>> different forwarding strategies on mobile ad hoc networks (between
>> several nexus 7) using olsrd. For this, we need the devices to be
>> able to send local broadcasts that will only reach their
>> 1-hop-neighbors and will not be forwarded. I guess we need to
>> implement a custom message type, but the documentation on how to do
>> this exactly is kind of... Sparse. We're rummaging through the code
>> right now but since this is a frustrating thing to do and our time is
>> limited, I wanted to ask if anybody on this list has any ideas, would
>> like to help us or point us towards HOWTOs we might not have found
>> yet?
> 
> Just to explain it a little bit more, you do not need OLSRd code support for sending messages of a service one-hop, you just need an UDP Socket that sends either broadcast or multicast messages.
> 

As far as I/we understood it, the TTL that olsr routers (so in our case the nexus 7s) will decrement is the one in the olsr-header. If they get a packet that does not have this header, they will forward it to whatever hop they consider appropriate, flooding the subnet that forms our MANET with these broadcasts (and only the gateway node would actually decrement the IP TTL). 
So based on this assumption we figured it would be a better idea to make use of the already implemented header creation rather than build these packets from scratch... Is this assumption correct?

Greetings,
Lotte

> If you use Multicast and IPv6, you should use a linklocal Multicast.
> 
> Henning Rogge
> 
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